As part of the 2021 fixed wing Flying Qualities ground school, I provided a new lecture on the Bell X-2 Roll Coupling flight test accident.
The lecture reviewed the whole flight test program and examined in detail the last and record-breaking flight, where the X-2 became the victim of three distinct coupling modes, one leading directly into the next, eventually destroying the aircraft and killing the test pilot Capt. Milburn “Mel” Apt.
Reconstruction of the event from historical data included an analysis of the variation of key stability derivatives with increasing Mach number and how these contributed to the aircraft’s departure from controlled flight.
AT ITPS we strongly believe that the history of flight test and the lessons learnt from past projects is a necessary element in forming the culture and the mindset of future flight test professionals.