■jr. :nc AEROGRAPHER'S MATE 3 & of ry NAVAL EDUCATION AND TRAINING COMMAND RATE TRAINING MANUAL AND NONRESIDENT CAREER COURSE NAVEDTRA 10363 E FEB '0? Zt^::Z h / PW ' Wri — <»e date below 78733 L162 Ae.S PREFACE The ultimate purpose of training Naval personnel is to produce a combatant Navy which can ensure victory at sea. A consequence of the quality of training given them is their superior state of readi- ness. Its result is a victorious Navy. This Rate Training Manual and Nonresident Career Course (RTM/ NRCC) form a self-study package that will enable ambitious Aerog- rapher's Mates to help themselves fulfill the requirements of their rating. Designed for individual study and not formal classroom instruc- tion, the RTM provides subject matter that relates directly to the occupational qualifications of the Aerographer's Mate rating. The NRCC provides the usual way of satisfying the requirements for completing the RTM. The set of assignments in the NRCC includes learning objectives and supporting items designed to lead students through the RTM. The Rate Training Manual and Nonresident Career Course were prepared by the Naval Education and Training Program Development Center, Pensacola, Florida, for the Chief of Naval Education and Training. Technical assistance was provided by the Aerographer's Mate School, Lakehurst, New Jersey and Naval Weather Service Facility, Pensacola, Florida. Stock Ordering No. 0502-LP-051-8160 1976 Edition WITHDRAWN University of Illinois Library Published by NAVAL EDUCATION AND TRAINING SUPPORT COMMAND UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON, D.C. 1976 i THE UNITED STATES NAVY GUARDIAN OF OUR COUNTRY The United States Navy is responsible for maintaining control of the sea and is a ready force on watch at home and overseas, capable of strong action to preserve the peace or of instant offensive action to win in war. It is upon the maintenance of this control that our country's glorious future depends; the United States Navy exists to make it so. WE SERVE WITH HONOR Tradition, valor, and victory are the Navy's heritage from the past. To these may be added dedication, discipline, and vigilance as the watchwords of the present and the future. At home or on distant stations we serve with pride, confident in the respect of our country, our shipmates, and our families. Our responsibilities sober us; our adversities strengthen us. Service to God and Country is our special privilege. We serve with honor. THE FUTURE OF THE NAVY The Navy will always employ new weapons, new techniques, and greater power to protect and defend the United States on the sea, under the sea, and in the air. Now and in the future, control of the sea gives the United States her greatest advantage for the maintenance of peace and for victory in war. Mobility, surprise, dispersal, and offensive power are the keynotes of the new Navy. The roots of the Navy lie in a strong belief in the future, in continued dedication to our tasks, and in reflection on our heritage from the past. Never have our opportunities and our responsibilities been greater. ii CONTENTS CHAPTER Page 1. Aerographer's Mate Rating 1 2. Pressure 16 3. Wind equipment 33 4. Temperature, humidity, and precipitation 50 5. Clouds and visibility 70 6. Radar and satellite equipment 102 7. Communications equipment and operational procedures 123 8. Office equipment 148 9. Specialized meteorological equipment and their uses 155 10. Watch routines 164 11. Watch routines (continued) 193 12. The governing fundamentals of meteorology 249 13. Circulation of the atmosphere 289 14. Air masses and fronts 312 15. Meteorological elements 346 16. Fundamentals of oceanography 371 17. Administration, publications, and supply 397 APPENDIX I. The Metric System 422 II. Glossary 424 iii CHAPTER Page III. Explanation of weather code figures and symbols 428 IV. Federal Meteorological Form 1-10 Surface Weather Observations (NWSC 3140/7) 429 V. Surface Weather Observations (Ship) Form (NWSC 3140/8) 431 VI. Wind wave/wind speed table 433 VII. Aerial Meteorological Reconnaissance Reporting Code (RECCO CODE OPNAV 3140-2) 434 VIII. Bathythermograph Log (OCEANAV 3167/1) 435 IX. Weather data designators 437 X. AN nomenclature system 438 XI. Electrical and electronic terms 442 XII. Map projections 445 XIII. Flight Forecast Folder (OPNAV Form 3140/25) 446 XIV. Naval Weather Service Command Meteorological Records Transmittal Form (NWSC Form 3140/6) .... 448 XV. Meteorological Station Description and Instrumentation Report (NWSC Form 3140/5) 449 INDEX 450 Nonresident Career Course follows Index iv CHAPTER 1 AEROGRAPHER'S MATE RATING This Rate Training Manual is designed as a self-study text for use by those personnel of the Navy and Naval Reserve who are pre- paring to meet the professional (technical) qual- ifications for advancement to Petty Officer Third Class and Petty Officer Second Class in the Aerographer's Mate (AG) rating. A second pur- pose of this manual is the improvement of job skills. This purpose is achieved through use of the manual as a study aid in conjunction with on-the-job training. Minimum professional qualifications for ad- vancement in all ratings are listed in the Manual of Navy Enlisted Manpower and Personnel Classifications and Occupational Standards, NAVPERS 18068 (Series). Formerly designated as the Manual of Qualifications for Advancement, NAVPERS 18068 is often referred to as the "Quals" Manual. The occupational standards upon which this Rate Training Manual is based are those appear- ing in Change C of NAVPERS 18068. It should be kept in mind that any changes in the quali- fications occurring after the (C) revision of the "Quals" Manual may not be reflected in the information presented in this training man- ual. This chapter provides information on the enlisted rating structure, the AG rating, re- quirements and procedures for advancement, and references that will help you in working for advancement and in performing your duties as an AG. Also included is information on how to make the best use of Rate Training Manuals. It is therefore strongly recommended that you study this chapter carefully before beginning intensive study of the remainder of the manual. ENLISTED RATING STRUCTURE The present enlisted rating structure con- sists of general ratings and service ratings. General ratings identify broad occupational fields of related duties and functions. Some general ratings include service ratings; others do not. Both Regular Navy and Naval Reserve personnel may hold general ratings. The general rating provides the primary means of identifying billet requirements and personnel qualifications; it is established or disestablished by the Secretary of the Navy; and it is provided a distinctive rating badge. The general rate is the pay grade level within the general rating. Service ratings identify subdivisions or specialities within a general rating which re- quire related patterns of aptitudes and qualifi- cations, and which provide paths of advancement for career development. Although service ratings can exist at any petty officer level, they are most common at the P03 and P02 levels. Both Regular Navy and Naval Reserve personnel may hold service ratings. The Navy Enlisted Classification Coding System (NEC) has been set up to help the Navy match the right person with the right job. By identifying billets that require special skills, and by identifying people who have or can develop these special skills, the NEC sys- tem provides the Navy with a means of getting maximum usefulness from its manpower. Any person who gains the qualifications associated with one of the special skills is given a code number called his NEC. AEROGRAPHER'S MATE RATING Due to the demands of World War I, the United States Navy in 1917 designated some men as aerological personnel for the first time. The first group consisted of two hundred men of various ratings who received special train- ing in meteorology. AEROGRAPHER'S MATE 3 & 2 The first aerological personnel held the rat- ing of Quartermaster with meteorological duties (QMA). This was changed in 1923 to Aerog- rapher (Aerog). With the establishment of the warrant rank in 1942, the rating became Aerog- rapher's Mate (AerM). In 1948 the rating be- came Aerographer's Mate (AG), which is one of the Group IX or aviation ratings. There is no service rating provided for Aerographer's Mates. Figure 1-1 illustrates all paths of advance- ment for an Airman Recruit to Master Chief Aerographer's Mate (AGCM). Notice that each enlisted pay grade has a name; for example, E-l, recruit. An E-4 is called Aerographer's Mate 3rd class; an E-9 is called Master Chief Aerographer's Mate. Figure 1-2(A) illustrates the active duty advancement requirements from E-l through E-9. Figure 1-2(B) illustrates the inactive duty advancement requirements. It is difficult to differentiate the type of work performed at various rate levels of the Aerog- rapher's Mate rating. The work largely de- pends upon the mission of the weather unit and the personnel available to accomplish the mis- sion. However, an attempt will be made to generalize the basic duties of the two lower rates. As an Aerographer's Mate 3, you must be able to operate weather facsimile and teletype equipment; Automatic Picture Transmission (APT) Satellite receiving equipment; perform routine checks and operator's preventive main- tenance of meteorological and oceanographic equipment; make, record, and prepare for transmission surface and upper wind observa- tions; decode weather codes and plot data on surface and upper air charts; decode and plot oceanographic data; decode and plot a radio- logical fallout message; and typewrite for 5 minutes at 20 words per minute. As an Aerographer's Mate 3, you must know the application of basic laws of motion, gases, heat, and energy to meteorology; general char- acteristics of air masses and basic frontal sys- tems; structure and composition of the atmosphere; precautionary measures to be ob- served in the care and handling of meteorologi- cal, oceanographic, and Naval Environmental AG2 E-3 A63 E-4 —J— AIRMAN E-3 AIRMAN APPRENTICE E-2 1 AIRMAN RECRUIT E-l Figure 1-1. — Path of 209.1 advancement. Data Network (NEDN) tie-line equipment; oper- ating principles and functions of standard non- electronic meteorological and oceanographic instruments; meteorological and oceanographic terminology; legends used on analyzed charts; common symbols and codes used in surface, upper air, airways, and oceanographic obser- vations; and principles and procedures of visual upper wind observations (PIBAL), of meteoro- logical satellite observations, and of sea condi- tion observations. As an Aerographer's Mate 2, you must be able to sketch synoptic meteorological surface Chapter 1 — AEROGRAPHER'S MATE RATING REQUIREMENTS* SERVICE SCHOOL PERFORMANCE TEST El to E2 4 mos. servlce- or comple- tion of Recruit Training. Recruit Training. (C.O. may ad- vance up to 10% of gradu- ating class.} E2 to E2 8 mos. as E-2, # E3 to E4 » E4 to E5 6 mos. as E-3. 2 years time in service. Class A for PR3, DT3, PT3, AME 3, HM3, PN3, FTB 3, MT3, 12 mos. as E-4. 3 years time in service. E5 to E6 24 mos. as E-5. 6 years time in service. fE6 to E7 36 mos. as E-6. 9 years time in service. Navy School for AGC, MUC, MNC.tt Specified ratings must complete applicable performance tests be- fore taking examinations. |E7 to E8 36 mos. as E-7. 8 of 12 years time in service must be enlisted. T • t T 1 1 II I 1 fE8 to E9 36 mos. as E-8. 10 of 15 years time in service must be enlisted. '•■•• ENLISTED PERFORMANCE EVALUATION As used by CO when approving advancement. Counts toward performance factor credit in ad- vancement multiple. EXAMINATIONS** Locally prepared tests. See below. Navy wide examinations required for all PO advancements. Navywide selection board. RATE TRAINING MANUAL (INCLUD- ING MILITARY REQUIREMENTS) Required for E-3 and all PO advancements unless waived because of school comple- tion, but need not be repeated if identical course has already been completed. See NAVEDTRA 10052 (current edition). Nonresident career courses and recommended reading. See NAVEDTRA 10052 (current edition). AUTHORIZATION Commanding Officer NAVEDTRA PRODEVCEN * All advancements require commanding officer's recommendation. I 3 years obligated service required for E-7, E-8, and E-9. # Military leadership exam required for E-4 and E-5. ** For E-2 to E-3, NAVEDTRA PRODEVCEN exams or locally prepared testa may be used, tt Waived for qualified EOD personnel. Figure 1- 2(A). — Active duty advancement requirements. 3 AEROGRAPHER'S MATE 3 & 2 REQUIREMENTS * El to E2 E2 to E3 E3 to E4 E4 to E5 E5 to E6 E6 to E7 E8 E9 TOTAL TIME IN GRADE 4 mos. 6 mos. 6 mos. 12 mos. 24 mos. 36 mos. 36 mos. 24 mos. TOTAL TRAINING DUTY IN GRADE t 14 days 14 days 14 days 14 days 28 days 42 days 42 days 28 days PERFORMANCE TESTS Specified ratings must complete applicable performance tests before taking examination. DRILL PARTICIPATION Satisfactory participation as a member of a drill unit in accordance with BUPERSINST 5400.42 series. RATE TRAINING MANUAL (INCLUDING MILITARY REQUIRE- MENTS) Completion of applicable course or courses must be entered in service record. EXAMINATION Standard Exam Standard Exam required for all PO Advancements. Also pass Military Leadership Exam for E-4 and E-5. Standard Exam, Selection Board. AUTHORIZATION Commanding Officer Naval Examining Center Figure 1-2(B). — Inactive duty advancement requirements. 4 Chapter 1 — AEROGRAPHER'S MATE RATING and upper aircharts; decode and plot APT pre- dict messages and extract tracking data; demon- strate APT satellite gridding procedures and techniques; and construct and prepare for trans- mission a radiological fallout plot. The AG2 must also be capable of analyzing bathythermo- graph data for mixed or sonic layer depths and for thermal gradients and sound channels and of analyzing sea condition charts. He must also interpret oceanographic analyses and forecasts for operational use, and maintain weather office files of applicable notices, instructions, and manuals. It might be profitable to explore a few billets by tracing the possible career of one Aerog- rapher's Mate for his first 4-year enlistment. Assume that the man was assigned to a fleet weather central in the United States upon grad- uating from Aerographer's Mate School, Class A, and was classified as an AGAN. The man was given the job of taking surface weather ob- servations and entering synoptic reports on a weather chart. At first this work was done under close supervision. At times he assisted in tak- ing pibals or rawins and radiosonde observa- tions. As an AG2, if you are to perform the tasks referred to in the preceding paragraphs, you must know the primary, secondary, and tertiary circulations of the earth's atmosphere; types of weather associated with fronts, air masses, and cyclonic and anticyclonic systems; basic functions and general operating principles of standard electronic meteorological and oceano- graphic instruments; and the physical proper- ties of sea water and major current systems and water masses of the oceans. You must also know the principles and procedures of radiosonde and rawinsonde observations, the principles of radar observations, and the pro- cedures for requisitioning meteorological sup- plies, equipments, and publications. From the above general description of the professional requirements of Aerographer's Mates 3 and 2, you can readily see that only the highest caliber of personnel are desired for training as Aerographer's Mates. As Aerographer's Mates, you are aware that there are many types of billets to which men of your rating may be assigned. A person con- templating a 20-year naval career could not, if serving normal duty tours, serve in each type billet to which Aerographer's Mates are as- signed. A few types of duty assignments are Fleet Weather Centrals, instructor duty, polar expeditions, naval air stations, and shipboard duty on various types of ships. As for the future, it is impossible to antici- pate the billets that will be established and the ones that will be abolished. Technical develop- ments; changes in policy, organization, and op- erational requirements; and modification of meteorological concepts will all play a part in the determination of the billets of the future. After a 6-month period, assume that he completed the prescribed practical factors and successfully passed the rating examination and was advanced to Aerographer's Mate, Third Class. He continued to do the same type of work, but with less supervision. He also began learning to analyze weather charts and to make short-range forecasts. One year after being advanced to AG3 and upon the successful com- pletion of the advancement requirements and passing the rating examination, he was advanced to Aerographer's Mate, Second Class. After his normal tour of shore duty expired, he was transferred to an aircraft carrier. Aboard ship he took surface and upper air observations and supervised lower rated personnel. At times he ordered supplies and made out monthly and quarterly reports. Occasionally he analyzed weather charts and made short-range forecasts. During his tour of duty aboard the aircraft car- rier his enlistment expired. During this 4-year period he has been a part of the Navy. He has learned what it is to be a part of an organization. During the latter por- tion of his enlistment, he must give this one question some very serious thought: Shall I make the Navy my career? By this time he has been told of the many benefits the Navy affords, such as pay, travel, fringe, and retirement. With this knowledge of the security and mone- tary gains the Navy gives him, he also has the feeling of pride that being a part of the Navy team gives him. He knows that he is playing an important role in the defense of our demo- cratic way of life, and to preserve this way of life, he will want to keep on being a member of this Navy team. After carefully