American Aviation AA 1 N5757L accident near Boynton Beach, Florida

Probable cause

The pilot's inadequate preflight fuel planning, which resulted in a total loss of engine power due to fuel exhaustion, and his exceedance of the airplane’s critical angle of attack following the loss of engine power, which resulted in an aerodynamic stall and loss of control.

NTSB analysis

Radar data indicated that, after departure, the pilot climbed the airplane to about 1,700 feet mean sea level (msl) in a gradual right turn. The airplane then began to descend, and its groundspeed decreased until radar contact was lost. The last radar return indicated an altitude of 550 feet msl and a ground speed of about 43 knots near the accident site. A witness reported that the airplane's wings appeared to "waggle" up and down, and the airplane suddenly appeared to go inverted. The airplane’s nose pointed at the ground, and the airplane began to corkscrew rapidly while losing altitude and disappeared behind a tree line. Another witness heard what she thought sounded like a boat having engine trouble, then heard a loud thump.

No evidence of any preimpact failures or malfunctions of the airplane or engine were discovered that would have prevented normal operation. The propeller blades did not exhibit any rotational signatures, consistent with the engine not producing power at the time of impact. There was no evidence of residual fuel inside either of the fuel tanks, the fuel selector valve, or the mechanical fuel pump, and the carburetor float bowl contained only about 2 drops of fuel. There was no odor of fuel on-scene, and no observed fuel blight near the wreckage.

The airplane’s most recent documented annual inspection was about 4 years before the accident. An acquaintance of the accident pilot reported that the pilot, who was a mechanic, had been working on the airplane for about 1.5 years. The acquaintance communicated with the pilot 3 days before the accident, during which the pilot reported that he flew the airplane and that the airspeed indicator seemed to be indicating “high” and that the stall warning horn activated below 85 mph. The pilot reported that he “didn’t feel like [the airplane] was stalling but it did feel slow.” Review of maintenance records did not reveal any entries pertaining to the pitot-static system.

Based on the available evidence, it is likely that the pilot did not verify the fuel quantity before he departed on the accident flight, which resulted in a total loss of engine power due to fuel exhaustion. It is also likely that, following the loss of engine power, the pilot failed to maintain airspeed and exceeded the airplane’s critical angle of attack, which resulted in an aerodynamic stall and loss of control. The extent to which the reported airspeed indicator/stall warning anomaly may have contributed to the accident could not be determined based on the available information.

Text from the NTSB. Open the NTSB docket for ERA20FA119 for the full record.