Flight Profile
According to radar data, the training flight departed at approximately 0820. The airplane flew south and climbed to 6,000 feet mean sea level (msl). About 20 minutes later, while maneuvering, the airplane descended and stabilized at 5,400 feet. However, airspeed decreased to about 60 knots indicated airspeed (KIAS). Subsequently, the airplane entered a rapid descent in a near-vertical flight path.
Witness Observations
Around 0840, witnesses near the accident site observed the airplane in a flat spin prior to ground impact.
Training Context
The training syllabus for the respective lesson included the following topics: Maneuvering at Critically Slow Airspeed; Emergency Operations (Engine-Out); and Maneuvering with One Engine Inoperative. Additionally, review of the flight instructor's daily planner for that lesson revealed, "Hold, Stalls, Short T/O/Landing."
Aircraft Performance Reference
Review of a Beech B55 manual revealed that the minimum speed for directional controllability with one engine out was 78 KIAS.