studying the situation, he will realize that by making the Navy his career, he will be doing his country, his family, and himself a great service. AEROGRAPHER'S MATE 3 & 2 Since you have been in pay grade E-3 or E-4 for some time, you realize that more leadership is required of the higher rates. Not only are you required to have superior knowledge, but you are also required to have the ability to handle personnel. This ability increases in importance as you advance through the various rates as a petty officer. In General Order No. 21, the Secretary of the Navy outlined some of the most important aspects of naval leadership. By naval leadership is meant the art of accomplishing the Navy's mission through people. It is the sum of those qualities of intellect, of human understanding, and of moral character that enables a person to inspire and to manage a group of people successfully. Effective leadership, therefore, is based on personal example, good management practices, and moral responsibility. The term leadership includes all three of these elements. The current Navy Leadership Program is designed to keep the spirit of General Order No. 21 ever before you. If the threefold ob- jective is carried out effectively in every com- mand, the program will make you a better leader of men in your present billet and in your future assignments. As you advance up the ladder of leadership, your worth to the Navy will be judged increasingly on the basis of the amount of efficient work you obtain from your subordinates rather than how much of the actual work you do yourself. For information on the practical application of leadership and supervision, study Military Requirements for Petty Officer 3 & 2, NAVEDTRA 10056 (Series). ADVANCEMENT Both you and the Navy benefit from your advancement. You get more pay, and your as- signments are more interesting and challenging. You can enjoy getting ahead in the Navy on your own efforts. Highly trained personnel are essential to the functioning of the Navy. By advancement, you increase your value to the Navy in two ways: First, you become more valuable as a technical specialist in your own rating; and second, you become more valuable as a person who can train others, and thus make far-reaching contributions to the entire Navy. The advancement system includes those re- quirements that must be met before you may be considered for advancement and those factors that actually determine whether or not you will be advanced. In this part of this chapter in- formation is presented to help you prepare and become qualified for advancement and to inform you of the method used for selecting those who will be advanced. BUPERS Notice 1418 will give you informa- tion on advancement examinations. Have your Educational Services Officer or your Training Petty Officer explain parts of these notices you do not understand. PREPARING FOR ADVANCEMENT What must you do to prepare for advancement? You must study the qualifications for advance- ment, complete the Personnel Advancement Re- quirements, study the required Rate Training Manuals and other material that is required. You will need to be familiar with the following: 1. Manual of Navy Enlisted Manpower and Personnel Classifications and Occupational Standards, NAVPERS 18068 (Series). 2. Personnel Advancement Requirements, NAVPERS 1414/4. 3. Bibliography for Advancement Study, NAVEDTRA 10052 (Series). 4. Applicable Rate Training Manuals and their companion Nonresident Career Courses. 5. Examination for advancement procedures. Collectively, these documents make up an integrated training package tied together by the occupational standards. The following paragraphs describe these materials and gives some infor- mation on how each one is related to the others. "Quals" Manual The Manual of Navy Enlisted Manpower and Personnel Classifications and Occupational Standards, NAVPERS 18068 (Series), gives the minimum requirements for advancement. This manual is usually called the "Quals" Manual, and the qualifications themselves are called occupational standards. The "Quals" Manual can be found in your Educational Services Office or may be obtained from your Training Petty Officer. 6 Chapter 1 — AEROGRAPHER'S MATE RATING Occupational standards are expressed as task statements only, unlike the advancement quali- fications which contain practical factors and knowledge factors. The approved concept for occupational standards is that they define what enlisted personnel must do in their rate or rating and that the knowledges required to per- form a task are inherent to the proper per- formance of the task. The practical and knowledge factors presently in the "Quals" Manual will be replaced with occupational standards. Occupational standards are identified by a five-digit number of which the first two digits identify the standard topic title and the remain- ing three digits identify the specific task state- ment. NOTE: As stated previously, the occupational standards upon which this Rate Training Manual is based are those appearing in NAVPERS 18068-C, which is titled Manual of Qualifications for Advancement. Therefore, the material is based on practical and knowledge factors which are identified by alphanumeric codes. For ex- ample, B1.01, "Operate facsimile and teletype equipment," is a knowledge factor under this system. In the new NAVPERS 18068 (Series), Manual of Navy Enlisted Manpower and Person- nel Classifications and Occupational Standards, the above occupational standard will probably appear as 86272, "Operate radio receivers, facsimile and teletype equipment." Any refer- ence to qualifications or occupational standards in this manual pertains to the old system. The standards are of two general types: military requirements and professional (or tech- nical) requirements. Military requirements apply to all ratings rather than to any one particular rating. Mili- tary requirements for advancement to third class and second class petty officer rates deal with military conduct, naval organization, military justice, security, watch standing, and other sub- jects which are required of petty officers in all other ratings. Professional requirements are technical or professional in nature and are directly related to the work of each rating. Both the military requirements and the professional requirements are divided into subject matter groups; then within each subject matter group, they are divided into specific task statements. The occupational standards for AG are listed in this manual following the index. Study these standards and the military requirements care- fully. The majority of the questions on your advancement examination will try to determine your understanding of the requirements reflected in the occupational standards. If you are work- ing for advancement to second class, remember that you may be examined on third class occu- pational standards as well as on second class occupational standards. It is essential that the occupational standards reflect current requirements of fleet and shore operations, and that new fleetwide technical, operational, and procedural developments be included. For these reasons, the occupational standards are continually under evaluation. Al- though there is an established schedule for revisions to the occupational standards for each rating, urgent changes to the occupational stand- ards may be made at any time. These revisions are issued in the form of changes to the "Quals" Manual. Therefore, never trust any set of occupational standards until you have checked the change number against an up-to-date copy of the "Quals" Manual. Be sure you have the latest revision. PERSONNEL ADVANCEMENT REQUIREMENT (PAR) PROGRAM NAVPERS 1414/4 The Personnel Advancement Requirement (PAR) Program is a new program initiated to replace the Record of Practical Factors (NAVEDTRA 1414/1). The former "quals" were stated in terms of practical factors and knowledge factors. The new occupational standards are presented only as task statements. This new format of the occupational standards does not lend itself to the practical factor checkoff list concept of the Record of Practical Factors. As a result, a new form and new concept of determining eligi- • bility for advancement has been developed. The Personnel Advancement Requirement (PAR) (NAVPERS 1414/4) will replace the Record of Practical Factors. This new system allows a command to evaluate the overall abilities of an individual in a day-to-day work situation, and eliminates the need to complete a mandatory, lengthy, and detailed checkoff list. The E-8 and E-9 are exempt from the program as there are other means of selection for ad- vancement to these paygrades. The E-3 AEROGRAPHER'S MATE 3 & 2 apprenticeships are so broad as to make the development of a single PAR impractical. Each rating PAR lists the requirements for advancement to paygrades E-4 through E-7 in one pamphlet. It contains descriptive information, instructions for administration, special rating requirements, and advancement requirements in the following sections: Section I — Administration Requirements Section II— Formal School and Training Re- quirements Section III — Occupational and Military Ability Requirements Section I contains the individuals' length of service, time in rate, and a checkoff for the individual having passed the E-4/E-5 Military Leadership Examination. Section II contains a checkoff entry for the individual having completed the Military Re- quirements Navy Training Course and the ap- plicable Navy Training Course for the rating. Section ni is a checkoff list of task state- ments. Items in this section are to be interpreted broadly and do not demand actual demonstra- tion of the item, or completion of alternate local examination, although demonstration is a com- mand prerogative. Individuals are evaluated on their ability to perform the task. Evaluation may be by observation of ability in related areas, training received, or by demonstration. There is currently a pilot program which includes the PQS watch station qualifications and preventive maintenance actions as a separate section of the PAR form. Section in under this program lists task statements required of the rating which are not reflected in the PQS qualifications. As PQS qualifications are de- veloped, PAR forms will be revised. The Record of Practical Factors will re- main in effect until 1 January 1977, at which time the PAR form will become effective. PAR forms are stocked in the Navy Supply System . Personnel Qualification Standards Personnel Qualification Standards (PQS) , de- scribed in OPNAV Instruction 3500.34, are presently being utilized to provide guidelines in preparing for advancement and qualification to operate specific equipment and systems. They are designed to support the advancement re- quirements as stated in the "Quals" Manual. The occupational standards and Personnel Advancement Requirements are stated in broad terms. Each PQS is much more specific in its questions that lead to qualification. It provides an analysis of specific equipment and duties, assignments, or responsibilities which an individ- ual or group of individuals (within the same rat- ing) may be called upon to carry out. In other words, each PQS provides an analysis of the complete knowledge and skills required of that rating tied to a specific weapon system (air- craft and/or individual systems or components). Each qualification standard has four main subdivisions in addition to an introduction and a glossary of PQS terms. They are as follows: 100 Series — Theory 200 Series — System 300 Series — Watchstations (duties, assign- ments or responsibilities) 400 Series — Qualification cards The introduction explains the complete use of the qualification standard in terms of what it will mean to the user as well as how to use it. The Theory (100 Series) section specifies the theory background required as a prerequisite to the commencement of study in the specific equipment or system for which the PQS was written. These fundamentals are normally taught in the formal schools (Preparatory, Fundamen- tals, and Class A) phase of an individual's training. However, if the individual has not been to school, the requirements are outlined and referenced to provide guidelines for a self- study program. The Systems (200 Series) section breaks down the equipment or systems being studied into functional sections. PQS items are essen- tially questions asked in clear, concise state- ment (question) form and arranged in a standard format. The answers to the questions must be extracted from the various maintenance manuals covering the equipment or systems for which the PQS was written. This section asks the user to explain the function of the system, to draw a simplified version of the system from memory, and to use this drawn schematic or the schematic provided in the maintenance man- ual while studying the system or equipment. Emphasis is given to such areas as maintenance management procedures, components, component ( 8 Chapter 1 — AEROGRAPHER'S MATE RATING parts, principles of operation, system interrela- tions, numerical values considered necessary to operation and maintenance, and safety pre- cautions. The Watchstation (300 Series) section in- cludes questions regarding the procedures the individual must know to operate and maintain the equipment or system. A study of the items in the 200 series section provides the individual with the required information concerning what the system or equipment does, how it does it, and other pertinent aspects of operation. In the 300 series section, the questions advance the qualification process by requiring answers or demonstrations of ability to put this knowledge to use or to cope with maintenance of the sys- tem or equipment. Areas covered include nor- mal operation; abnormal or emergency operation; emergency procedures which could limit damage and/or casualties associated with a particular operation; operations that occur too infrequently to be considered mandatory performance items; and maintenance procedures/instructions such as checks, tests, repair, replacement, etc. The 400 Series section consists of the quali- fication cards. These cards are the accounting documents utilized to record the individual's satisfactory completion of items necessary for becoming qualified in duties assigned. Where the individual starts in completing a standard will depend on his assignment within an activity. The complete PQS should be given to the individual being qualified so that he can utilize it at every opportunity to become fully qualified in all areas of his rating and the equipment or system for which the PQS was written. Upon transfer to a different activity, each individual must requalify. The answers to the questions asked in the qualification standards may be given orally or in writing to the supervisor, the branch or division officer, and maintenance officer as required to certify proper qualifica- tion. The completion of part or all of the PQS provides a basis for the supervising petty officer and officer to certify completion of the PQS section of the PAR (if applicable). Bibliography for Advancement Study The Bibliography for Advancement Study, NAVEDTRA 10052 (Series), is a very important publication for anyone preparing for advance- ment. This bibliography lists required and rec- ommended Rate Training Manuals and other reference material to be used by personnel working for advancement. NAVEDTRA 10052 is revised and issued once each year by the Naval Education and Training Support Command. Each revised edition is identified by a letter following the NAVEDTRA number. When using this publication, be sure that you have the most recent edition. If extensive changes in qualifications occur between the annual revisions of NAVEDTRA 10052, a supplementary list of study material may be issued in the form of a BUPERS Notice. When you are preparing for advancement, check with your Educational Services Officer or your Training Petty Officer to see whether changes have been made in the qualifications. If changes have been made, see if a BUPERS Notice has been issued to supplement NAVEDTRA 10052. The required and recommended references are listed by rate level in NAVEDTRA 10052. If you are working for advancement to third class, study the material that is listed for third class. If you are working for advancement to second class, study the material that is listed for sec- ond class, and remember that you will also be examined on the references listed at the third class level. NOTE: Personnel preparing for advancement will be examined on the TOTAL BIBLIOGRAPHY. Publications listed for a given paygrade fre- quently make specific reference to other publi- cations. These specific referrals are part of the TOTAL BIBLIOGRAPHY. Emphasis must be placed on the military/technical TOTAL BIBLIOGRAPHY for each paygrade; examina- tions are based on it. In using NAVEDTRA 10052, you will notice that some Rate Training Manuals are marked with an asterisk (*). Any manual marked in this way is MANDATORY — that is, it must be completed at the indicated rate level before you are eligible to take the Navy-wide exami- nation for advancement. Each mandatory man- ual may be completed by passing the appropriate Nonresident Career Course that is based on the mandatory training manual; passing locally pre- pared tests based on the information given in the training manual; or in some cases, success- fully completing an appropriate Class A School. Do not overlook the front section of NAVEDTRA 10052 which lists the required and AEROGRAPHER'S MATE 3 & 2 recommended references relating to the military standards/requirements for advancemt,.