Aircraft Maintenance Technology

JAN-FEB 2017

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www.AviationPros.com 41 Contained within the memorandum is a note about 14 CFR 91.403 (d), which states: "A person must not alter an aircraft based on a supplemental type certificate unless the owner or operator of the air- craft is the holder of the supplemental type certificate, or has written permission from the holder." As a result, in order to take advantage of the FAA headquarters authority for a follow-on field approval for ADS-B Out installations, the installer must be authorized by the STC holder to use the installation data. WHAT ARE THE TECHNICIAN'S PERFORMANCE RULES? The regulation (14 CFR 43.13 (a)) requires that each person performing an alteration to "use the methods, techniques, and prac- tices prescribed in the current manufac- turer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, tech- niques, and practices acceptable to the administrator." Since there is no "accept- able" data available for ADS-B Out instal- lations and since the FAA requires ADS-B Out installations to be treated as if they are major alterations, the installer must use approved data. The regulations continue with a require- ment to "use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the administrator." Every installation manual requires special test equipment to verify the proper configu- ration of the ADS-B Out system before return to service. Currently there are some 20,000 systems installed with a wholly unacceptable error rate of nearly 20 percent. What are the common installation issues? The seven most common errors are mostly in the configuration of the instal- lations. They include errors in: • Emitter Category • Air/Ground Determination Issues • Baro/Geo Altitude Spikes • Missing Baro Altitude • Duplicate or Wrong ICAOs • Invalid/Missing Mode 3/A Codes • Flight ID issues To resolve these installation errors, anyone installing ADS-B Out must familiarize themselves with AC 20-165B Airworthiness Approval of Automatic Dependent Surveillance-Broadcast Out Systems. Many people get confused because the stated purpose of the AC is to "provide guidance for the initial installation and airworthiness approval of Automatic Dependent Surveillance- Broadcast (ADS-B) Out equipment in aircraft." Since most installations are follow-on installation of some type, they dismiss the AC as not applicable. AC 20-165B Chapter 3 contains ADS-B Out system installation guidance, while paragraph 3.2.3 provides guidance on specific configuration of the associated parameters. The final issue surrounding ADS-B Out system installations is that TSO- C166b systems are also a Mode S tran- sponder, which will require retesting of the transponder under § 91.413. § 91.413 (b) states that "Following any installation or maintenance on an ATC transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E, of part 43 of this chapter." So going back to the leading question: Can an A&P; mechanic install radios? Yes, but the other regulations in Part 43, 65, and 91 require attention. ADS-B Out is not simply a radio with a couple of wires, it is an integrated system that requires installa- tion, integration, and configuration. EMITTER CATEGORY DESCRIPTION No Emitter Category Do not use this emitter category. If no emitter category fits your installation, seek guidance from the FAA as appropriate Light Airplane <15,500 lbs. Any airplane with a maximum takeoff weight less than 15,500 lbs. This includes very light aircra (light-sport aircra) that do not meet the requirements of 14 CFR 103.1. Small Airplane ≥15,500 to <75,000 lbs. Any airplane with a maximum takeoff weight greater than or equal to 15,000 lbs. but less than 75,000 lbs. Large Airplane ≥75,000 to <300,000 lbs. Any airplane with a maximum takeoff weight greater than or equal to 75,000 lbs. but less than 300,000 lbs. that does not qualify for the high vortex category. Large Airplane with High Vortex Any airplane with a maximum takeoff weight greater than or equal to 75,000 lbs. but less than 300,000 lbs. that has been determined to generate a high wake vortex. Currently, the Boeing 757 is the only example. Heavy ≥300,000 lbs. Any airplane with a maximum takeoff weight equal to or above 300,000 lbs. High Performance >5 G and >400 TAS Any airplane, regardless of weight, that can maneuver in excess of 5 G's and maintain true airspeed above 400 knots. Rotorcra Any rotorcra, regardless of weight ADS-B EMITTER CATEGORY TABLE RIC PERI is AEA vice president of government and industry affairs. Peri is an A&P; with more than 40 years of aircraft maintenance experience. He can be reached at ricp@aea.net or (202) 589-1144. AIRCRAFT ELECTRONICS ASSOCIATION

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