Piper PA 22-150 N9975D accident near Kernville, California

Probable cause

The pilot’s exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall/mush.

NTSB analysis

The airline transport pilot reported that, shortly after takeoff for a personal, local flight, during which he applied full throttle, as the airplane reached about 100 ft above ground level (agl) or less, and with usable runway behind the airplane, he noted that the engine power was decreasing, and that the airplane was not climbing as expected. Despite the pilot’s checking the controls and confirming they were in their correct positions, the airplane continued to lose altitude. He realized that the engine was not producing sufficient power to climb to or maintain 75 ft agl and added that he maintained a “high deck angle” because he was “trying to maintain lift without stalling.” He then turned toward an open clearing for an emergency landing as the airplane continued to lose altitude. During the turn, the main landing gear wheels clipped a tree right before the clearing, followed by the airplane nosing over and coming to rest inverted.

The passengers reported that the airplane departed midfield with a “very high…angle of attack,” which did not fluctuate even during the stall, and that he never lowered the airplane’s nose. One of the passengers stated that the engine sounded normal and ran at full power throughout the flight.

The airframe and engine examinations revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. The damage to both propeller blades exhibited leading edge gouging, S-bending, torsional twisting and chordwise striation along the length of the blade, which is consistent with the production of engine power. Despite the pilot’s reports about an engine issue, based on the witness statements and engine examination results, the engine likely did not experience any in-flight issues. Rather the pilot’s maintaining a high pitch angle throughout the flight likely resulted in his exceedance of the airplane’s critical angle of attack and a subsequent aerodynamic stall/mush. Because the airplane’s current empty weight was not available for review, gross weight at the time of the accident was not determined. Additionally, due to the modifications that had been made to the airplane, no performance information was available to review that accurately characterized the airplane’s expected performance during the attempted takeoff.

Text from the NTSB. Open the NTSB docket for WPR17LA088 for the full record.