Liberty Aerospace Incorporated XL-2 N516XL accident near Merritt Island, Florida

Probable cause

The failure of the pilots to maintain airspeed while maneuvering, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall. Contributing to the accident was the loss of engine power for a reason that could not be determined by the postaccident examination, which was limited due to impact damage.

NTSB analysis

According to a friend of the airplane's owner, the purpose of the flight was for the owner to check out another pilot in the airplane. It could not be determined which pilot was flying the airplane at the time of the accident. Review of uncorrelated radar data indicated that the flight departed and maneuvered in the local area for about 26 minutes before the accident occurred. One witness stated that the airplane was about 200 ft above ground level when it entered a turn, and then its nose dropped and it descended to the ground. Two other witnesses reported seeing the airplane descending in a nose-down attitude. The witnesses provided conflicting information as to whether or not the airplane's engine was producing power. Examination of the accident site indicated that the airplane impacted in a steep descent. The witness observations and the impact geometry are consistent with the pilots failing to maintain adequate airspeed while maneuvering, resulting in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.

The propeller blade signatures were consistent with the engine not producing power at impact. Engine parameter data downloaded from the full authority digital engine control's (FADEC) data recording device revealed normal rpm, cylinder head temperature, and fuel pressure readings from takeoff to the end of the recorded data, and no FADEC fault codes were recorded. However, the recorded data ended before the loss of control occurred. Postaccident examination of the engine powertrain, fuel distribution block, and fuel injectors revealed no evidence of preimpact failure or malfunction. Both of the engine's electronic control units sustained impact damage that precluded operational testing. Although the auxiliary fuel pump was determined to have been inoperative for a long period of time before the flight due to separation of one electrical wire near the pump, the engine-driven fuel pump was operational and capable of providing adequate fuel to the engine to sustain engine power. The investigation could not determine the reason the engine was not producing power at impact.

Text from the NTSB. Open the NTSB docket for ERA14FA282 for the full record.