--t. For example, all personnel must complete the Rate Training Manual, Military Requirements for Petty Officer 3 & 2, NAVPERS 10056 (Series), for the appropriate rate level before they can be eligible to advance. The references in NAVEDTRA 10052 which are recommended, but not mandatory, should also be studied carefully. All references listed in NAVEDTRA 10052 may be used as source material for the written examinations at the appropriate rate levels. Rate Training Manuals There are two general types of Rate Train- ing Manuals. Rating manuals (such as this one) are prepared for most enlisted rates, giving information that is directly related to the pro- fessional qualifications. Basic manuals give in- formation that applies to more than one rate and rating. Basic Electricity, NAVPERS 10086 (Series), is an example of a basic manual be- cause many ratings use it for reference. Rate Training Manuals are revised from time to time to keep them up to date techni- cally. The revision of a Rate Training Manual is identified by a letter following the NAVEDTRA number. You can tell whether any particular copy of a Rate Training Manual is the latest edition by checking the NAVEDTRA number and the letter following this number in the most recent edition of List of Training Manuals and Correspondence Courses, NAVEDTRA 10061 (Series). NAVEDTRA 10061 is a catalog that lists current training man- uals and correspondence courses; you will find this catalog useful in planning your study pro- gram. Rate Training Manuals are designed to help you prepare for advancement. The following suggestions may help you to make the best use of this manual and other Navy training publications when you are preparing for ad- vancement. 1. Study the military requirements and the professional qualifications for your rate before you study the training manual, and refer to the occupational standards frequently as you study. Remember, you are studying the training man- ual in order to meet these occupational stand- ards. 2. Set up a regular study plan. If possible, schedule your studying for a time of day when you will not have too many interruptions or distractions. 3. Before you begin to study any part of the training manual intensively, become familiar with the entire manual. Read the preface and the table of contents. Check through the index. Look at the appendixes. Thumb through the manual without any particular plan, looking at the illustrations and reading bits here and there as you see things that interest you. 4. Look at the training manual in more detail to see how it is organized. Look at the table of contents again. Then, chapter by chap- ter, read the introduction, the headings, and the subheadings. This will give you a clear picture of the scope and content of the manual. As you look through the manual in this way, ask yourself some questions: What do I need to learn about this? What do I already know about this? How is this information related to information given in other chapters? How is this information related to the occupational standards? 5. When you have a general idea of what is in the training manual and how it is organized, fill in the details by intensive study. In each study period, try to cover a complete unit— it may be a chapter, a section of a chap- ter, or a subsection. If you know the subject well, or if the material is easy, you can cover quite a lot at one time. Difficult or unfamiliar material will require more study time. 6. In studying any one unit— chapter, sec- tion, or subsection— write down the questions that occur to you. Many people find it helpful to make a written outline of the unit as they study, or at least to write down the most im- portant ideas. 7. As you study, relate the information in the training manual to the knowledge you al- ready have. When you" read about a process, a skill, or a situation, try to see how this in- formation ties in with your own past experi- ence. 8. When you have finished studying a unit, take time out to see what you have learned. Look back over your notes and questions. Maybe some of your questions have been answered, 10 Chapter 1 — AEROGRAPHER'S MATE RATING but perhaps you still have some that are not answered. Without referring to the training manual, write down the main ideas that you have learned from studying this unit. Do not quote the manual. If you cannot give these ideas in your own words, the chances are that you have not really mastered the information. 9. Use Nonresident Career Courses (NRCC) whenever you can. These courses are based on Rate Training Manuals or on other appropriate texts. As mentioned before, completion of a mandatory Rate Training Manual can be ac- complished by passing a Nonresident Career Course based on the Rate Training Manual. You will probably find it helpful to take other courses in addition to those based on mandatory training manuals. Taking a Nonresident Career Course helps you to master the information given in the training manual, helps you to see how much you have learned, and can serve for refresher study. 10. Think of your future as you study Rate Training Manuals. You are working for ad- vancement to third class or second class right now, but someday you will be working toward higher rates. Anything extra that you can learn now will help you. Nonresident Career Course The Nonresident Career Course (NRCC), formerly called Enlisted Correspondence Course, for this Rate Training Manual (RTM) has been included at the back of the manual. Its pur- pose is to assist you in the training necessary to fulfill your job and advancement require- ments; it will be of benefit to you when pre- paring for the Navy-wide Advancement Examinations; and it reflects the more important information in the manual. Included in the course are learning objec- tives which state knowledges you will acquire by choosing the correct answer to each question or by restudying until you can choose the correct answer. The questions are teaching tools that point out important things in the Rate Training Manual. The Nonresident Career Course is an important part of the training package presented within these covers. The answer sheets to the NRCC, referred to as IKOR (immediate knowledge of results) sheets, are a separate package and are not included with this Rate Training Manual. A separate errata sheet may be included with this training package. If present, it will inform you of any changes in the text of the RTM or the NRCC. For complete instructions on this NRCC, read the preliminary pages thor- oughly before you proceed with the course. QUALIFYING FOR ADVANCEMENT In general, to qualify (be considered) for advancement, you must: 1. Have a certain amount of time in your present pay grade. 2. Demonstrate knowledge of material in your mandatory Rate Training Manual by making a suitable score on your command's test on the manual, by successfully completing the NRCC on the manual, or, in some cases, by graduating from an appropriate Navy school. 3. Complete the Personnel Advancement Re- quirement (PAR) form, NAVPERS 1414/4. 4. Be recommended by your commanding officer, after the petty officers and officers supervising your work have indicated that they consider you capable of performing the duties of the next higher rate by recommending you for advancement to the commanding officer. 5. For petty officer third and second candi- dates only, demonstrate knowledge of military subjects by passing the MILITARY/LEADERSHIP examination based on the military occupational standards for advancement from NAVPERS 18068 (Series). In addition to these requirements, to qualify for advancement you must demonstrate an under- standing of the technical aspects of your rate by passing a Navy-wide advancement examina- tion based on the occupational standards ap- plicable to your rate (from NAVPERS 18068 (Series), those occupational standards listed at or below your rate level). If you meet all of the above requirements satisfactorily, you are in a group from which advancements will be made. 11 AEROGRAPHER'S MATE 3 & 2 WHO WILL BE ADVANCED? Advancement is not automatic. Meeting all of the requirements makes you eligible but does not guarantee your advancement. Some of the factors that determine which persons, out of all of those qualified, will actually be advanced in rate are the score made on the advancement examination, the length of time in service, the performance marks earned, and the number of vacancies being filled in a given rate. If the number of vacancies in a given rate exceed the number of qualified personnel, then all of those qualified will be advanced. More often, the number of qualified people exceeds the vacancies. When this happens, the Navy has devised a procedure for advancing those who are best qualified. This procedure is based on combining the three following personnel evaluation systems: 1. Merit rating system (Annual evaluation and CO. recommendation) 2. Personnel testing system (Advancement examination score — with some credit for pass- ing previous advancement exams) 3. Longevity (seniority) system (Time in rate and time in service) Simply, credit is given for how much the individual has achieved in the areas of per- formance, advancement test, and seniority. A composite, known as the final multiple score, is generated from these three factors. All of the candidates who have PASSED the examina- tion from a given advancement population are then placed on one list. Based on the final multiple score, the person with the highest multiple score is ranked first, and so on, down to the person with the lowest multiple score. For candidates for E-4, E-5, and E-6, ad- vancement authorizations are then issued, be- ginning at the top of the list, for the number of persons needed to fill the existing vacan- cies. Candidates for E-7 whose final multiple scores are high enough will be designated PASS SELBD ELIG (Pass Selection Board Eligible). This means that their names will be placed before the Chief Petty Officer Selection Board, a BUPERS board charged with considering all so-designated eligible candidates for advance- ment to CPO. Advancement authorizations for those being advanced to CPO are issued by this board. Who, then, are the individuals who are ad- vanced? Basically, they are the ones who achieved the most in preparing for advancement. They were not content to just qualify; they went the extra mile in their training, and through that training and their work experience they developed greater skills, learned more, and accepted more responsibility. While it cannot guarantee that any one person will be advanced, the advancement system does guarantee that all persons within a particular rate will compete equally for the vacancies that exist and that the best qualified persons will be advanced. EXAMINATION PROCEDURES Examinations are given to candidates for advancement to E-4 through E-6 in February and August each year, E-7 through E-9 exams are given only once a year. The time and place of the examinations will be published in the Plan of the Day and in your station or unit paper. You must appear at the designated time and place in the uniform of the day and with your I D card. If you are to take the exam for AG3, no other person taking that exam will sit near you. This helps ensure that all taking the exam have an equal chance. The examiner or a proctor will read to you the instructions to be followed. Be sure you listen to and follow these instructions carefully. You will have three hours. Each question on the exam will have four possible answers from which to choose the correct one. Read each question carefully and all of the possible an- swers. If you know the correct answer, mark your answer sheet. If you do not know the answer, go to the next question. This will en- sure that you have time to answer all the ques- tions to which you know the answers in the time allotted. Each time you mark the answer sheet make your mark in the same number as the question. After you have gone through the exam and answered all the questions to which you know the answers, go through the exam again and answer the questions that you can limit to 12 Chapter 1 — AEROGRAPHER'S MATE RATING two probably correct answers. Then you can spend the remaining time considering the ques- tions about which you have the least knowledge and checking the questions and answers you have already completed. When the allotted time has passed, the proctor will collect the ex- amination booklets and the answer sheets. SUBJECT-MATTER SECTION IDENTIFICATION SHEET The Subject-Matter Section Identification Sheet (fig. 1-3) is a tear-out sheet included in your Navy-wide advancement examination book- let. It is to be detached from the examination booklet upon completion of the examination and given to the exam proctor. This sheet indicates the subject-matter sections of the examination which represent the occupational requirements for the rate. The occupational standards used to support the examination questions are also indicated for each subject-matter section. This sheet will be retained by the Educational Ser- vices Officer (ESO) for purposes of command review upon receipt of the Profile Analysis Form. Both of these forms will be made avail- able to you for your review at a date sub- sequent to the date of examination. PROFILE ANALYSIS FORM The Profile Analysis Form (fig. 1-4) is provided to all candidates two or three months after competing in the Navy-wide advancement examination. Normally, this form will be made available to you by your ESO with the Sub- ject-Matter Section Identification Sheet, pre- viously discussed. The Profile Analysis Form is to be used in conjunction with the Subject- Matter Section Identification Sheet to indicate your strengths and weaknesses for the particu- lar examination in which you competed. The Profile Analysis Form (refer to fig. 1-4) indicates the candidate's relative standing in Section 1 of the examination as being "A" (Average-middle). Section 1, as indicated on the Subject-Matter Section Identification Sheet, dealt with questions relating to "Surface Observa- tions." You can, therefore, conclude that your standing was average, in comparison with the rest of the candidates, for Section 1 of the examination, "Surface Observations". The oc- cupational standards used to support the ques- tions on "Surface Observations" were C1.01 and C2.01. The same procedure should be followed for the remaining sections of the ex- amination. By the use of these two forms you will be able to determine those areas where additional study could assist you in future examinations. SOURCES OF INFORMATION One of the most useful things you can learn about a subject is how to find out more about it. No single publication can give you all the information you need to perform the duties of your rating. You should learn where to look for accurate, authoritative, up-to-date informa- tion on all subjects related to the military re- quirements for advancement and the professional standards of your rating. Some of the publications described in this manual are subject to change or revision from time to time— some at regular intervals, others as the need arises. When using any publica- tion that is subject to change or revision be sure that you have the latest edition. When using any publication that is kept current by means of changes, be sure you have a copy in which all official changes have been made. Studying canceled or obsolete information will not help you perform efficiently or to advance; it is likely to be a waste of time, and may even be seriously misleading. TRAINING FILMS Training films available to naval personnel are a valuable source of supplementary in- formation on many technical subjects. Train- ing films are listed in the United States Navy Film Catalog, NAVAIR 10-1-777 (formerly NAVWEPS 10-1-777), published in 1969. Copies of this catalog may be ordered in accordance with the Navy Stock List of Forms and Publi- cations, NAVSUP 2002. Monthly supplements to the Film Catalog are distributed to catalog holders. Check with your Training Petty Officer for the location of the nearest Film Catalog. When selecting a film, note its date of issue listed in the Film Catalog. As you know, pro- cedures sometimes change rapidly; thus, some films become obsolete rapidly. If a film is obsolete only in part, it may still be of some use. 13 AEROGRAPHER'S MATE 3 & 2 GIVE THIS SHEET TO YOUR PROCTOR FOR THE AG3/2 EXAM EIAM HMF©MMIATn©S! SUBJECT-MATTER SECTION IDENTIFICATION THESF Ql ALIFICATIONS ARE FROM THE MANUAL OF QUALIFICATIONS FOR ADVANCEMENT NAVPERS I8068( ) INCLUDING CHANGE ( ) TW BASIC BIBUOCMFHT FOR THIS EIUIMTIOI IS CONTAIHEO IN HIUOtjAPHt Fflj MVAjCgllffT STUDT (NAVEDTRA 10092 - W) FOR ALL EXAMINATIONS WITH SERIAL NUMBERS FROM 730001 TO 739999 s 1. This examination was divided into SUBJECT-MATTER SECTIONS. The titles of these sections are general in nature and represent the occupational requirements of this rate . The chart below shows both the sectional breakdown for THIS examination and the qualifications from The Manual of Qualifications for Advancement (NavPers 18068-C) used to support the questions. 2 . The basic biblioqraphy for THIS examination is contained in Bibliography for Advancement Study (NAVEDTRA 10052-W) . It should be remembered that the publications listed for a given rating and paygrade may have suggested reading lists or may make specific references to other publications. These reading lists and other specific referrals must be considered as part of the TOTAL bibliography. 3. This SUBJECT-MATTER SECTION IDENTIFICATION SHEET is to be used with the PROFILE ANALYSIS FORM (explained on the back of this sheet) to identify a candidate's strengths and weaknesses in terms of subject-matter for this particular examination. 4. USNR-R usage of the PROFILE ANALYSIS FORM 1= vered by separate correspondence. o < 111 EXAMINATION SU»JECT-MATTE« SECTION QUALIFICATIONS SUPPORTING THE QUESTIONS SECTION TTHE (FROM NAVPERS 18068) 1 SURFACE OBSERVATIONS CI. 01, C2.01 2 SPECIAL OBSERVATIONS C2.02, C2.03 3 SURFACE CODES AND PLOTTING D1.01, D1.03, D2.01, D2.02 4 UPPER AIR CODES AND PLOTTING 01.02, D1.04, D1.05, D2.01, D2.02 5 COMMUNICATIONS EQUIPMENT B1.01, B1.02, B2.01 6 OBSERVATIONAL INSTRUMENTS AND EQUIPMENT A1.01, B1.03, B2.02 7 METEOROLOGY AND OCEANOGRAPHY CI. 04, F2.01, F2.02, F2.03 8 SPECIAL PHENOMENA F2.01, F2.03 9 COMMUNICATIONS B2.04 f F TO BASIC MILMCUMI F0« THIS EXAMIHATIOH IS COMTAIMEO III BIBLIOGRAPHY FOB ADVABCEWEBT STUDY (NAVEDTRA 10052-W) THIS SHEET MUST BE USED WITH THE MANUAL OF QUAUFICATIONS FOR ADVANCEMENT (NAVPERS 18068) Figure 1-3. — Subject-matter section identification sheet. 