The NTSB says a high-speed pitch-up "consistent with an ostentatious display" snapped the wing of a Cessna 337 and resulted in the deaths of all five people onboard at Farmingdale, N.J., on Feb. 15, 2010. The board also said data recovered from the Skymaster's GPS showed the aircraft was going about 160 knots when witnesses reported it pitched up steeply. The aircraft was placarded with a maximum maneuvering speed of 135 knots. But while the pilot's "failure to adhere to the airplane's operating limitations" was the official cause of the crash, the NTSB also said a lack of oversight by the FAA on the interaction of multiple STCs on the crash plane may have played a role.
This is a companion discussion topic for the original entry at https://www.avweb.com/news/pilot-actions-multiple-stcs-cited-in-skymaster-crash