Air Tractor Inc AT-502 N1515P accident near Blackfoot, Idaho

Probable cause

A partial loss of engine power during takeoff for undetermined reasons.

NTSB analysis

The pilot reported that, during takeoff for a local aerial application flight, the airplane became airborne slightly beyond the normal rotation point. As the airplane approached the departure end of the runway, the engine did not develop enough power to maintain flight. The pilot stated that due to the amount of runway remaining, he was unable to abort the takeoff. He then lowered the nose in an effort to gain more airspeed but did not jettison the chemical load in the hopper. Subsequently, the airplane struck multiple trees beyond the departure end of the runway and came to rest upright. Company personnel reported that, per the pilot's request prior to the accident flight, the airplane was loaded with an amount of chemical that was similar to amounts that he had been using throughout the day. Postaccident examination of the engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Signatures observed on the engine's internal components exhibited characteristics of the engine developing power at the time of impact, likely in a high power range. The airplane was found to be within weight and balance limitations at the time of the accident. The reason for the engine to not develop sufficient power for the airplane to maintain a positive rate of climb could not be determined.

Text from the NTSB. Open the NTSB docket for WPR11LA278 for the full record.