209.390 14 Chapter 1 — AEROGRAPHER'S MATE RATING DEPARTMENT OF THE NAVY NAVAL EDUCATION AND TRAINING PROGRAM DEVELOPMENT CENTER . _„ ,,- PENSACOLA. FLORIDA 32909 FROM: COMMANDING OFFICER SERIAL/DATE jo, (YOUR NAME WILL APPEAR HERE) ACTIVITY COOE 12345 AB SUBJ: EXAMINATION PROFILE INFORMATION (YOUR EXAM SERIAL NUMBER AND THE DATE WILL APPEAR HERE) THE INFORMATION PROVIDED BELOW IS A PROFILE OF YOUR RELATIVE STANDING WITH ALL OTHERS IN YOUR RATE IN EACH SUBJECT-MATTER SECTION. THE INFORMATION IS TO BE USED WITH THE SUBJECT-MATTER IDENTIFICATION SHEET FOR THE E XAMINATION SERIAL INDICATED STANDINGS ARE BASED ON OVER 90* RETURNS; NO SIGNIFICANT CHANGE WITH ALL RETURNS IN. EXAMINATION STATUS YOUR FINAL MULTIPLE © minimum/^ MULTIPLES, REQUIRED © D S'SECTION 1 2 3 4 s 6 7 ( ♦ 10 •1 12 © STANDING A A HA L p LA P A E COPY TO SERVICE RECORD COOE INTERPRETATION S (Sup-rip,) =gpp., 10* E (E«c.ll.rtt) = upper 20% H > **, «SB, Ojjf %. S, ftr * Ifc. C ' r 'C DENSITY ALTITUDE COMPUTER _,L * FSN 6660-955-087} CONTRACT NO N00383-73-C CP-7I8/UM MFR-S P/N FAS-54 FUSENTHAl INSTRUMENTS CHICAGO, III. 60656 CO 209.380 Figure 2-12,-Density altitude computer CP-718/UM. 31 AEROGRAPHER'S MATE 3 & 2 speed, rate of climb, and fuel consumption, but also plays an important role in determining the length of runway necessary for takeoff. The Density Altitude Computer CP-718/UM consists of two plastic or metal discs and one cursor. The bottom disc contains the temperature expressed in Celsius and Fahrenheit, while the top disc contains the pressure density, moisture correction, and dry bulb temperature scales. On the cursor is found a wet bulb temperature scale. The computer was primarily designed to compute atmospheric density. It may, however, also be used to interconvertthermometric scales, pressure units, density ratio, vapor pressure, specific humidity, etc. The operating instructions are printed on the back of the computer. (See fig. 2-12.) MAINTENANCE The important points in regard to calcula- tors, computers, and evaluators are the cleaning and storing of them. The pointers listed in this section apply to all the computers in use in the Naval Weather Service, such as the psy- chrometric computer, true wind computer, mixing ratio calculator, and the like. To remove accumulations of dirt, dust, and lint from the spaces between the plates and under the cursor, draw a piece of paper through the space while applying a slight pressure to the discs or cursor. If grease or gummy deposits are present, moisten a blotter with soap and water and proceed as above. Exposed surfaces may be cleaned with a soft cloth, soap, and water. Rinse thoroughly and dry. DO NOT USE SOLVENTS. Plastic calculators, computers, and evaluators should be returned to their original packaging preparatory to storage or shipment. If the original packaging is no longer available, an equivalent method will suffice. The items should not be stored in any atmosphere in which the tem- perature exceeds 140° F. NOTE: Changes to all column numbers and entries on NWSC Form 3140/8 were received too late for inclusion in this manual. Where errors in column numbers appear, refer to the U.S. Navy Supplement to FMH #1, Chapter 13, Marine Aviation Observations for the most recent ampli- fying instructions. 32 CHAPTER 3 WIND EQUIPMENT The usual point for taking observations is at the surface of the earth. When we refer to the weather element "wind," we are speaking of "surface wind." This chapter will deal with various types of equipment used in measuring wind, methods of observing, procedures for recording, requirements for maintenance, and wind computers. You will find a discussion on the various facets of wind, in chapters 12, 13, 14, and 15. Upper winds and their associated measuring equipments are briefly discussed in chapters 9 and 10 of this manual. WIND Wind is air in motion. As air in motion, the wind has four important properties of vital interest to us: direction, speed, character, and shifts. The character of the wind refers to its gustiness and the like; the shifts of the wind refer to its steadiness or unsteadiness in direction. DEFINITIONS Wind definitions are as follows: 1. Wind direction. Wind direction is the direction FROM which the wind is blowing. It is reported with reference to true north, and is expressed to the nearest 10 degrees or to 16 points of the compass. 2. Wind speed. Wind speed is the rate of motion of the air in a unit of time. Wind speed can therefore be measured in a number of ways. The Naval Weather Service measures the speed of the wind in knots; that is, it measures the wind in nautical miles per hour. 3. Gust. Gust is defined as rapid fluctuations in wind speed with a variation of 10 knots or more between peaks and lulls. 4. Squall. Squalls are defined as a sudden increase in wind speed of at least 15 knots and sustained at 20 knots or more for at least 1 m'nute. The occurrence of squalls is indicative of turbulence near the surface. 5. Peak gust. The highest instantaneous wind speed observed or recorded. 6. Wind shifts. "Wind shift" is a term applied to a change in wind direction of 45° or more which takes place in less than 15 minutes. Wind shifts are normally associated with some or all of the phenomena characteristic of a cold-frontal passage. These phenomena are: a. Gusty winds shifting in a clockwise manner in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. b. Rapid drop in dewpoint. c. Rapid drop in temperature. d. Rapid rise in pressure. e. In summer: lightning, thunder, heavy rain, and possibly hail. f. In winter: frequent rain or snow showers. Changes of wind direction may also result from other causes such as katabatic or foehn winds, sea breezes, and thunderstorms. In such cases, the change of direction may be gradual or abrupt, and may or may not be accompanied by significant changes of other weather elements. Wind shifts are reported when believed to be associated with frontal movement, or when considered important for the safety of aircraft operations. 7. Variable wind direction. Wind direction is considered to be variable when it fluctuates by 60° or more during the period of observation. 33 AEROGRAPHER'S MATE 3 & 2 8. Light wind. The wind is considered to be light when the speed is six knots or less. WIND MEASUREMENTS There are four qualities of the wind that the observer must determine; they are wind direction, wind speed, character, and shifts. Instructions for determining these qualities of the wind are contained in the following para- graphs. The instruments used by the Navy are the direct reading type (indicating or recording) and are described later in this chapter. Wind Direction Wind direction is observed for a 1-minute interval with reference to true north and in 10°-increments in a clockwise direction from true north. When the air is not in motion, the wind is said to be CALM. When instruments for measuring the wind direction are not avail- able or are inoperative, estimate the direction by observing a wind cone or tee, movement of trees, smoke, or by facing into the wind in an unsheltered area. Do not use the movement of clouds, regard- less of how low the clouds are, in estimating the surface wind direction. Wind Speed Determine speed of the surface wind to the nearest knot. In general, observed wind speeds are a 1-MINUTE AVERAGE. So far as possible, the average wind speed observation should not be made during a peak or lull in gusty winds or squalls. Where wind speed instruments are tem- porarily unrepresentative or not available, estimated speed (including gustiness and squall data) may be determined by use of Appendix VI. Character and Shifts The character and shifts of the wind are determined by examining the wind speed indicator/ recorder to determine if the required criteria have been met to report the phenomena. FORMS Several types of forms are used to record wind data. Some were previously mentioned, such as the MF1-10 shore form, and the NWSC 3140/8 ship form, also recording rolls for the UMQ-5( ) and GMQ-29( ). MF1-10 Entries Although the following descriptions of wind element entries are correct, they are brief and the Aerographer should refer to the Federal Meteorological Handbook No. 1 for a more complete and detailed description of the proper procedures. WIND DIRECTION (COL . 9) . — Enter the wind direction to the nearest tens of degrees. Use 2 digits as shown in table 3-1. Enter "00" when the wind is calm. Whenever either the reported wind direction, speed, speed of gusts or squalls is estimated, prefix the direction with an WIND SPEED (COL. 10). — Enter the wind speed in knots. For calm wind enter "00". When the speed exceeds 99 knots, enter only the tens and units figures and add 50 to the wind direction in column 9; e.g., 112 knots from 270° 7712. WIND CHARACTER (COL. 11). — Enter gusts by using the symbol "G" followed immediately by the peak speed of gusts observed during the past 10 minutes. Report squalls by the symbol "Q" followed immediately by the peak squall wind observed during the past 10 minutes. These are reported when they occur regardless of the type of wind equipment utilized. WIND SHIFTS AND VARIABLE WIND DATA (COL. 13). — A wind shift is always reported when it occurs. To report a wind shift, enter in column 13 the contraction "WSHFT" followed by the time the wind shift began in minutes past the hour using two digits (e.g., WSHFT 37). When the shift is reasonably certain to be associated with a frontal passage, include the contraction "FROPA" immediately after the time (e.g., WSHFT 37 FROPA). If the remark containing this data Is not transmitted via longline teletype, the data will then be included 34 Chapter 3 — WIND EQUIPMENT Table 3-l.-Wind direction in tens of degrees Compass Tens of Degrees Points degrees 355-004 N 36 005-014 01 015-024 NNE 02 025-034 03 035-044 04 045-054 NE 05 055-064 06 065-074 ENE 07 075-084 08 085-094 E 09 095-104 10 105-114 ESE 11 115-124 12 125-134 13 135-144 SE 14 145-154 15 155-164 SSE 16 165-174 17 175-184 S 18 185-194 19 195-204 SSW 20 205-214 21 215-224 22 225-234 SW 23 235-244 24 245-254 WSW 25 255-264 26 265-274 W 27 275-284 28 285-294 WNW 29 295-304 30 305-314 31 315-324 NW 32 325-334 33 335-344 NNW 34 345-354 35 in the REMARKS section of the next transmitted report to be sent via longline teletype. When wind meets the criteria for variable wind, the contraction "WND" will be entered in column 13 followed by the extremes of variability and separated by the letter •'V" (e.g., WND 32V05). WIND SUMMARY DATA (COLS 71, 72 & 73). — A column 71 entry Is only made at stations having a continuous instantaneous wind- speed recorder. Enter in knots the highest instantaneous peak gust recorded during the 24 hours ending at midnight. Column 72 is for entry of the peak gust's direction to the nearest 10 degrees. If the direction portion of the record is missing or inoperative, estimate from the column 9 entries and enter to the 8 point compass. Column 73 is for the time of oc- currence of the maximum gust and is entered to the nearest minute LST. 35 AEROGRAPHER'S MATE 3 & 2 NWSC 3140/8 Entries WIND (COLS. 12, 13, & 14). — Enter the TRUE wind direction, wind speed (in knots), wind shifts, gustiness, and squalls in accordance with instructions for columns 9, 10, and 11 of MF1-10. The difference between land station wind observations and shipboard wind obser- vations is that compensation must be made for the ship's heading and speed, and true wind direction and speed have to be computed; they cannot be observed directly. Several methods for computing the true wind at sea are available. Two of these methods, the True Wind Computer CP-264/U and the True Wind Observing Method, will be discussed in detail later in the chapter. When wind indicating or recording equip- ments is inoperative or unavailable, estimate wind speeds in accordance with criteria listed in Appendix VI. This appendix may also be used to check computed wind speeds. Wind directions may be estimated by observing the direction of travel of sea waves. Remember that such directions are relative to the ship's heading, and they must be converted to true directions. SUMMARY OF THE DAY (COLS. 52 through 56). — Enter the maximum wind data for the period from midnight to midnight GMT. Enter estimated wind data if recording equipment is not available. In column 52, enter times to the nearest minute GMT. In columns 53 and 54, enter the positions to the nearest whole degree latitude and longitude. In columns 55 and 56, wind direction and speed is entered as it was entered in columns 12 and 13 of NWSC 3140/8. Directly beneath these column entries, space is provided for entries of gale conditions or greater (34 kns or higher) if the ship is steaming north of 30°N. or south of 30°S. If the ship is steaming between 30°N. and 30°S., make entries in these columns if the wind is 22 knots or greater. Wind Recorder Charts Wind recorder charts from the RD-108/ UMQ-5 and GMQ-29 recorders are handled in the following manner: 1. At the beginning and end of each chart roll, enter station name (NAS, etc.), date and time that record began/ended, and chart feed rate if different from normal, or if times are not printed on the chart. 2. Change charts at 0000 LST on the first day of each month and at intermediate times as necessary to prevent loss of record. 3. Replace charts in original shipping carton if available, and enter the station name and period of record on the end of the carton. Forward completed charts monthly in accord- ance with instructions in chapter 11 of this training manual. 4. Power and equipment failure is indicated on the recorder chart by entering the term "POWER FAILURE" or "EQUIPMENT FAIL- URE" at the point of failure, along with the time (LST) of the failure. When returned to service, the chart should be adjusted to the correct time and a time check entered. WIND MEASURING SET AN/PMQ-3( ) OPERATION Wind Measuring Set AN/PMQ-3, -3A, -3B, and -3C is a portable hand anemometer. It is a combination wind direction and speed indicating unit which indicates direction to 360° and speed from to 60 knots. The wind, upon striking the small cylindrical turbine (fig. 3-1) in the transmitter causes the turbine to rotate. The turbine is linked to a small electrical generator which produces a voltage proportional to the speed of the turbine. The voltage is transmitted to the indicator, which is a voltmeter graduated in knots. The indicator has 2 scales, graduated from to 15 knots and from to 60 knots. The upper trigger on the handle controls the scale to be used. The direction unit is a twin-tailed assembly with a pointer (vane nose), which faces into the wind, when the brake is released by depressing the vane locking trigger. The index pointer on the vane is then aligned on the direction dial with the direction from which the wind is blowing. To make an accurate direction reading, follow this procedure: a. Choose a location where there will be, as nearly, as possible, unobstructed wind flow from all directions. 36 Chapter 3 — WIND EQUIPMENT BRAKE JAM NUTS VANE NOSE VERTICAL EXTENSION TUBE HOUSING COVER RANGE SELECTING TRIGGER DIRECTION SIGHT VANE LOCKING TRIGGER WIND SPEED TRANSMITTER T-32IB/PMO-3 SCREWS MOUNTING HUB WIND VANE ML-447B/PM0-3 SCREW WIND SPEED INDICATOR ZERO ADJUSTMENT HANDLE , 09.122 Figure 3-1. — Wind Measuring Set AN/PMQ-3( ). b. Grasp the instrument by the handle and hold It in an approximately vertical position at arm's length with the sight at eye level. c. Aim the instrument at a fixed orientation point by aligning the center of the slot in the front of the sight with the center of the strip between the two slots on the rear sight and the fixed orientation point. d. Press and hold the vane locking trigger. Note the reading on the 0-60 (upper) scale on the wind speed indicator. e. If the wind speed reading is less than 15 knots as indicated on the 0-60 scale, press the range selecting trigger on the side of the housing (3B and 3C models) or handle (3 and 3A models) and observe the indication on the 0-15 scale. CAUTION: The range selecting trigger should not be pressed if the initial observation of the wind speed indicator indicates a wind speed in excess of 15 knots as mechanical damage may result due to the slamming of the pointer. f. The instant the wind speed indication is noted, release the vane locking trigger and carefully lower and tilt the instrument to observe the wind direction reading on the direction dial. CAUTION: After the vane locking trigger is released, care must be taken not to disturb the vane's position until the direction reading is made. g. Observe the wind direction reading in whole degrees and then record both the wind direction and speed readings. 37 AEROGRAPHER'S MATE 3 & 2 The equipment is issued ready for use and comes stowed in a carrying case containing a spare wind speed transmitter and a spare wind vane. The instrument should always be replaced in this carrying case after use. Special care should be taken in removing the anemom- eter from the case and replacing it in the case because damage may easily result to the wind vane section. MAINTENANCE In the care and maintenance of Wind Measuring Set AN/PMQ-3( ), no special service tools are needed. In inspecting the equipment, make certain that the turbine and vane are free to rotate and that there is pointer move- ment when the turbine is rotated. Check for freeness by holding the instrument in its operating position and walking at a moderate rate of speed in an area where there is no air movement. If the vane assumes the correct position and there is a speed indication on both scales, it is probable that the instrument is in a satisfactory condition. If trouble develops in the system, refer to table 3-2. This table lists troubles, along with possible causes, and their remedies. Procedures to replace or repair a component when found to be malfunctioning are as follows: 1. Wind speed transmitter. — To replace the wind speed transmitter (fig. 3-1), grasp the transmitter by its cover (never the cage) and give it a slight twist in a counterclockwise direction (looking down on the instrument) and pull it straight off. Remove the spare transmitter from the case in a like manner. Install the spare transmitter by reversing the above pro- cedure, making sure that the unit is securely locked in position. 