Incident Summary
A flight lesson aimed at introducing single-engine operations to a dual student took place at an airport with an air traffic control tower. The airplane performed two touch-and-go landings before the instructor requested a full stop and taxi back, which was approved by the tower. After landing and taxiing to an intersection, the tower cleared the airplane for takeoff and for the option.
Witness Accounts
A ground witness reported hearing the airplane's engines rev up as if for takeoff, then idle, then rev again before the airplane departed. Several witnesses observed the airplane take off to the west. At an estimated altitude of 100 to 150 feet above ground level, the airplane pitched up steeply and executed a wing-over to the right. It then nosed straight down into the ground, bursting into flames upon impact.
Wreckage Examination
Examination of the wreckage revealed no anomalies. The elevator trim jackscrew assembly was found in a position equating to 10 degrees of nose-up trim.
Probable Cause
The source does not state a probable cause.