The Safety of Experimental Amateur-Built Aircraft

NTSB Number: AAR-12-01
NTIS Number: PB2012-917001
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Executive Summary

Experimental amateur-built (E-AB) aircraft represent nearly 10 percent of the U.S. general aviation fleet, but these aircraft accounted for approximately 15 percent of the total-and 21 percent of the fatal-U.S. general aviation (GA) accidents in 2011. Experimental amateur-built aircraft represent a growing segment of the United States' general aviation fleet-a segment that now numbers nearly 33,000 aircraft.

The National Transportation Safety Board (NTSB) undertook this study because of the popularity of E-AB aircraft, concerns over their safety record, and the absence of a contemporary and definitive analysis of E-AB aircraft safety. The study employed several different methods and data collection procedures to carefully examine this segment of U.S. civil aviation. This comprehensive approach resulted in a detailed characterization of the current E-AB aircraft fleet, pilot population, and associated accidents.

Four sources of data formed the basis of this study. First, the NTSB performed a retrospective analysis of accident and activity data over the last decade to compare the accident experience of E-AB aircraft with that of similar non-E-AB aircraft used in similar GA flight operations. Second, the NTSB conducted in-depth investigations of all E-AB aircraft accidents during 2011, which provided a case-series of accidents for more detailed analysis. Third, a broad survey of the community of aircraft owners and builders was conducted by the Experimental Aircraft Association (EAA) in July and August 2011, and the data were made available to the NTSB for analysis to understand the population of E-AB aircraft builders and owners. Finally, discussions with EAA representatives, Federal Aviation Administration (FAA) officials, E-AB aircraft builders and owners, kit manufacturers, and representatives of E-AB aircraft type clubs provided insights on E-AB aircraft safety issues and solutions.

Recommended Safety Actions

In response to the findings of this study, the National Transportation Safety Board issued 12 recommendations to the Federal Aviation Administration and 4 recommendations to the Experimental Aircraft Association. The recommendations include expanding the documentation requirements for initial aircraft airworthiness certification, verifying the completion of Phase I flight testing, improving pilots' access to transition training and supporting efforts to facilitate that training, encouraging the use of recorded data during flight testing, ensuring that buyers of used E-AB aircraft receive necessary performance documentation, and improving aircraft identification in registry records.

Recommendations

As a result of its safety study, the National Transportation Safety Board makes the following recommendations:

To the Federal Aviation Administration:

Revise 14 Code of Federal Regulations 21.193, Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to define aircraft fuel system functional test procedures and require applicants for an airworthiness certificate for a powered experimental, operating amateur-built aircraft to conduct that test and submit a report of the results for Federal Aviation Administration acceptance. (A-12-28)

Revise 14 Code of Federal Regulations 21.193, Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to require applicants for an airworthiness certificate for experimental, operating amateur-built aircraft to submit for Federal Aviation Administration acceptance a flight test plan that will (1) ensure the aircraft has been adequately tested and has been determined to be safe to fly within the aircraft's flight envelope and (2) produce flight test data to develop an accurate and complete aircraft flight manual and to establish emergency procedures and make a copy of this flight test plan part of the aircraft's certification file. (A-12-29)

Identify and apply incentives to encourage owners, builders, and pilots of experimental amateur-built aircraft to complete flight test training, such as that available in the Experimental Aircraft Association's Test Flying and Developing Pilot Operating Handbook, prior to conducting flight tests of experimental amateur-built aircraft. (A-12-30)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to clarify those circumstances in which a second qualified pilot could be authorized to assist in the performance of flight tests when specified in the flight test plan and Phase I operating limitations. (A-12-31)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to require the review and acceptance of the completed test plan documents and aircraft flight manual (or its equivalent) that documents the aircraft's performance data and operating envelope, and that establishes emergency procedures, prior to the issuance of Phase II operating limitations.(A-12-32)

Revise Federal Aviation Administration Advisory Circular 90-89A, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, to include guidance for the use of recorded flight data for the purposes of flight testing and maintaining continued airworthiness of experimental aircraft. (A-12-33)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to include provisions for the use of electronic data recordings from electronic flight displays, engine instruments, or other recording devices in support of Phase I flight testing of experimental amateur-built aircraft to document the aircraft performance data and operating envelope and develop an accurate and complete aircraft flight manual. (A-12-34)

Develop and publish an advisory circular, or similar guidance, for the issuance of a Letter of Deviation Authority to conduct flight instruction in an experimental aircraft, to include sample documentation and sample training materials.(A-12-35)

Complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed. (A-12-36)

Revise 14 Code of Federal Regulations 47.31 and related guidance or regulations, as necessary, to require the review and acceptance of aircraft operating limitations and supporting documentation as a condition of registration or re-registration of an experimental amateur-built aircraft. (A-12-37)

Revise Federal Aviation Administration Order 8130.2G, and related guidance or regulations, as necessary, to include provisions for modifying the operating limitations of aircraft previously certificated as experimental, operating amateur-built, such as returning the aircraft to Phase I flight testing, as necessary, to address identified safety concerns or to correct deficiencies in the aircraft flight manual or equivalent documents. (A-12-38)

Revise the Civil Aircraft Registry database to include a means of identifying aircraft manufacturer, make, model, and series-such as the aircraft make, model, and series classification developed by the CAST/ICAO Common Taxonomy Team-that unambiguously identifies the aircraft kit or plans design as well as the builder of the aircraft. (A-12-39)

To the Experimental Aircraft Association:

Identify and apply incentives to encourage owners, builders, and pilots of experimental amateur-built aircraft to complete flight test training, such as that available in the Experimental Aircraft Association's Test Flying and Developing Pilot Operating Handbook, prior to conducting flight tests of experimental amateur-built aircraft. (A-12-40)

Work with your membership, aircraft kit manufacturers, and avionics manufacturers to develop standards for the recording of data in electronic flight displays, engine instruments, or other recording devices to be used in support of flight tests or continued airworthiness of experimental amateur-built aircraft.(A-12-41)

Create and publish a repository of voluntarily provided information regarding holders of Letters of Deviation Authority to conduct flight instruction in experimental aircraft. (A-12-42)

Complete planned action to create a coalition of kit manufacturers, type clubs, and pilot and owner groups and (1) develop transition training resources and (2) identify and apply incentives to encourage both builders of experimental amateur-built aircraft and purchasers of used experimental amateur-built aircraft to complete the training that is developed. (A-12-43)