2. Wind speed indicator. — See technical manual (NA50-PMQ3C-1) for details of pro- cedure. If physical damage is not visible, and as a defective indication may be caused by another component, do not discard the unit until its condition has been proved unsatisfactory by a requisitioned replacement. 3. Trigger and switch assembly. — See tech- nical manual (NA50-PMQ3C-1) for details of procedure. If physical damage is not visible, and as a defective indication may be caused Table 3-2.— Troubles and remedies (wind speed system— AN/PMQ-3( )) Trouble Probable cause Remedy No pointer movement 0-60 range or 0-15 range. Defective speed indicator. . . Replace detector. Replace indicator. No pointer movement 0-60 range only. Defective speed indicator. . . Replace indicator. No pointer movement 0-15 range only. Defective switch or defective speed indicator. Connect the terminals of the switch to- gether; if indication is obtained, replace trigger assembly. If no indication is ob- tained, replace indicator. Pointer does not rest on zero when turbine is stationary. Speed indicator not properly zeroed. Turn zero set adjust- ment located on the front of the indicator. Sluggish pointer movement. Dirty or damaged speed indicator. Replace indicator. 38 Chapter 3 — WIND EQUIPMENT by another component, do not discard this unit either until its condition has been proved unsatisfactory by a requisitioned replacement. 4. Wind vane. — Minor defects and dents are not cause for replacement. If twisted parts affect the accuracy, try to straighten them. If the vane is not repairable, the spare wind vane from the case should be installed (See technical manual (NA50-PMQ3C-1) for detailed pro- cedure.) and another wind vane requisitioned from stock spares. No lubrication or cleaning is required by the operator, except that the wind speed trans- mitter should be lubricated every 6 months or at any time the turbine appears to be running sluggishly. Check with your supervisor as to how to lubricate the transmitter; or in the absence of a supervisor, consult the handbook for the instrument. WIND MEASURING SET AN/UMQ-5( ) Wind Measuring Set AN/UMQ-5( ) (fig. 3-2) is the standard equipment designed to provide a visual indication and/or printed record of wind direction and speed values. Various options of the system are provided to permit continuous recording of wind direction and speed values at several measuring sites. COMPONENTS A set includes a minimum of one transmitter, one support, and one recorder or indicator. A maximum of six recorders and/or indicators can be used with each transmitter. Mounting Options Although the complete wind measuring set is illustrated in figure 3-2, various options in mounting the display components of the set are shown in figure 3-3. Transmitter ML-400( )/UMQ-5 The transmitter (fig. 3-2 (A)) is a vane mounted on a vertical support. The tail of the vane brings the nose into the wind. The nose consists primarily of a screw-type impeller directly coupled to a tachometer-magneto. The magneto voltage output is directly proportional to the wind speed and is connected to the plug in the transmitter's vertical support through brushes and sliprings, then down to the indicator or recorder whose voltmeter auto- matically indicates or records the voltage in knots. Motion of the vane is transmitted mechanically to a synchro located inside the enlarged section of the vertical support. The transmitter is placed on top of a con- nector housing. The electrical cable, leading from the housing through the support, goes to any one or all of any combination of six repeaters, whether all indicators or all recorders, or a combination of them. A follower synchro then converts the electrical energy into wind direction indication or recording. The transmitter is designed to carry six repeaters. Support MT-535/UMQ-5 The support (fig. 3-2(B)) is of the tripod- type design, having a tubular upright mast and three legs constructed of tubular steel tubing. Each leg is equipped with a mounting foot. The top of the support is provided with a clamp to hold the transmitter securely in place when mounted. Wires may be run through the center of the mast into the transmitter connector housing. The support may be tilted for servicing the transmitter. A guy plate is provided for the attachment of guy wires, if necessary. Another support may also be used with this system. It is very similar to the support shown in figure 3- 2(B) with only minor changes in fittings and provisions for conduit built into it. Indicator ID-300( )/UMQ-5 The ID-300( ) indicator (fig. 3-2(C)) consists of two units: the panel assembly and the mounting case which holds the panel assembly. The panel assembly contains the wind direction indicator and the wind speed indicator positioned in two 4-inch dials, the lighting circuits, and the double- range switch for the speed section. The wind direction indicator consists of a synchro follower on whose rotor shaft is mounted a pointer that indicates wind direction values on a 360°-circular scale. The dial is graduated at the cardinal and intercardinal compass points as well as every 5° from north. 39 AEROGRAPHER'S MATE 3 & 2 DIRECTION CASE INDICATOR SPEED INDICATOR PANEL ASSEMBLY . CONNECTOR HOUSING TAIL VANE DOUBLE -RANGE SWITCH CHART GUIDE- PEN LIFT MECHANISM DIRECTION MECHANISM SPEED MECHANISM DOOR CHART-DRIVE MECHANISM 209.119 Figure 3-2. — Wind Measuring Set AN/UMQ-5( ). (A) Transmitter ML-400( )/UMQ-5; (B) Support MT-535/UMQ-5; (C) Indicator ID-300( )/UMQ-5; (D) Recorder RD-108( )/UMQ-5; (E) In- dicator ID586( )/UMQ-5. 40 Chapter 3 — WIND EQUIPMENT CD CO z cr o LU 1- < < LU cc 0. LU LU a. ac o o to co o" o CN LU O u. DC u. LU o H < cr LU LU a. X LU 1- K < LU 5 CO G O •iH -t-> & G° •i-i ■s 3 O G O I o o CO I CO (L> & 41 AEROGRAPHER'S MATE 3 & 2 The wind speed indicator is a precision, high- shock type voltmeter whose pointer indicates wind speed in knots on a scale whose ranges are to 60 knots or to 120 knots. The scales are circular about an arc of approximately 270°. Selection of ranges is accomplished by the use of the double- range switch to change range from to 60 knots to to 120 knots. Indicator ID-586/UMQ-5 The ID-586 indicator (fig. 3-2(E)) consists of a speed indicator (voltmeter) and a direction indicator (synchro) mounted on a panel which is inserted in a case. A six-tapped dummy load register is attached to the terminal board mounted in the bottom of the case. No panel lighting or dual-range circuits are installed in this indicator. Each of the indicating as- semblies (speed and direction) is removable and may be installed individually. Indicators GMQ-29/UMQ-5 The UMQ-5( ) is also used to feed data on wind direction and wind speed into the new digital readouts of the AN/GMQ-29( ), Auto- matic Weather Station. This data is constantly displayed on the readout panel through a very complex system of electronic data reception and computations. This computer system is too detailed and complex for discussion in this manual. For further information on its theory of operation and application refer to NAVAIR 50-30GMQ-29-1. Recorder RD-108( )/UMQ-5 The RD-108( ) recorder (fig. 3-2(D)) bas- ically consists of a direction mechanism, speed mechanism, chart drive mechanism, chart guide-pen lift mechanisms, chart, and case. A description of each is given in the following paragraphs. WIND DIRECTION MECHANISM. — The wind direction mechanism consists of a synchro follower which positions the pen through a gear train which converts 540 wind degrees of synchro rotation to approximately 62° of pen rotation, corresponding to 540 wind degrees of the chart. Whevever wind conditions are such that the pen would run off the chart in recording wind direction, a repositioning mechanism is energized. This mechanism removes power from the synchro, drives the pen to the approximate center of the chart, and then returns power to the synchro so that recording is continued after the pen is displaced 360 wind degrees toward the middle of the chart. The direction inking system consists of the pen and a stationary ink tank. The pen is designed to fit into a pen holder attached to the synchro gear train and has a small tube which fits into the ink tank and feeds ink by capillary action to the penpoint which rests on the chart. WIND SPEED MECHANISM. — The wind speed mechanism consists of a voltmeter mechanism which drives the wind speed pen across the speed section of the chart. Also included in the speed section is a six-tapped dummy load resistor connected across a terminal board. The pen and inking system of the speed section is identical to that of the direction section. CHART DRIVE MECHANISM. — The chart drive mechanism is a removable, self-contained assembly, consisting of a frame and various mounted parts. The assembly contains the chart drive motor, drive gear train, drive roll, idler roll, chart trough, removable takeup reel, takeup motor, and hinged panel. Also mounted on the assembly are the speed change gears, chart drive ON-OFF switch, takeup motor mjcroswitch, and the plug through which power is introduced to the mechanism. When the mechanism is seated inside the recorder case and the chart drive switch is in the ON position, the chart drive motor moves the chart across the drive roll and under the pens at a rate determined by the change gears selected. The chart is rerolled on the takeup reel by the takeup motor. CHART GUIDE-PEN LIFT MECHANISM.— The chart guide-pen lift mechanism is an as- sembly which guides the chart across the drive roll, holds the chart drive mechanism in place, and provides a mounting for the illuminating lamps and the direction and speed scales. The assembly is pivoted so that it may be lifted to gai'- access to the chart drive mechanism and iru tanks, and to lift the pens off the chart. CHART. — The strip-type chart is divided into two main channels. The right channel is for the recording of wind speed and is graduated every 42 Chapter 3— WIND EQUIPMENT 2 knots from to 120 knots. The left channel is for the recording of wind direction and is graduated every 10° over a 540° range. Direction letters representing the cardinal compass joints (N-E-S-W-N-E-S) are printed above the appropriate numerical direction values. The chart is designed for use with the 3-inches-per-hour chart speed, and the time lines are graduated to 10 minutes and numbered every hour. Holes on either side and in the center of the chart provide positive drive between the chart and the sprocket drive roll. The chart has a running time of approximately 15 days. CASE. — The case is made of cast aluminum and has a hinged door. The door contains a plastic window large enough for viewing the indication scales, pens, and 7 inches of the past record. It also is provided with a rubber gasket to ensure a tight fit when the door is closed. A recess at the bottom rear of the case has connections for the power and inter- component cables. Recorder RO-447/GMQ-29 Figure 3-4. 209.361 -Analog Recorder RO-447/GMQ-29. This is an analog recorder (fig. 3-4) newly designed for use with the AN/GMQ-29( ), Auto- matic Weather Station, utilizing inputs from the UMQ-5( ) Wind System, through a complex system of electronic data reception and computations prior to being recorded. The recorder records wind direction, wind speed, and rainfall (discussed in chapter 4). It differs in its presentation of recorded data from the RD-108/UMQ-5 in that it records straight lines instead of curved lines, uses a different chart, and has different chart speeds. Presently it uses ink pens and tanks similar to the RD-108/ UMQ-5, but plans are for a changeover to a ballpoint-type pen in the near future. Main- tenance of this recorder is covered in chapter 4 under the AN/GMQ-29( ) Automatic Weather Station. Model Differences/UMQ-5 Transmitters ML-400B and ML-400C are identical to earlier models, except that they are larger in the synchro section to allow for the use of six repeaters. The ID-586 indicator has no predecessor. The ID-300B and ID-300C indicators are identical with older models with the exception of the resistance strip to allow for the adjust- ments needed when from one to six repeaters are used. The RD-108B and RD-108C recorders differ from earlier models primarily in the relay system to allow for the one to six repeaters running from the same transmitter. The recorder that is available with the AN/UMQ-5D has a pen stop arrangement that prevents the pen from catching in the center holes of the chart. OPERATION Installation of Chart Speed Change Gears The recorder is equipped with chart drive gears to give a chart speed of 3 inches per hour, which matches the time graduations of the chart supplied. (See fig. 3-5(A).) Change gears to provide a chart speed of 6 inches per hour or 1 l/2 inches per hour are mounted on a stud on the left side plate of the chart drive mechanism. The change gear arrangements 43 AEROGRAPHER'S MATE 3 & 2 (A) (B) DRIVE GEARS CHANGE GEARS TAKEUP REEL (C) DRIVE ROLL IDLER ROLL CHART SET KNOB I ■^ V)) s y f T^ kl CHART PATH \ mt^^k H TR0UGH J \ ^^"SUPPLY ROLL TVg) .TAKEUP REEL RIGHT SIDE (D) PIVOT SLOT KNIFE EDGE INK TANK 209.121 Figure 3-5. — Recorder RD-108( ) views. (A) Recorder chart drive mechanism (left side view); (B) chart threading diagram; (C) recorder chart drive mechanism (right side view); (D) filling ink tanks. given in the equipment handbook show the com- bination of gears to obtain the different rates of chart speed. To change the rate of chart speed, consult the equipment handbook. Installation of Chart Wind several turns of the tapered end around the takeup reel before installing the reel in the chart drive mechanism. Installation of Chart Drive Mechanism Install the chart according to figure 3-5(B). Cut the chart corners as shown in figure 3-5(A). Lift up the operation levers (fig. 3-5 (D)). Place the chart drive mechanism in the recorder 44 Chapter 3 — WIND EQUIPMENT so that the pivot slots (fig. 3-4 (C)) in the mechanism side plates are seated on the pivots mounted in the case. Return the mechanism to its normal operating position. Lower the operation levers over the chart drive roll. Installation of Ink Tanks and Pens Fill both ink tanks about three-fourths full through the pen opening; use the ink and ink tank filler furnished with the recorder as shown in figure 3- 5(D). Do not use standard writing inks. Keep the bottle tightly capped to prevent dirt from getting into the ink. Raise the scale plates and insert the ink tanks in the receptacles on top of the speed and direction mechanism assemblies and see that they are under the spring clips. Set the pen elements in the pen element forks (penholder) by seating the knife edges of the elements into the slots of the fork. NOTE: The ink tanks and pens may be installed or removed for servicing when the chart drive mechanism is removed, tilted for- ward, or is in its operating position. Zeroing Speed Pen With the chart drive mechanism installed and a chart installed in the drive mechanism, loosen the thumbscrew securing the speed pen zero adjustment lever and adjust the speed pen to read zero on the chart (not the scale). Disconnect the leads from the synchro follower for this adjustment. Filling Pens Fill the ink tank with the ink tank filler furnished with the recorder. Compress the bulb of the ink tank filler and lay the flat side of the soft rubber tip on the chart. Insert the penpoint into the hole in the rubber tip and let the filler suck in ink from the ink tank through the pen. The pen feeds from the ink tank by capillary action once it is filled. Remove the pen element from the filler. The pen should rest lightly on the chart. Swing the pen across the chart a few times. If it does not write properly, the pen probably has an air bubble in it, In which case the pen filling operation must be repeated. NOTE: Do not apply power to the recorder when the direction pen is being swung. Be sure that the pen is properly seated and that it does not rub on the ink tank. Also, check to see that it does not rub on the indication scales and the pen lift bar when they are in their operating positions. The indicating flag above the pen must not touch the scale plate. NOTE: The pen element is correctly balanced at the factory when full of ink and will stay off the chart until the pen is filled. Setting Chart to Time With the power cable connected and all power switches in the ON position, turn the chart set knob until the correct time line on the chart Is under the pens. (See fig. 3-5(C).) NOTE: After time setting the chart, do not tilt the chart drive mechanism forward; power supplied to the chart drive motors will be interrupted, thus losing the time setting. Unrolling Chart for Examination The chart record may be unrolled from the takeup reel while the chart mechanism is operating by grasping the chart on either side, near the takeup reel, and pulling the chart from the reel. Be careful to keep the chart straight and taut as it is allowed to rewind on the reel. Removing Chart From Takeup Reel Remove the chart from the takeup reel by first removing the reel from the recorder. Then pull the plain flanged end from the core of the reel. Slide the chart off the core. Transmitter and Indicators The transmitter requires no operating pro- cedures. The only operation necessary for Indicator ID-300 is the adjustment of the light rheostat and switching the range selector switch as desired. Indicator ID-586 requires no operating procedures. 