NTSB · Safety Recommendation
Safety Recommendation A-12-035
Recommendation
TO THE FEDERAL AVIATION ADMINISTRATION: 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.
Safety Issue and Context
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.
Response History
January 9, 2026 · Recipient Response · FAA
-From Bryan Bedofrd, Administrator: The Federal Aviation Administration (FAA) published the Final Rule, Public Aircraft Logging of Flight Time, Training in Certain Aircraft Holding Special Airworthiness Certificates, and Flight Instructor Privileges (89 FR 80310), which became effective on December 2, 2024.
The final rule (89 FR 80310) is available at the following website:
https://www.federalregister.gov/documents/2024/10/02/2024-22009/public-aircraft-logging-of-flight-time-training-in-certain-aircraft-holding-special-airworthiness
On December 13, 2024, we subsequently published Advisory Circular (AC) 91-94, Application and Issuance Process for a Letter of Deviation Authority Issued in Accordance With 14 CFR § 91.326. The AC provides information and guidance on the application and issuance process for obtaining a letter of deviation authority (LODA) to operate certain aircraft holding limited category and experimental special airworthiness certificates for compensation or hire while providing flight training, checking, or testing.
The AC is available at the following website:
https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID119425558720250721180523.0001
The final rule (89 FR 80310), along with AC 91-94, provides comprehensive guidance on the FAA’s LODA issuance process, including application procedures, eligibility criteria, sample documentation, and conditions of use.