A gap in safety between experimental and certificated aircraft is widest on the first flight, and the early hours of flying in a new pilot’s hands. That is among the conclusions of a detailed analysis released by the NTSB on May 22 along with a set of recommended changes approved unanimously by the board.

Working in conjunction with organizations such as the Experimental Aircraft Association (EAA), pilots, builders and experimental aircraft manufacturers, analysts attempted to find root causes of a troubling disparity. While experimental amateur-built aircraft account for less than 10 percent of the U.S. GA fleet, such aircraft account for 15 percent of all accidents and 21 percent of the fatal accidents in 2011, the year studied in greatest detail.

Analysts and investigators drew on more than crashes: the EAA supported an online survey of more than 5,000 amateur builders and owners, whose input helped NTSB staff craft a set of 16 recommendations to improve safety. The agency published online an executive summary following the May 22 meeting, with the full report to be released later.

Many of the recommendations seek to address a lack of transition training and familiarity with experimental aircraft. The NTSB directed 12 of its recommendations to the FAA, calling for a more formalized approach to flight testing, and clarification of regulations governing flight instruction in experimental aircraft. The NTSB called on the EAA to help disseminate a list of instructors authorized to teach in experimental amateur-built aircraft.

The full list of recommendations can be found here.