Beech B36TC N8234M accident near Santa Ynez, California

Probable cause

A loss of engine power during initial climb due to fuel starvation. Contributing to the accident were the pilot’s inadequate preflight inspection, his failure to properly diagnose the loss of engine power, and his failure to follow the appropriate emergency procedures.

NTSB analysis

A few days before the accident, the private pilot requested that the airplane be serviced with equal quantities of fuel in each wing tank. The ramp agent instead filled the left tank close to capacity and did not put any fuel in the right tank. The pilot was not aware of the discrepancy, and during the preflight inspection, he checked the fuel tank levels using the wing-mounted sight gauges. However, he misread the right tank quantity and continued the preflight inspection even though the fuel quantity gauges in the cabin did not match the sight gauges. The sight gauge design allows for the display of fuel quantity only when the tank is filled to between 25 and 35 gallons (about 1/2 to 3/4 full). However, when the tank is filled to 1/4 of its capacity or less, the tail of the gauge needle points to the 32 gallon (3/5 capacity) position. This most likely accounted for the pilot’s misinterpretation of the fuel level.

During the initial climb, with the right fuel tank selected, the engine lost all power. The pilot failed to recognize the fuel starvation condition and performed troubleshooting steps by memory before ultimately switching the fuel tank selector valve to the left tank, which was full. The pilot’s troubleshooting procedures included multiple activations of the auxiliary fuel pump on HI mode, which, according to the airplane manufacturer’s emergency checklist, was not the appropriate action for a fuel starvation condition. The use of the pump resulted in an excessively rich fuel mixture when the left tank was selected and prevented the engine from being restarted. The pilot then switched back to the empty fuel tank and performed a gear-up forced landing into a plowed field.

Text from the NTSB. Open the NTSB docket for WPR12LA246 for the full record.