Cessna 172N N737TP accident near Elliott Key, Florida

Probable cause

The airplane’s vertical descent into water for reasons that could not be determined because postaccident airplane examinations revealed no mechanical anomalies.

NTSB analysis

The student pilot departed on a local, solo instructional flight. According to the flight instructor, the student was briefed to complete three takeoffs and landings and to stay in the airport traffic pattern. Instead, the student completed one takeoff and landing and then departed the airport traffic pattern. Witnesses reported seeing the airplane in level flight about 2 hours later over the ocean 20 miles from the departure airport. Two witnesses said that the airplane's nose "pitched up" momentarily before the airplane descended vertically at "full power." One witness described the sound of the engine as "wide open" and noted that it was accelerating throughout the descent. All of the witnesses said that the airplane went "straight down" and that it did not rotate.

Examination of the wreckage revealed damage consistent with a vertical descent at high speed and no preimpact mechanical anomalies. The autopsy report determined that the cause of death was "airplane crash." For the airplane to descend straight down, the forward pressure on the yoke must be increased proportionally with the increase in airspeed. If control positions remained constant, the dive would shallow out as it progressed.

Text from the NTSB. Open the NTSB docket for ERA14LA346 for the full record.