Flight Details
The flight’s purpose was for the instructor-pilot to prepare the first and second pilots for upcoming FAA Part 135 competency and proficiency checks. The first pilot obtained a weather briefing and filed an instrument flight rules (IFR) flight plan. The instructor-pilot was listed as pilot-in-command. After takeoff, the airplane proceeded to its designated practice area.
Maneuvers
According to the cockpit voice recorder (CVR), the pilots practiced various maneuvers under the instructor-pilot’s direction, including steep turns and approaches to stalls. The first pilot then was asked to demonstrate an approach-to-landing stall. During the conversation, the first pilot inquired if the instructor-pilot had ever performed stalls in the airplane, to which the instructor replied it had been a while. The first pilot mentioned having done stalls in a Lear before. The instructor recalled stalling a JetStar during a FAR 135 ride. Flaps were extended and landing gear lowered. Digital electronic engine control (DEEC) recorded a power reduction to idle. The stall was initiated from 5,000 feet altitude. The stick shaker activated, and shortly after, the recording ended.
Witness Observations
A consensus of 25 witnesses reported the airplane flying at low altitude and performing “erratic maneuvers.” One witness observed the airplane appearing to stop in midair before pitching nose down. Some witnesses described a spin, others a flat spin, and one said the airplane fell “like a falling leaf.” The airplane impacted marshy terrain in a nose-down, wings-level attitude.
Wreckage Examination
Examination revealed the landing gear was down and flaps set to 25 degrees. Both engines showed compressor/turbine section blades gouged and bent opposite rotation direction, with rotational scoring marks on both cases. No other discrepancies were noted.
Probable Cause
The official probable cause stated that the first pilot failed to maintain aircraft control and adequate airspeed. Contributing factors included performing intentional stalls at too low an altitude to allow safe recovery, the pilot’s failure to add power during recovery attempts, and the flight instructor’s inadequate supervision of the flight.