Amateur-built T-21 N450C accident near Endicott, New York

Probable cause

A partial loss of engine power for reasons that could not be determined, and the pilot's subsequent exceedance of the airplane's critical angle of attack during an attempted return to the runway, which resulted in an aerodynamic stall/spin at an altitude that precluded recovery.

NTSB analysis

According to a witness, the pilot of the experimental, amateur-built airplane had completed one takeoff and landing in the airport traffic pattern. Following the second takeoff, at an altitude about 300 ft above ground level, the witness heard the engine "pop." The airplane remained in a nose-high attitude as it entered a steep left turn as if to return toward the runway; the witness stated that the airplane then spiraled toward the ground. Another witness stated that he heard the accident airplane's engine power decrease as it climbed through about 300 ft after takeoff and the airplane subsequently entered a descending left turn before disappearing behind trees. Postaccident examination of the engine revealed no mechanical anomalies that would have precluded normal operation, and there was no evidence of fuel contamination. All major components of the airplane were located at the accident site, and flight control continuity was established from the cockpit to all flight control surfaces. Review of the airplane's logbook and a witness account indicated that, about 1 year before the accident, the pilot had experienced aerodynamic flutter of the rudders on at least two occasions and made subsequent airframe modifications as a result; however, there was no evidence to indicate that this contributed to the accident.

The airplane's steep descent before impact and the limited wreckage distribution at the accident site were consistent with an aerodynamic stall/spin. It is possible that the pilot may have experienced a partial loss of engine power or other engine anomaly (based on the witness statements) and, in response, attempted to complete a 180° turn back to the runway. During the turn, the pilot exceeded the airplane's critical angle of attack, which resulted in an aerodynamic stall/spin and a loss of control. The reason for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ERA19FA196 for the full record.