Purpose: Know what tends to go wrong in your airplane. Compare US accident records for two piston types by accident category, phase of flight and severity, with registered-fleet rates, top NTSB findings and the latest accidents (currently no accident or registration data from outside the USA).
Data. NTSB aviation accident database (avall.mdb for 2008 on, Pre2008.mdb for 1982–2007) and the FAA Releasable Aircraft Database (current and deregistered aircraft), both bundled with this page, not fetched live. Aircraft are matched to the FAA registry by N-number and serial number to get the exact model; when no match exists the NTSB's make/model text is used. Included: certificated (non-homebuilt) piston airplanes from Cirrus, Diamond, Cessna, Piper, Beech and Mooney, US-registered, flights under Part 91. Excluded: incidents, Part 135/137 and public-use flights, ag and warbird types.
Categories. From 2008 on, the category is the NTSB's own "defining event," which follows the CAST/ICAO (CICTT) taxonomy. Before 2008 the NTSB used an older coding with no defining event; for those years this app maps the first listed occurrence to the nearest category. Those years are marked "derived" and use two extra labels (Weather encounter; Power loss, non-mechanical) where the old codes don't split cleanly.
Rates. "Registered aircraft" counts every airframe on the FAA registry at any time in the year, flying or not. Training aircraft fly many more hours per year than owner-flown aircraft, so per-registered-aircraft rates favor owner-flown types; no per-model flight-hour data exists. Registration counts before about 2011 include many aircraft no longer flying (the FAA's re-registration program, which ended 01-Jan-2014, cleared them out), so early-year rates read low. The range in grey is a 95% interval for random variation (Poisson).
Recent years. NTSB investigations take about two years; recent accidents may be preliminary, without probable cause or findings, and the latest months are incomplete.