45 AEROGRAPHER'S MATE 3 & 2 MAINTENANCE This equipment generally requires very little maintenance. The maintenance of this equipment consists mostly of inspection and lubrication. Transmitter Maintenance Once a week (or more often during severe weather conditions) visually inspect the trans- mitter for evidence of physical damage, such as broken impeller, rust, or weakened mast. Under normal conditions the equipment should require lubrication every 2 years. However, in a subtropic or polar climate the equipment may need lubrication more often. Normally, an AG1 or AGC accomplishes the lubrication and other maintenance which requires the dismantling of the set. If the AG3 or AG2 is on a one-man billet, or there is no AG1 or AGC, request assistance from a nearby weather unit. Indicator Maintenance The only service inspection required for the indicators, at the Aerographer's Mate 3 and 2 levels, is an observation of their operation to detect erroneous readings or failure of the lamps. Recorder Maintenance It is not recommended that any parts be repaired or replaced in the recorder other than lamp bulbs, pens, ink tanks, chart drive motors, and chart drive switches. Replacement of other recorder parts requires the use of overhaul facilities. When cleaning the recorder, DO NOT clean electrical parts. Clean the mechanical parts as follows: Wash exterior painted surfaces and the window with soap and water; rinse and dry thoroughly. Do not wash the inside of the case. Do not clean the windows with a solvent since minute cracks may result. Clean the ink tanks by prying off the covers, removing them from the recorder, and washing the parts in warm water. Rinse and dry thor- oughly. If washing does not remove all of the dried ink, loosen the remainder by soaking the tank in alcohol; then wash as before. Be sure the vent holes in the cover are open and that the cover is not bent in removing. Clean the pen element by blowing water or alcohol through it with the pen filler. Loosen clogged ink particles that block the pen by running a fine piano wire through the tube and then cleaning as above. The recorder should be lubricated every quarter. This interval is established for operation on a 24-hour basis under moderate climatic conditions. Whenever climatic con- ditions necessitate more frequent intervals for general servicing, the lubrication interval should be shortened accordingly. Avoid overlu- brication; overlubrication is injurious to the recorder. Inspect the equipment after lu- brication. Remove all excess oil, as it tends to collect dust or gum up. Oil may be properly applied by dipping a toothpick in the oil and applying it to the surface to be lubricated. Remove excess oil with a clean, lint-free cloth. The pen elements are properly balanced when they are full of ink, and the balance adjust- ment should not be changed unless necessary. Whenever rebalancing is required, screw the two balance weights as necessary along the shaft on the rear of the pen to rebalance. The pen balance should be such that when the chart is tapped lightly with one finger, the pen bounces up and down on the chart. A pen pressure that is too heavy on the chart causes the pen to drag toward the center of the chart or noticeably reduces the speed of response of the pen. Accordingly, if maximum response speed is desired, the pen pressure must be no greater than is necessary for satisfactory inking. Handle the pen element carefully; a bent element causes incorrect readings. SHIPBOARD WIND SYSTEM TYPE B3 Type B3 Wind Indicating Equipment (fig. 3-6) is installed aboard some ships to determine wind speed and direction. Aboard aircraft carriers this system is supplemented with a wind recorder of the type used with the shore system (fig. 3-5). It, however, only records the apparent wind direction and speed, which must then be used to compute true wind direction 46 Chapter 3 — WIND EQUIPMENT WIND DIRECTION AND INTENSITY MASTER TRANSMITTER 209.118 Figure 3-6. — Type B3 Wind Indicating Equip- ment (shipboard). 209.362 Figure 3-7. — True Wind Computer CP-264/U. and speed. The several methods used to do this are discussed later in this chapter. This equipment is under the cognizance of NAVSEA and is serviced by the IC Electricians. The only responsibility the Aerographer has, in connection with this equipment, is reading the indicated data and maintaining the charts and ink wells on the recorder unit (See discussion earlier in chapter on the UMQ-5( ) recorder). If errors appear to exist In the readings obtained from the equipment, notify the IC Electricians. WIND COMPUTERS TRUE WIND COMPUTER CP-264/UM A plastic circular slide rule, True Wind Computer CP-264U, is issued to all ship weather offices for true wind computation (fig. 3-7). True Wind Computer CP-264U is an assembly of imprinted plastic plates used aboard ship to compute true wind speed and direction when the apparent wind speed and direction, and ship's course and speed are known. The computer is also used to determine the ship's course and speed required to produce a desired apparent wind direction and speed. The computer consists of an oval base plate and a clear plastic compass rose fastened with a center pivot. The compass rose is free to rotate and to slide along the long axis of the base plate. All computations are made directly on the computer, and solutions are read directly off its scales. Directions for use are printed on the reverse side of the base plate. (The directions on the computer use the term "relative wind", whereas this text and FMH # 1 use the term "apparent wind." Both refer to wind determined from equipment orientated on the bow of the ship.) 47 AEROGRAPHER'S MATE 3 & 2 An example of how the computer is used for the determination of true wind direction and speed is set out below: Assume that the apparent wind direction and speed are 300° and 18 knots, and the ship's course and speed are 080° and 16 knots. 1. Slide the rotor disc along the ship's speed reference line until the center index of the rotor disc is opposite the ship's speed, 16 knots, and then rotate the disc until the ship's heading, 080° true on the compass rose of the rotor disc, is directly over the 000°/360° bearing radius of the base plate. 2. Plot with a grease pencil a dot on the rotor disc at the point determined by the apparent wind direction, 300° true, and speed 18 knots, utilizing the base grid. 3. Slide the rotor disc to the zero of the ship's speed reference index (the center of the concentric circles of the base plate) and rotate the disc until the grease pencil dot, previously plotted, lies along the 000°/360° bearing radius of the base plate. The true wind direction, 328°, can now be read directly off the rotor disc over the 000°/360° bearing radius of the base plate. The true wind speed, 17.5 knots, can now be read directly opposite the grease pencil dot by utilizing the ship' s speed reference index. For the determination of a ship's course and speed required to produce the desired apparent wind direction to produce the desired wind direction and speed, assume that the apparent wind direction desired is 5° off the port bow and the apparent wind speed is 40 knots, actual apparent wind direction and speed are 300° and 18 knots, present ship's course is 080° true, and present ship's speed is 16 knots. 1. Repeat steps 1, 2, and 3 of the above example to find the true wind direction and speed of 328° and 17.5 knots. 2. Manipulate the rotor disc (by rotation and sliding along the 000°/360° bearing radius of the base plate) until the grease pencil dot, the head of the true wind vector, is directly over the reference point on the base plate as determined by the given requirements of the desired apparent wind (direction at 5° off the port bow and speed of 40 knots across the deck) , utilizing the grid of the base plate. 3. Read directly off the rotor disc the ship's course, 340° true, which is directly over the 0007360° bearing radius of the base plate. Read directly the ship's speed, 23.5 knots, opposite the center of the rotor disc, from the ship's speed reference index. This ship's course, 340° true, and a speed of 23.5 knots, with the given true wind direction and speed, will produce the desired apparent wind direction, 5° off the port bow, and a speed of 40 knots across the deck. Checking Computed Winds The following may be used to check computed wind values: 1. The true direction of the wind is always on the same side of the ship as the apparent direction, but farther from the bow (port or starboard) than the apparent direction. 2. The true speed of the wind is greater than the apparent speed whenever the apparent direction is aft of the beam. 3. The true speed of the wind is less than the apparent speed whenever the true direction is forward of the beam. TRUE WIND OBSERVING METHOD In the absence of a computer, the true wind direction may be observed by noting the direction from which small wavelets, ripples, and sea spray are coming. To accomplish this, sight along the wave crests, then turn 90 degrees to face the advancing waves; this is the true direction, which is evaluated to the nearest 10 degrees, (See table 3-1.) The true wind speed may be estimated by observing the sea condition and referring to table 3-3 or Appendix VI. However, the observer should be aware of the assumptions upon which these estimations are based, such as that the wind is well removed from land and that the wind has been blowing from a constant direction and speed long enough to cause the present sea condition. Some of the factors which will result in an underestimation of true wind speed are as follows: 1. Off-shore winds within sight of land. 2. Moderate to heavy precipitation causing a smoother than normal sea condition. 48 Chapter 3 — WIND EQUIPMENT Table 3-3.-True Wind Speed From Sea Condition Knots Sea Conditions Probable wave height in feet 0-1 1-3 4-6 7-10 11-16 17-21 22-27 28-33 34-40 41-47 48-55 56-63 64 and over Sea smooth and mirrorlike Scalelike ripples without foam crests ................... Small, short wavelets; crests have a glassy appearance and do not break Large wavelets; some crests begin to break; foam of glassy appearance. Occasional white foam crests Small waves, becoming longer; fairly frequent white foam crests Moderate waves, taking a more pronounced long form; many white foam crests; there may be some spray Large waves begin to form; white foam crests are more extensive everywhere; there may be some spray Sea heaps up, and white foam from breaking waves begins to be blown in streaks along the direction of the wind; spindrift begins Moderately high waves of greater length; edges of crests break into spindrift; foam is blown in well-marked streaks along the direction of the wind High waves; dense streaks of foam along the direction of the wind; crests of waves begin to topple, tumble, and roll over; spray may reduce visibility Very high waves with long overhanging crests. The resulting foam in great patches is blown in dense white streaks along the direction of the wind. On the whole, the surface of the sea is white in appearance. The tumbling of the sea becomes heavy and shocklike. Visibility is reduced Exceptionally high waves that may obscure small and medium -si zed ships. The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility reduced The air is filled with foam and spray. Sea completely white with driving spray; visibility very much reduced 1/4 1/2 2 4 6 10 14 18 23 29 37 45 3. Winds have just sprung up or increased in speed. Some of the factors contributing to an over- estimation of true wind speed are as follows: 1. A decreasing wind speed. 2. Waves running into shallower water. MAINTENANCE For maintenance procedures for computers refer to chapter two. NOTE: Changes to all column numbers and entries on NWSC Form 3140/8 were received too late for inclusion in this manual. Where errors in column numbers appear, refer to the U S Navy Supplement to FMH #1, Chapter 13, Marine Aviation Observations for the most recent ampli- fying instructions. 49 CHAPTER 4 TEMPERATURE, HUMIDITY, AND PRECIPITATION Many parameters are important in the field of meteorology; included among them are tem- perature, humidity, and precipitation. In this chapter the various terms associated with tem- perature, humidity, and precipitation will be defined, along with a description and use of the various types of sensing equipment, both manual and electronic, including a brief resume of the oceanographic sensors. TEMPERATURE, HUMIDITY, AND PRECIPITATION Before proceeding with a discussion of tem- perature, humidity, and precipitation, one needs to have a working knowledge of some of the terms used to define them. DEFINITIONS 1. Temperature. Temperature is defined as the measure of molecular motion or the de- gree of heat of a substance. It is measured on an arbitrary scale from absolute zero where the molecules theoretically stop moving. A longer and more comprehensive definition is given in chapter 12 of this training manual, as are descriptions of the temperature scales in use in meteorology today. Temperature, as used in surface observa- tions, refers primarily to the free air or the ambient temperature close to the surface of the earth. Other temperatures are also ob- served during the course of an observation, such as the maximum, the minimum, sea water, and others. 2. Humidity. Humidity is the state of the atmosphere with respect to water vapor con- tent. However, since there are several ways in which to express the water vapor content, it Is better to specify which type of humidity is meant. 3. Dew point. The dew point is defined as the temperature to which a sample of air must be cooled, while the mixing ratio and barometric pressure remain constant, in order to attain saturation with respect to water. The dew point can never exceed the dry- bulb temperature in any given observation. When the air is saturated, the dew point and the temperature are the same and the relative humidity is 100 percent. 4. Dry-bulb temperature. The dry-bulb tem- perature is the natural temperature of the ambient atmosphere at the point and time of observation and is synonymous with the surface temperature. 5. Wet-bulb temperature. The wet-bulb tem- perature is the lowest temperature to be se- cured in the ambient atmosphere in its natural state by evaporating water from the wick-cov- ered bulb of a thermometer at a specified rate of ventilation. It differs from the dry-bulb tem- perature in an amount dependent on the tem- perature and humidity of the air. This difference is termed the wet-bulb depression. 6. Relative humidity. Relative humidity, with respect to water, is the ratio of the actual vapor pressure in the air to the saturation vapor pressure that would exist if the sample of air were saturated at the same pressure and temperature. 7. Psychrometer. A psychrometer is an in- strument used for measuring water vapor con- tent of the atmosphere. It consists of two thermometers, one of which (the dry bulb) is an ordinary glass thermometer, while the other (the wet bulb) has its bulb covered with a jacket of clean muslin which is saturated with distilled water prior to an observation. When the bulbs are suitably ventilated, they indicate the ther- modynamic wet- and dry-bulb temperature of the atmosphere. 50 Chapter 4 — TEMPERATURE, HUMIDITY, AND PRECIPITATION 8. Precipitation. Precipitation is any and all forms of water particles, whether liquid or solid, that fall from the atmosphere and reach the ground. It is distinguished from clouds, fog, dew, etc., in that it must "fall"; and from clouds and virga, in that it must reach the ground. The amount of fall is usually ex- pressed in inches of liquid water depth of the substance that has fallen at a given point over a specified period of time. 9. Precipitation gage. A general term for any device that measures the amount of pre- cipitation. 10. Hygrothermometer. An instrumental sys- tem for obtaining dew point and ambient air temperatures from dial indicators or recorder traces and the use of remoted sensors as ther- mometers. The hygrothermometer, for the Navy, is the temperature/humidity portion of Semi- automatic Meteorological Station AN/GMQ-14. The Automatic Weather Station AN/GMQ-29 is an equivalent system. 11. Station standard system. For the Navy, the station standard system is the AN/GMQ-14 or AN/GMQ-29. (Liquid-in-glass thermometers are the station standard system for those sta- tions not equipped with an AN/GMQ-14 or AN/ GMQ-29.) 12. Station standby system. The station stand- by system, for the Navy, consists of the various liquid-in-glass thermometers or psychrometers. DETERMINING TEMPERATURE, HUMIDITY, AND PRECIPITATION Throughout the Naval Weather Service today various assortments of temperature, humidity, and precipitation devices exist; they are com- pletely automatic, semiautomatic, or manually operated. The order of precedence for use of the various sensing instruments depends on the elements being sensed. For temperature and humidity, the first order of priority is the hygrothermometer or equivalent system which is the Semiautomatic Meteorological Station AN/GMQ-14 ( ), and the temperature/dew point temperature sensing system of the Automatic Weather Station AN/GMQ-29, respectively. If these systems are not available or properly operating, the next choice will be the psychro- meters , the hand-held electric psychrometer AN/ ML-450A/UM or the manual sling and rotor psychrometers, which utilize the liquid-in-glass type of thermometers. Remoted Sensor Reading When the AN/GMQ-29( ) is used to obtain psychrometric values, the dry-bulb and dew- point temperatures are read to the nearest whole degree directly from the digital win- dows. When the AN/GMQ-14( ) is used, these values are obtained from the left-hand edge of the recorder traces. These values are then used to determine the remaining psychrometric data that is required. Psychrometers SLING AND ROTOR PSYCHROMETERS.