The NTSB says the AT-6D that crashed in Lake Winnebago during the 2023 AirVenture likely stalled and spun into the water after getting too slow in a turn. The pilot and co-owner of the Texas Warbirds Museum, 30-year-old Devyn Reiley, and passenger Zach Colliemoreno, 20, were killed. “The airplane slowed to a speed consistent with its published accelerated stall speed, then entered a rapid descent,” the NTSB’s final report said. “A witness reported seeing the airplane in a flat spin to the right that continued until the airplane impacted the water.” The plane, part of the museum’s collection, was destroyed and ended up in 20 feet of water. Investigators couldn’t find anything wrong with the aircraft. The formal cause of the crash is listed as “the pilot’s failure to maintain airspeed while maneuvering, which resulted in the exceedance of the airplane’s critical angle of attack and an aerodynamic stall/spin.”
The plane took off just before 9 a.m. and reached 3900 feet before making a right turn and then a left. ADS-B data showed it slowed to 87 mph calibrated airspeed, and the stall speed would have been about 89 mph during the second turn, which was estimated to be about 1.8 G. The pilot had 33 hours on the type and had been checked out two months earlier.
I would like to know how they determined Calibrated Airspeed (CAS) based on ADS-B data. It would seem like that could solve a lot of the arguments about the stall speed limitations in MOSAIC.