On August 7, 2005, a Mooney M20C (registration N6330Q) was involved in an aviation accident near Oro Valley, AZ. Investigators recorded the probable cause as: a loss of engine power due to the pilot's inaccurate fuel consumption calculations that resulted in fuel exhaustion. Contributing to the accident was the inaccuracy of the cockpit fuel gages which read 1/4 tank when empty. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
The pilot of an airplane made an emergency landing in desert vegetation after fuel exhaustion during the arrival pattern. No fuel was found in tanks; cockpit gauges showed 1/4.
Incident
While entering the arrival pattern at the destination, the airplane exhausted its fuel and the pilot executed an emergency landing short of the runway. The pilot had been airborne for about 5 hours 10 minutes. She had been managing the fuel system by switching tanks approximately every hour. The final switch to the right tank occurred 10 minutes prior to arriving at the destination airport. She overflew the destination airport and executed the prescribed entry. During a left-hand turn to enter the downwind leg, at 1,500 feet above ground level (agl), the engine began to run abnormally and then lost power. She diverted toward the crosswind runway and landed short of the runway threshold in desert vegetation.
Examination
An examination of the airplane revealed that neither the left wing fuel tank nor the right wing fuel tank contained fuel. The tanks were not compromised, and there was no evidence of fuel leakage. In this unfueled condition, both left and right cockpit fuel gauges read 1/4.
Fuel System Test
The airplane was fueled with 1 gallon of avgas in the left tank. The engine was started and ran satisfactorily.