Grumman American Avn. Corp. AA 1C N9556U accident near Hemet, California

Probable cause

The pilot’s failure to ensure that sufficient fuel was available for the flight, which resulted in a total loss of engine power due to fuel exhaustion.

NTSB analysis

The private pilot reported that the airplane was last refueled and operated about 1 month before the day of the accident. He added that, on the morning of the accident, he believed the airplane still had about 17 to 18 gallons of fuel for the flight. The pilot mentioned that the airplane's fuel float gauges were not accurate; therefore, he looked inside of the left fuel tank from the filler cap and observed fuel. He did not check the right fuel tank because the style of tank restricted his view of any fuel. He departed the airport with the left fuel tank selected. After practicing standard maneuvers, the engine hesitated for a second. The pilot switched to the right fuel tank, which resolved the issue, but he turned back toward the airport. About 1 minute later, he switched to the left fuel tank and continued to fly at full power, which led him to believe fuel was in that tank. One to 2 minutes later, the pilot switched back to the right fuel tank and climbed to 8,000 ft, circled the town once, and then proceeded back toward the airport; the engine then suddenly lost power. The pilot attempted emergency procedures and troubleshooting to no avail. The pilot located a suitable field for the emergency landing; however, during the landing roll on the soft, dry, and rocky terrain, the airplane nosed over and then came to rest inverted.

Recovery personnel removed a small amount of fuel from the left auxiliary fuel tank, but the right auxiliary fuel tank and the main fuel tanks were empty. In addition, there were no observable breaches in the fuel tanks nor smell of fuel at the accident site. Given the pilot knew the airplane's fuel gauges were not accurate, he should have ensured that the airplane had sufficient fuel for the flight and his failure to do so led to the subsequent exhaustion of the fuel supply and total loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR17LA018 for the full record.