Cessna 120 N2056V accident near San Carlos, California

Probable cause

The total loss of engine power for undetermined reasons.

NTSB analysis

The accident pilot reported that, 2 days before the accident, the airplane was flown uneventfully by another pilot to the destination airport using the right fuel tank. The pilot who previously flew the airplane reported that he had refueled the airplane with 15 gallons of fuel before that flight, which lasted about 1 hour and 40 minutes; he used the right tank for that flight. He did not indicate that the tanks had been completely filled, noting that 15 gallons was all he needed for the flight. As he approached the destination, he switched to the left fuel tank and landed uneventfully.

According to the accident pilot, after conducting a preflight inspection on the day of the accident, he taxied the airplane out to the runway using the right fuel tank. He recalled that the right tank was full of fuel, which would be inconsistent with the right tank’s fuel state if the previous flight had been flown using the right tank. Following an engine runup, he departed. As the airplane was about 400 ft above ground level, the engine rpm decayed to about 1,800 rpm. The pilot performed a 180° turn but was unable to make it to the runway and landed on an airport perimeter road. The airplane bounced, impacted the fence, and came to rest upright on the airport transient parking ramp. The pilot stated that, after the accident, he observed the right fuel line was “severed” with “pouring out fuel.”

Postaccident examination of the airplane revealed that the right fuel line from the lower door frame structure had separated from the fuel fitting. Examination of the recovered airframe and engine revealed no evidence of any preexisting mechanical malfunction that would have precluded normal operation.

Although the investigation did not identify performance information for the O-200-A engine installed on the Cessna 120 specifically for fuel burn, given the fuel burn of the O-200-A, and estimated flight time, the previous flight would have used about 10 gallons of fuel. This would place the fuel level in the fuel tank below 1/4 tank, which would prohibit takeoff according to the airplane owner’s manual. Although the pilot may have inadvertently used the wrong fuel tank for takeoff, which could have unported the fuel tank and interrupted the subsequent fuel delivery to the engine, the investigation could not determine the position of the fuel selector valve at the time of the accident. The reason for the total loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for WPR22LA242 for the full record.