— Procedures for exposure, moistening the wet- bulb, aspiration, and reading the thermometers are detailed in FMH-1. ELECTRIC PSYCHROMETER. — Procedures for this instrument vary from those outlined in FMH-1 for psychrometers. 1. Place the instrument on a flat surface with the graduations of the thermometer facing up- ward and the air intake positioned into the wind and to the left of the operator, or 2. Grasp the instrument in the left hand with the fingers fitting the curved portion of the case, the graduations of the thermometers facing the operator, and the air intake point- ing to the left and into the wind. CAUTION: In either position, the air in- take and both exhaust ports must be entirely free of obstructions and far enough away from the operator's body or any other source of moist air or temperature that may cause a false reading. Turn the switch knob clockwise to start aspiration. If thermometer illumination is de- sired, continue turning the knob clockwise un- til sufficient light intensity is obtained. When the wet-bulb temperature stabilizes' at a m'nlmum value, note the readings of both thermometers and turn off the switch by turn- ing the knob counterclockwise. Expose the psychrometer to the free air for at least 5 minutes before using it for read- ings. Exposure of this instrument is dependent on the outside air temperature. If it is 50° F 51 AEROGRAPHER'S MATE 3 & 2 or above, expose the psychrometer to ambient air conditions without the ventilating fan run- ning. When the outside air temperature is below 50° F, expose the psychrometer to ambient air with the ventilating fan running. Thoroughly saturate the wet-bulb wick, with pure water, taking every precaution to prevent water from contacting either the thermometer tube or the dry bulb. Any moisture which may have contacted the dry bulb must be removed. After observing the wet- and dry-bulb tem- peratures, calculate the difference between the dry-bulb and the wet-bulb temperature read- ings. After the difference or wet-bulb depres- sion is obtained, the next step is to compute the dew point and relative humidity by use of Psychrometric Computer CP-165/UM. The in- structions are printed on the computer. The psychrometric computer is used, utilizing the scale closest to the NORMAL station pressure (e.g., sea-level stations will use a 30-inch scale for all observations). If the normal sta- tion pressure is not known, refer to FMH No. 1 to determine the appropriate scale to use based on the elevation of the station. Precipitation For determining the amount of precipita- tion, most Naval Weather Service units employ the 4-inch rain gage or the tipping-bucket rain gage ML- 558, which is an integral part of the AN/GMQ-29( ) and AN/GMQ-14( ). Precipitation is measured on the basis of the vertical depth of water, or water equivalent, which would accumulate within a specified time on a level surface. The inch is the unit of measurement for precipitation. The vertical depth of water, or water equivalent, is expressed to the nearest 0.01 inch; less than 0.005 inch is called a trace. Precipitation measurements are made from samples caught in gages, or from samples taken from representative areas when the catch of solid forms in the gage is not representa- tive. Precipitation observations are taken at the time of each regular 6-hour observation and at the time of the midnight observation. The tube of the 4-inch rain gage, when full, holds 1 inch of rainfall. In the event that more than 1 inch falls between the above-mentioned observations, the excess drains into the over- flow container. At the next observation the amount collected in the measuring tube and overflow container is measured. The rain gage unit of the AN/GMQ-29( ) and AN/GMQ-14( ) records each 0.01 inch of liquid water precipitation that falls at the sta- tion. The depth measurement of the water equiva- lent of the solid forms of precipitation, such as snow, ice pellets, hail, and freezing rain, is more difficult to obtain. The rain gage can be used, provided the collector ring and meas- uring tube are removed. The solid forma are collected in the overflow 'jontainer. At the time of the observation a measured amount of warm water can be added to the contents of the con- tainer to melt the solid forms. Once melted, the measurement can be made as for rainfall. The added amount of water, of course, must be deducted in computing the total water equiva- lent. In measuring snow, another method is to obtain a definite volume of the snow from a representative area by removing the overflow container and using it like a doughnut cutter to remove a snow section. This can be melted and measured as described above. When the water equivalent of snow cannot be accurately measured by melting, the observer may use one-tenth of the average snow depth as the water equivalent; that is, 10 inches of snow correspond to 1 inch of melted snow. However, when use of a ratio method is necessary and the mean ratio for the station is known to differ from 1/10, or there is reason- able evidence that an individual situation re- quires a difference ratio, estimate the amount on the basis of available evidence. For example, it may be known that at a particular station 8 inches of snow usually correspond to 1 inch of melted snow; therefore a l/8 ratio is used. Enter the ratio used and the reasons for its use in block 90 of MF1-10. Other than determining the vertical depth of the water equivalent of the solid formr>, the observer must measure them — especially snow — in their solid state. This is accomplished by thrusting a measuring stick Into snow at sev- eral places and obtaining an average of all the 52 Chapter 4 — TEMPERATURE, HUMIDITY, AND PRECIPITATION measurements. If the ground is covered by ice beneath the snow, the observer must cut through the Ice, measure the thickness, and add it to the depth of the snow above the ice. The unmelted depth of solid forms that have fallen during the 6 hours ending with the observations is ex- pressed in inches to the nearest tenth of an inch, but the total depth of solid forms on the ground at the time of observation is ex- pressed to the nearest inch. OBSERVATIONS AND FORMS A varied assortment of forms are used to record temperature, humidity, and precipitation observations. Some have already been discussed, such as the MF1-10 and NWSC Form 3140/8. The AN/GMQ-29 records rainfall and winds while the AN/GMQ-14( ) records temperature, dew point, and rainfall on recorder rolls. These forms and record rolls and their entries are discussed in the following paragraphs. MF1-10 and NWSC Form 3140/8 Entries Entries of temperature, dew point, maximum and minimum temperature, and climatic in- formation are made in accordance with the criteria set forth in the following paragraphs. Again, when this chapter does not cover an as- pect of the problem at hand, consult FMH No. 1, Surface Observations. TEMPERATURE (COL. 7). — Temperature Is entered to the nearest whole degree Fahrenheit, prefixing a minus sign to a subzero tempera- ture. DEW POINT (COL.8). — Entered the same as temperature unless the dry-bulb tempera- ture is -35° F or below. Then assume the dew point, with respect to ice, to be the same as the dry-bulb. The water equivalent of this value Is computed and then entered in paren- theses. PRECIPITATION (COL. 44). — Measurements of all forms . of precipitation are expressed In terms of vertical depth of water accumulated within a specified time on a horizontal surface. Enter total precipitation (water equivalent) In inches and hundredths. Also, when: 1. No 6-hour precipitation occurs, enter "0". 2. A trace, but less than 0.005 inch falls, enter "T". 3. No 6-hour precipitation up to the actual observation time, but precipitation was observed prior to coding of the observation, enter "T" even though the amount may be measurable. If the water equivalent of solid precipita- tion cannot be measured by melting or weighing of the sample, enter the estimated water equiva- lent on the ba3is of the ratio method. For fur- ther details, see FMH No. 1. SNOWFALL (COL.45). — In this column, enter the maximum unmelted depth, in Inches and tenths, of solid precipitation that has fallen during the 6 hours ending with the observation. Additional entry instructions are as follows: 1. No 6-hour snowfall, enter "0". 2. A trace but less than 0.05 Inch, enter "T" and in block 90, when snowfall melted as it fell, enter also "T — Melted as it fell." 3. If several occurrences of solid precipi- tation oocur in the period, such as snow showers, and each fall melts either completely or par- tially before the next occurs, enter the total of the meximum depths accumulated by each fall. 4. As a prefix to estimated amounts, enter "E"; in block 90, enter "E — Estimated due to melting." 5. Enter an asterisk (*) as a prefix to HAIL amounts, and in block 90, enter "*HAIL," un- less other solid forms of precipitation occurred during the period. Additional information is contained In FMH No. 1. SNOW DEPTH (COL.46). — In this column, to the nearest Inch, enter In the 6-hourly spaces the depth of solid precipitation and ice on the ground at each 6-hourly observation. Additional entry instructions are contained in FMH-1. MAXIMUM TEMPERATURE (COL.47). — En- ter the maximum temperature in whole degrees Fahrenheit that has occurred in the 6 hours prior to each 6-hourly observation and between midnight and the first 6-hourly observation and between the last 6-hourly observation and mid- night, on the line captioned 1,2,3, and 4 and MID TO and MID, respectively. MINIMUM TEMPERATURE (COL.48). — En- tered the same as column 47. 53 AEROGRAPHER'S MATE 3 & 2 24-HOUR MAX AND MIN TEMPERATURES (COL. 66 & 67). — Col. 66 will be the maximum value recorded in col. 47 for the day. Col. 67 will be the minimum value recorded in col. 48 for the day. Note that the value on the line captioned "1" in cols. 47 and 48 is for a period extending prior to midnight (LST); consequently this value is disregarded in deter- mination of the 24-hour maximum and mini- mum temperatures. 24-HOUR PRECIPITATION (COL.68). — En- ter the total precipitation (water equivalent) for the 24 hours ending at midnight to the nearest 0.01 inch. 24-HOUR SNOWFALL (COL.69). — Enter the total amount (unmelted) of solid precipitation that has fallen in the 24 hours ending at mid- night LST. SNOW DEPTH (COL.70). — Enter the depth of solid precipitation and ice on the ground at 1200 GMT or, in areas other than the con- tiguous United States, a time modified as nec- essary to meet regional needs. Entries are made to the nearest whole inch. PRECIPITATION, THUNDERSTORMS, AND OBSTRUCTIONS TO VISION (COL. 82/86). — En- ter form of precipitation occurring at the sta- tion. All entries will be in accordance with the appropriate tables in FMH-1 or Table 10-1 of this manual. BEGAN' and ENDED (COL. 83 & 84). — En- ter the local standard time that the precipi- tation entered on the same line in column 82/ 86 began (COL. 83) and ended (COL. 84). When any of these phenomena is occurring at midnight, enter "Cont." in column 84 for the day ending at midnight, and in column 83 for the day beginning at midnight. NWSC FORM 3140/8 Entries SEA WATER TEMPERATURE. — Enter sea surface water temperature to the nearest tenth degree Celsius. Corrected readings from the condenser intake may be used provided such corrections have been determined by a series of comparative bucket-condenser readings for the ship's current speed. The method for taking bucket observations is explained in FMH No. 1. AN/GMQ-29( ) and AN/GMQ-14( ), Temperature, Dew-point, and Precipitation Recording Charts The AN/GMQ-29( ) recording chart records only precipitation and wind (which was dis- cussed in chapter 3), while the AN/GMQ-14( ) records temperature, dew point, and precipi- tation. The AN/GMQ-29( ) chart should be changed at midnight (LST) on the 1st of every month, and as often thereafter as necessary. The charts should be annotated in accordance with the following: 1. At the beginning and end of each chart enter the station name, date, and time to the nearest minute (LST) when the chart was put on or taken off. 2. Time-check the chart at every 6-hourly observation, with the time to the nearest minute. 3. When the chart is adjusted for time, in- dicate the adjustment on the chart by entering an arrow at the point of the adjustment and write row. the time of the adjustment near the ar- 4. Time check the chart upon notification of an Aircraft Mishap. 5. For each disruption or discontinuity, such as a power failure, equipment failure, etc., enter on the chart at this point the reason and time of the interruption. When returned to ser- vice, correct the chart for time and enter a time check. An appropriate entry should also be made in block 90 of MF1-10. 6. Enter a time-check at the first observa- tion of the day at stations not operating 24 hours per day. THERMOMETERS Thermometers are classified according to their operating principles and their purpose. In this section only the liquid-in-glass ther- mometers are discussed. Llquid-in-glass thermometers are designed on the principle of differential expansion. The fluid used In the thermometer expands and con- tracts at a different rate than the glass tube It is contained in. By etching an appropriate scale on the tube we can measure this difference in expansion and thereby determine the change in temperature. 54 Chapter 4 — TEMPERATURE, HUMIDITY, AND PRECIPITATION STANDARD The standard air thermometer which you are more than likely familiar with is the one placed inside or outside of the house to see how cold or warm the temperature was during the day or how cool the air conditioner is keeping the house. There are many common uses for this thermometer which is usually filled with either mercury or alcohol depend- ing on its intended use. These two fluids are used because they have a much greater co- efficient of expansion for each degree of change in temperature than glass has. (See figure 4-1.) The range of the standard air thermometer used by the Naval Weather Service is from -20° F to +120° F. Handle these thermometers carefully; they break easily. It is important that the thermom- eter stem and bulb be kept clean and free of dirt, dust, and salt spray since the presence of dirt or moisture on the bulb causes an errone- ous indication of the free air temperature. Clean the stem and bulb by wiping with a soft cloth. This should be done 10 to 15 minutes prior to taking a reading so the temperature will have time to stabilize before the observa- tion. Remove and clean the metal back as nec- essary. Upon reassembly apply a drop of light oil to the brass mounting screws. Renew the etched graduations when faded. To reunite a separated mercury column, at- tach a psychrometer sling to the thermometer metal back and whirl it, or tap the bulb lightly against the heel of the fleshy part of the hand so as to jar the mercury column back together. If this fails, gently heat the bulb by placing it near a light bulb until the column unites. Never heat the bulb over an open flame. Leave a small space at the top of the tube while heating; otherwise the thermometer will break. If these methods fail to unite the mercury column, then replace the thermometer. Some isolated stations may still utilize the maximum and minimum thermometers. These are shown in figure 4-2. Procedures for their use and operation are found in the Federal Meteorological Handbook No. 1. SHELTERS With the increased use of automatic weather stations, such as the AN/GMQ-29( ) that have self-contained shelters for their sensing ele- ments, the wooden-type shelters are becom'ng a thing of the past. However, some stations still using the AN/GMQ-14( ) and isolated overseas stations may have the wooden-type shelters still installed. (See figures 4-3 and 4-4.) These instrument shelters are used to house several meteorological instruments including the psychrometer and the maximum and minimum thermometers. PSYCHROMETERS The several types of psychrometers have as their basic construction two thermometers secured as a unit to a metal back or support- ing device. They may be hand-held (sling-type and electric) or rotor-mounted instruments. The primary objective is to obtain the tem- perature readings of the dry-bulb and the wet- bulb thermometers, and then calculate the difference between the two readings. The difference is called the depression of the wet bulb, which is used to find relative humidity, dew point, and vapor pressure. Observations are interpreted by consulting appropriate psy- chrometric tables or computers. 209.85 Figure 4-1. — Standard air thermometer. 55 AEROGRAPHER'S MATE 3 & 2 TOWNSEND SUPPORT CONSTRICTION (A) LOWER CAREFULLY TO VERTICAL POSITION TO READ INVERT FOR SETTING MIN. TEMP. HERE CURRENT TEMP. CURRENT & MIN. TEMPERATURE (B) INDEX Figure 4-2. — (A) Maximum thermometer (B) Minimum thermometer. 209.86:.87 56 Chapter 4 -TEMPERATURE, HUMIDITY, AND PRECIPITATION CA* 209.83 Figure 4-3. — Standard instrument shelter. (A) Construction of support. (B) Instrument arrange- ment inside the shelter. SLING The sling psychrometer, is shown in figure 4-5. The sling consists of a wooden grip with a swivel head and harness-type snap or spring clip for attaching to the top hole of the psy- chrometer frame. When not in use, the sling psychrometer should be hung on a suitable hook. Handle the sling psychrometer carefully at all times. The thermometers are easily broken through careless handling, dropping, or strik- ing some object while being whirled. For a check on humidity, take it to a clear and open place, preferably exposed to the wind. Never touch the bulb or stem in handling or expose It to the direct rays of the sun while making an observation. The bulb of the wet- bulb thermometer, which is covered with a 209.392 Figure 4-4. — Shelter used with AN/GM3-14( ). wick, is moistened with clean water at the time an observation is made. Stand in a clear shady place facing into the wind, and hold the psy- chrometer as far in front of the body as pos- sible. Rotate the psychrometer with the wrist. Bring the psychrometer to a stop without any sharp jar and bring to eye level. Then read both thermometers to the nearest tenth of a degree, reading the WET-BULB thermometer FIRST. The whirling is repeated, and other readings are made until two successive wet- bulb readings are the same. Amplifying in- formation is contained in FMH-1. ROTOR The rotor psychrometer illustrated in fig- ure 4-6 is a psychrometer element secured 57 AEROGRAPHER'S MATE 3 & 2 SWIVEL SNAP LINK (B) Figure 4-5. — (A) Standard psychrometer; (B) with sling attached. 