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JO 7900.5D, Surface Weather Observing

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U.S. DEPARTMENT OF TRANSPORTATION ORDER FEDERAL AVIATION ADMINISTRATION JO 7900.5D Air Traffic Organization Policy Effective Date: 12/20/2016 SUBJ: Surface Weather Observing The Federal Aviation Administration (FAA) Surface Weather Observer Program is a component of the National Airspace System (NAS). It combines with other elements of the NAS to ensure the overall safety of air transportation services. The FAA is committed to providing the resources necessary to ensure the vibrancy of this critical aviation service. This order provides the practices and procedures for weather observation services that support the important role it plays in the mission of the FAA. The practices and procedures set forth in this order apply to all FAA personnel, FAA-contract personnel, and non-Federal Observer personnel who provide aviation weather observation services. Weather observer personnel are required to apply the provision of this order as it pertains to their observational responsibilities. Observers are expected to exercise experienced judgment when encountering situations not covered by this order. Distribution: Electronic Initiated By: AJT-2 12/20/2016 JO 7900.5D Table of Contents Chapter 1. Introduction ..............................................................................................................1 1.1. Purpose of This Order ......................................................................................................1 1.2. Audience ..........................................................................................................................1 1.3. Where to Find This Order. ...............................................................................................1 1.4. Cancellation .....................................................................................................................1 1.5. Explanation of Changes. ..................................................................................................1 1.6. Abbreviations and Acronyms ..........................................................................................1 1.7. Relationship to FMH-1 and Other Documents ................................................................1 1.8. Applicability of Procedures and Practices .......................................................................2 1.9. User Responsibilities .......................................................................................................3 1.10. Distribution ......................................................................................................................3 1.11. Changing the Order. .........................................................................................................3 1.12. Maintaining the Order ......................................................................................................3 Chapter 2. Guidelines ................................................................................................................4 2.1. Introduction ......................................................................................................................4 2.2. Types of Stations..............................................................................................................4 2.3. General Types of Observations ........................................................................................5 2.4. Augmentation Requirements. ..........................................................................................5 2.5. Backup Requirements ......................................................................................................6 2.6. Long-line Backup Requirements. ..................................................................................11 2.7. Certification of Personnel and Currency Requirements. ...............................................12 2.8. Types and Content of METAR/SPECI Observations ....................................................12 Chapter 3. General Procedures ................................................................................................14 3.1. Introduction. ...................................................................................................................14 3.2. Definitions......................................................................................................................14 3.3. Aviation Weather Observing Locations .........................................................................16 3.4. General Observing Practices. .........................................................................................17 3.5. Dissemination ................................................................................................................18 3.6. Corrections to Transmitted Data ....................................................................................18 3.7. Delayed Reports .............................................................................................................18 3.8. Rounding Off Numbers..................................................................................................19 3.9. Record Keeping and Forms ...........................................................................................19 3.10. Evaluating Weather Sensor Accuracy ...........................................................................19 3.11. Criteria for SPECI Observations ....................................................................................19 3.12. Content of METAR/SPECI Observations. ....................................................................21 Chapter 4. General Procedures at Automated Weather Stations .............................................32 4.1. Purpose. ..........................................................................................................................32 4.2. Types of Automated Stations .........................................................................................32 4.3. Certification ...................................................................................................................34 4.4. General Procedures ........................................................................................................34 4.5. General Equipment Procedures......................................................................................34 4.6. Procedures at Non-Federal Observation Sites. See Appendix B. .................................35 4.7. Procedures at Non-Federal AWOS Sites .......................................................................35 ii 12/20/2016 JO 7900.5D 4.8. Procedures for Handling Aircraft Mishaps at Automated Sites.....................................35 4.9. General Requirements for Record Keeping ...................................................................35 Chapter 5. Augmentation Requirements at Automated Weather Stations ..............................36 5.1. Introduction ....................................................................................................................36 5.2. Validity of Data..............................................................................................................36 5.3. Sign On/Sign Off the Automated Weather Observing Systems ....................................36 5.4. Table 5-1: Summary of FAA Augmentation Requirements ..........................................37 5.5. Order for Reporting Weather and Obstructions to Visibility.........................................37 5.6. Augmentation Observing Procedures ............................................................................38 5.7. Reporting Procedures .....................................................................................................38 5.8. Examples of Augmented Observations ..........................................................................40 Chapter 6. Backup Requirements at Automated Weather Stations .........................................42 6.1. Introduction ....................................................................................................................42 6.2. Summary of Backup Requirements ...............................................................................43 6.3. Validity of Data..............................................................................................................43 6.4. Equipment Requirements ...............................................................................................43 6.5. Procedures for Providing Backup Information ..............................................................45 6.6. Coding of Missing Data .................................................................................................45 6.7. Procedures for Wind Speed and Wind Direction ...........................................................45 6.8. Procedures for Visibility ................................................................................................46 6.9. Procedures for Present Weather and Obscurations ........................................................48 6.10. Procedures for Sky Condition ........................................................................................49 6.11. Procedures for Temperature and Dew Point. .................................................................52 6.12. Procedures for Altimeter Setting ...................................................................................53 6.13. Procedures for Documentation ......................................................................................53
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