Quest Aircraft Company Llc KODIAK 100 N10PZ accident near Westport, Massachusetts

Probable cause

A failure to achieve a positive climb rate after takeoff for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any mechanical malfunctions or anomalies that would have precluded normal operation.

NTSB analysis

During departure from the 1,635-foot-long turf runway, the airplane impacted rocks and trees past the runway end. The pilot reported that he could not recall the events of the accident. One of the four passengers reported that he heard the engine advance to takeoff power "normally" and that he believed that the airplane became airborne before impact. Review of the manufacturer's performance data revealed that, given the atmospheric and loading conditions on the day of the accident, the distance required to take off and clear a 50-foot obstacle was about 920 feet. Examination of the flight control system revealed no mechanical malfunctions or anomalies that would have precluded normal operation.

Examination of the engine revealed significant circumferential rubbing, frictional heat discoloration, and material smearing signatures in the power section consistent with the presence of engine power at the time of impact. In addition, the compressor discharge air (P3) line pneumatic "B" nut fitting at the fuel control unit was visibly loose, and the "B" nut could be moved by hand. Further examination revealed that the No. 4 gearbox bolts and washers had been pulled from their threaded seats, likely during the impact sequence. The engine operated normally during postaccident functional checks. To determine the effect of the loose "B" nut fitting on the engine operation, the P3 line was manually manipulated to simulate takeoff vibrations, and the fitting was loosened to the extent possible; however, neither action affected the engine operation.

Text from the NTSB. Open the NTSB docket for ERA13LA360 for the full record.