Flight Details
The aircraft was being flown on a routine flight check following the completion of an annual inspection. After takeoff, the pilot climbed to 800 feet, turned downwind, extended flaps to 30 degrees, and reduced airspeed to between 70 and 80 knots. The intention was to make a pass over the field to ensure it was clear before initiating a final approach for landing.
Pilot's Account
The pilot stated that upon entry to a runway heading, the aircraft "apparently entered an area of extreme thermo-lift causing right wing to rise suddenly causing momentary increase in bank and apparent accelerated stall causing aircraft to dive into ground."
Weather Conditions
The official temperature recorded at 0850 at Chicago Midway Airport, located 18 miles north, was 68 degrees Fahrenheit.