209.88: .89 to a handcrank-operated shaft. The rotor is designed for wall mounting and permits a per- manent installation in the right side wall of the instrument shelter. The same procedure is followed in obtaining a correct reading of the rotor-mounted psychrometer as was given for the sling psychrometer except that the instru- ment is left in the instrument shelter. ELECTRIC ML450A/UM Hand Electric Psychrometer ML-450A/UM is a portable instrument used to obtain free air temperature and the wet-bulb temoerature. (See fig. 4-7.) Although the psychrometer is constructed primarily of noncorrodible materials, prolonged exposure to weathering, salt air, stack gases, and other corrosive elements shorten the use- ful life of the instrument. The instrument should therefore be sheltered when not in actual use. The two thermometers comprising the psy- chrometer have a range from plus 10° F to plus 110° F. The psychrometer comes with a carrying case and three water bottles. With the exception of the three standard flashlight batteries which supply the power, it is ready for operation as issued. (See fig. 4-8.) Maintenance Hand Electric Psychrometer ML-450A/UM requires very little maintenance. For proper operation, the instrument should be kept free of dirt and other foreign matter. When the instrument is not to be used for a prolonged period of time, remove the batteries from the case because batteries will corrode and damage the instrument. When cleaning the instrument, wash all plas- tic parts with a mild soap and warm water; rinse with clear water and dry. Wash the ther- mometers with a mild soap and warm water; rinse with clear water and dry. Wipe electrical contacts with a clean lint-free cloth. If nec- essary, fine sandpaper may be used to remove 58 Chapter 4 — TEMPERATURE, HUMIDITY, AND PRECIPITATION 1. Sliding door. 2. Spring contact. 3. Battery com- partment. 4. Water bottle. 5. Bottle com- partment. 6. Hinge pin. 7. Thermometer holder. Wet -bulb wick. 9. Knob. 10. Exhaust ports. 11. Sliding air intake. Figure 4-6. — Rotor psychrometer. 209.90 209.116 Figure 4-7. — Hand electric psychrometer ML- 450A/UM. corrosion or pitting. No lubrication is necessary for this instrument; no special tools are re- quired for its overhaul. BATTERIES. — Three size D (standard flash- light) dry cell batteries are required. To insert the batteries, remove the sliding door at the end of the case and rotate the spring contact from the battery compartment to the bottle compartment. The batteries must be inserted so that the center contact enters the compartment first. After the batteries are in place, rotate the spring contact to its original position on the end battery and replace the sliding door. REPLACING THE WICK. — To replace the wick, first remove the sliding air intake ex- posing the thermometer bulbs. Then remove the wick. Slip a length of wicking over the bulb. Secure at the top of the bulb with a thread at the constriction between the bulb and the stem, using a loop and square knot. Form a loop in a second thread and place it at about the middle of the bulb, stretching the wick firmly and snugly against the bulb. Tie with a double loop and square knot at the end of the bulb. Clip the ends of the thread and cut off the excess wicking about one-eighth inch below the bottom of the bulb. REMOVING AND REPLACING THERMOM- ETERS. — If either thermometer is damaged, it is necessary to remove both thermometers and replace them with a matched pair. To remove and replace the thermometers, first remove the air intake and the thermometer 59 AEROGRAPHER'S MATE 3 & 2 1. Neck strap. 2. Spare thermometers. 3. Psychrometer. 4. Instructions and tables. 5. Box (extra wick, thread, and lamp). 6. Two-ounce bottle. 7. Carrying case. 209.117 Figure 4-8. — Hand electric psychrometer in carrying case. retainers. Then lift out the thermometers. Re- move the rubber bushings from the bulb ends of the thermometers and the bushings from the other ends of the thermometers. Place the longer bushings on the bulb end of the new thermometers so they are flush with the end of the thermometer holder. This seals the small holes in the air intake when it is slid into position. CAUTION: Position the rubber bushings on the thermometer so the retaining clamps rest on them. Otherwise, the pressure of the re- taining clamps may break the thermometers. Replace the thermometers, positioning them so the graduations are visible and both mer- cury columns are magnified when viewed from the same position. Replace and tighten the ther- mometer retaining clamps. 60 Chapter 4 -TEMPERATURE, HUMIDITY, AND PRECIPITATION REUNITING MERCURY COLUMN. — If the mercury column of either thermometer sep- arates, an effort should be made to reunite the mercury column. To do this, remove the thermometer as described earlier. Gently heat the thermometer bulb under a light bulb to gradually force the mercury to the top of the tube. Care must be taken so the mercury does not cause the thermometer to burst. Upon cooling, the mercury should recede as a united column. REPLACING THE LAMP. — To replace a lamp, first remove the sliding air intake and retaining screw that keeps the thermometer holder in the correct position. Then raise the unrestrained end of the thermometer holder upward to provide access to the lamp. Finally, remove the red filter and change lamps, re- place the filter, and secure the thermomster holder; replace the air intake. INSPECTIONS. — Inspect for cracks or breaks in the plastic parts. Inspect threaded holes and screws for wear, and the fan for damage. In- spect the thermometers for cracks and sepa- rated mercury columns. Inspect the carrying case for damage, and the motor shaft for smoothness of rotation. REPAIR OR REPLACEMENT. — All plastic parts that are broken, cracked, or have missing or damaged threaded inserts should be replaced. Damaged screws should be replaced. If the motor shaft does not turn freely or if the fan is damaged, the motor and fan assembly should be replaced. If the contacts on the contact block do not contact the motor terminals cor- rectly, they should be carefully bent so that good electrical contact is ensured. A carrying case that is damaged beyond use should be replaced. SEMIAUTOMATIC AND AUTOMATIC WEATHER STATIONS The AN/GMQ-29( ) is scheduled to com- pletely replace the AN/GMQ-14( ). Because of the lengthy installation period, both the AN/ GMQ-14( ) and the AN/GMQ-29( ) are discussed in this manual. AN/GMQ-14( ) Semiautomatic Meteorological Station AN/ GMQ-14( ) is an electromechanical instrument system with facilities to house, sense, and re- cord temperature, dew point, precipitation, pres- sure, and wind. (See fig. 4-9.) Barometer ML-448/UM and the Marine Barograph are covered in chapter 2 of this training manual. Wind Recorder RD-108( )/UMQ-5 is covered in chapter 3, along with the AN/UMQ-5( ) wind system. This station includes a rain gage; a DEWCEL (dew point sensing element) housed in a shelter; a dewcel power supply; a dew point transmitter; an air temperature bulb; and air temperature transmitter; an equipment rack containing a combined rainfall, dew point, and temperature recorder; a 24-hour clock; a junction box; and a test cord. Three systems in the semiautomatic mete- orological station are covered in this chapter. They are the dew-point measuring and record- ing system, the air temperature measuring and recording system, and the rainfall gaging and recording system discussed under rain gages. Dew-point Measuring and Recording System The dewcel, covered with woven glass tape impregnated with lithium chloride and wrapped with gold or silver wires, measures the dew- point temperature. The current for the dewcel passes through the dewcel power supply, consisting of a step- down transformer and an incandescent lamp used as a ballast resistor. The dewcel actuates the temperature element in the transmitter as- sembly. Air Temperature Measuring and Recording System The temperature measuring and recording system operates similarly to the dew-point measuring and recording system. Instead of the dewcel, a temperature bulb is used and no separate power supply is required. The temperature bulb is similar to the dewcel minus the glass tape and wire wrappings. The sig- nal is recorded by the center pen on the right half of the chart. 61 AEROGRAPHER'S MATE 3 & 2 209.114 Figure 4-9. — Semiautomatic meteorological station AN/GMQ-14( ). 62 Chapter 4 — TEMPERATURE, HUMIDITY, AND PRECIPITATION Recorder and Case Assembly The recorder and case assembly is a con- venient means of combining in a single as- sembly the receivers, recorders, and power controls for the three systems. A synchro- nous motor drives the chart. One ink reservoir supplies the air temperature and dew-point re- cording pens. The rainfall recording pen has an independent ink reservoir. The power input for all three systems as well as for the re- corder is in the recorder case assembly and is designed for 11 5- volt, 60-cycle, ac. The power switch for the three systems, the re- corder lights switch, and the chart drive speed switch are also in the recorder case. Operation As its name indicates, the semiautomatic meteorological station requires a minimum of operating procedures. The main switch, gov- erning the recorder and the three systems, is at the front of the recorder case at the left side. Placing it ON provides current for the recorder, the transmitters, the rain gage, and the dewcei power supply. The transmitters op- erate automatically as soon as current is sup- plied to them. The only operation required for the rain gage is emptying the measuring cylinder. FILLING INK RESERVOIRS AND PENS.— Ensure that the main power switch is turned OFF. Lift the pens from the chart by using the pen lifter; then remove the pens by lifting them straight up and out of their carriage slots. Lift the reservoirs out of the recesses in which they are located. Be careful not to spill any of the remaining ink on the recorder, as removal of the ink is difficult. Fill the reservoirs about three-fourths full of ink. Care- fully replace the reservoirs in the recorder. Place the pens in the slots in their respective carriages. Using a common soda straw, fold the end over and pierce a small hole with a pin about one-fourth inch from the folded end. Insert the pen tip in this hole and suck on the open end of the straw until ink is drawn through the pen tube into the straw. The trans- lucent material of the straw allows the op- erator to see when ink is entering from the pen. Remove the straw. Maintenance Inspect all wiring periodically to ensure that electrical lines are intact. Set up inspection periods commensurate with existing climatic conditions. Visually inspect all housings or casings for corrosion or deterioration. Refer all other maintenance problems to your super- visor. Maintenance beyond operator maintenance is not the responsibility of the Aerographer's Mate. RECORDER. — Replace the light bulb as re- quired. Visually inspect pens to see that they are not bent or distorted. If distortion can be corrected by straightening the pen manually, bend it into shape. If the distortion cannot be corrected by straightening the pen manually, remove and replace the pen. Never allow the pens to dry out with ink in the bore. Clean the pens and reservoirs periodically, deter- mining the periods on the basis of existing cli- matic conditions. A piece of music wire is furnished for cleaning the bore of the pen tips if they become clogged. CLEANING THE PENS AND RESERVOIRS.— Chart lint should be wiped from the pen tips if a fuzzy or broad line indicates that lint is present. If the system is to be shut down or unused for extended periods of time, empty the reservoirs and wash them with clear water. Ink can be cleaned out of the pens by holding them so that a moderately strong faucet stream is directed to the reservoir end of the pen tube. If the force of the water is insufficient to flush out the pens, use an ordinary ear sy- ringe filled with water inserted at the reservoir end of the pen tube. Blow the water out of the pens after they are flushed. PERIODIC INSPECTION OF RECORDER.— Inspect the record chart daily for a clear legible record trace, proper time setting, suf- ficient chart reserve, takeup without binding, and agreement of recorded values with the indicator readings. Inspect the pens daily for evidence of clogged ink, fuzzy line on the record, and recording on sudden swings. Inspect the ink tanks weekly to see that sufficient ink is in the tanks. 63 AEROGRAPHER'S MATE 3 & 2 AN/GMQ-29( ) The AN/GMQ-29( ) Automatic Weather Sta- tion, figure 4-10, accumulates and displays meteorological data for support of air station operations and for use in forecasting. It is intended for installation at air stations where sensing equipment can measure weather con- ditions at or near the runway area and transmit the data gathered over a single audio channel to the operations area for display. The station consists of two major compon- ents. The first is the sensor group with meteorological sensors and data transmission electronics. The second is the Converter Dis- play Group, with data reception electronics, digital displays, and chart recorder. (See fig- ure 4-11.) Description of Components The sensor group consists of the signal conditioner, transmitter, and the meteorological sensors. The conditioner, transmitter, and barometric pressure sensor ML-642/GMQ-29( ) are housed in a weatherproof cabinet upon which some components are mounted. The other sensors are located as follows. AIR TEMPERATURE SENSOR (ML-641/ GMQ-29( )). — This sensor consists of a re- sistance element probe mounted in an enclosure which provides solar radiation shielding and protection from precipitation while permitting a free flow of air. (See figure 4-12.) The air temperature sensor is normally mounted with- in 15 feet of the transmitter. DEW-POINT SENSOR (ML-643/GMQ-29( )).— The dew-point sensor is a heated resistance probe installed in a chamber which permits adequate self aspiration while protecting the sensor from solar radiation, wind, and rain. (See figure 4-13.) Normal installation of the dew-point sensor is within 15 feef of the trans- mitter. RAINFALL SENSOR (ML-558/GMQ-14( )).— This system is discussed later in the chapter under rain gages. 209.393 Figure 4-10.— AN/GMQ-29( ) Automatic weather station. 64 Chapter 4— TEMPERATURE, HUMIDITY, AND PRECIPITATION Figure 4-11. — AN/GMQ-29( group. 209.394 ) Converter display ^B |§p? im • * np^^ 209.395 Figure 4-12. — Air temperature sensor ML-641/ GMQ-29( ). 209.396 Figure 4-13. — Dew point sensor ML-643/GMQ- 29( ). DATA RECEIVER AND CONTROL ASSEM- BLY. — This unit is contained in a slide-mounted drawer which provides access to all parts of the assembly from the front of the display unit. Contained within the drawer are the dis- play station power supply, electronic equip- ment for data reception and computations, and the control panel. (See figure 4-14.) Data elec- tronic equipment is contained in a circuit card cage. Also included are a time-of-day clock module and an internal digital voltmeter. The control panel, mounted just inside the drawer, has provision for control of power, selection of system calibration, setting of the time clock, resetting stored maximum and minimum tem- peratures and rainfall, and digital input and control. READOUT PANEL. — The readout panel con- tains digital displays for time of day, tempera- ture, dew point, maximum and minimum temperatures, wind speed (averaged), wind di- rection (averaged), and the digital voltmeter. (See figure 4-15.) Each display consists of sufficient digital readout lamps to display the data. 65 AEROGRAPHER'S MATE 3 & 2 T- 209.397 Figure 4-14. — Data receiver and control as- sembly. ANALOG RECORDER (RO-447/GMQ-29( )).— Mounted directly below the Data Receiver and Control Assembly, it is used to record wind direction and spsed (discussed in chapter 3 of this manual; see figure 3-4) and precipi- tation to be discussed later in this chapter under rain gages. INTERCOMMUNICATIONS GROUP (OA-8785/ GMQ-29( )). — At selected installations the AN/ GMQ-29( ) is equipped with a voice channel, which provides for use of the existing trans- mission lines for the additional purpose of full duplex voice communications between re- mote and local stations. Theory of Operation Functional operation of the Automatic Weather Station AN/GMQ-29( ) is dependent upon the fol- lowing principles. Individual sensor outputs are converted by their associated signal condition- ers to voltage levels. Timing and control cir- cuits then control data transmission over a single telephone line to the data receiver. Rain- fall information, is accepted by the formatting circuitry directly from its signal conditioner. At the display unit, the data is received, its validity verified and then routed to appropriate internal destinations for computations, record- ing, and display. For a more detailed description of the AN/ GMQ-29( ) Automatic Weather Station, refer to NAVAIR 50-30GMQ-29-1, Handbook, Opera- tion, Service and Overhaul Instruction. DIGITAL VOITMSUR WIND DIRECIION • a