Piper PA34 N456AG accident near Gainesville, Texas

Probable cause

The pilots’ failure to maintain airspeed while on final approach with asymmetric engine power, which resulted in a loss of control.

NTSB analysis

The flight instructor and pilot receiving instruction were conducting a training flight in the multi-engine airplane, which included several takeoffs and landings. Flight track data indicated that, just before the accident, the airplane was on a 1/2-mile final approach for landing about 250 ft above ground level. The airplane subsequently impacted the ground about 1,500 ft left of the approach end of the runway in a left-wing low attitude. A post-impact fire ensued.

Examination of the left engine propeller showed indications of low or no power; the right engine propeller displayed evidence of moderate or higher power at the time of impact. The left engine No. 2 cylinder fuel injector nozzle was plugged with an unknown substance. Fire damage precluded further determination of mechanical factors related to the asymmetric engine power at the time of impact.

The accident airplane’s engines had been recently replaced and since replacement, both engines had experienced loss of power events during ground operations. Maintenance actions included adjusting the fuel mixture idle setting and a ground test run, during which the problem could not be duplicated. A witness stated that, immediately before departing on the accident flight, the airplane’s left engine lost power and was restarted. Several flight instructors voiced concerns with the company’s inadequate maintenance practices and stated that there were self-induced pressures to complete training flights.

Review of the pilot’s training records indicated difficulty with maintaining airplane control during simulated one engine inoperative flight, and deficient language skills that resulted in a previous event during which another flight instructor experienced difficulty taking control of the airplane from the pilot.

Evidence at the accident site was consistent with asymmetric engine power at the time of the accident, but whether there was an actual loss of left engine power or if the approach was being conducted with a simulated loss of left engine power could not be determined. The position of the wreckage left of the runway and the airplane’s impact in a left-wing-low attitude is consistent with a loss of control due to a failure to maintain minimum control airspeed (Vmc) during the landing approach.

Text from the NTSB. Open the NTSB docket for CEN19FA238 for the full record.