Amateur-built RV-6 N420PW accident near Cullman, Alabama

Probable cause

The pilot’s inadequate planning, which resulted in fuel exhaustion and a total loss of engine power during the initial climb. Also causal was the pilot’s exceedance of the airplane’s critical angle of attack while attempting to return to the runway after takeoff, which resulted in an aerodynamic stall/spin, loss of control, and impact with terrain.

NTSB analysis

Witnesses reported that, during the airplane’s initial climb, when it reached about 350 ft above the ground, they heard loud “pop” and a loss of engine power. The witnesses watched as the airplane entered an immediate “sharp left banking turn” in what appeared to be an attempt to return to the airport. The airplane “stalled and went into a left spiral downward turn.” The airplane completed two turns before impacting the ground on airport property adjacent to the taxiway.

The position of the airplane’s fuel selector as found would have supplied fuel to the engine from the left fuel tank; however, both of the airplane’s fuel tanks were breached during the accident and no evidence of fuel was found in either. There was no post-crash fire and there was no residual fuel noted at the accident site. The traces of fuel that were recovered from the airplane’s fuel system were absent of water. Otherwise, no evidence of preimpact mechanical failure or malfunction was noted during the examination of the recovered airframe and engine. The airplane’s recent fueling and flight history could not be definitively determined from available evidence other than that the airplane had last been fueled at the accident airport just over 1 month before the accident, and that the pilot had flown it on at least one trip in the intervening time.

Toxicology testing performed on the pilot identified cocaine in urine, but there was no evidence that any active cocaine remained in the pilot’s body. THC, the primary psychoactive component of cannabis, was not found; however, its active metabolite was in urine at very low levels. Therefore, the pilot was not directly impaired by his drug use at the time of the accident; whether he was feeling any effects from withdrawal could not be determined. Overall, it is unlikely that the pilot’s drug use contributed to the circumstances of this accident.

Based on the available information, the circumstances of the accident are consistent with a loss of engine power due to fuel exhaustion, 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.

Text from the NTSB. Open the NTSB docket for ERA20FA063 for the full record.