Accident Details
On June 28, 2022, at approximately 1146 Pacific daylight time, a Cessna 120, registration N2056V, was substantially damaged when it was involved in an accident near San Carlos, California. The pilot and passenger were not injured. The airplane was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
According to the accident pilot, the airplane had been flown two days earlier by another pilot from Anderson, California, to San Carlos Airport (SQL). That pilot reported refueling with 15 gallons of fuel and flying back to SQL using the right fuel tank, estimating the flight duration as about 1 hour and 40 minutes. He noted that the tanks were not completely filled; 15 gallons was sufficient for the flight. As he approached SQL, he switched to the left fuel tank and landed without incident.
On the day of the accident, the accident pilot reported having 14 gallons of fuel onboard. He taxied to the runway using the right fuel tank, which he recalled was full. After an engine runup, he departed runway 30. When the airplane reached about 400 feet above ground level, the engine rpm decayed to approximately 1,800. The pilot executed a 180° turn toward runway 12 but was unable to reach the runway and landed on the airport perimeter road. The airplane bounced, impacted a fence, and came to rest upright on the airport transient parking ramp. The pilot stated that, after the accident, the right fuel line was severed and pouring out fuel. He reported that he attempted to turn the fuel selector off but inadvertently turned it in the wrong direction before exiting the wreckage.
Aircraft Information
The accident airplane is equipped with two 12.5-gallon fuel tanks, each with a float-type sight gauge. The fuel selector valve has three positions: LEFT, RIGHT, and OFF. The airplane owner’s manual states, in part, “Set fuel tank selector to fullest tank. (Do not take off on less than 1/4 tank).”
A postaccident examination by a Federal Aviation Administration inspector revealed that the fuselage was substantially damaged. Examination of the recovered airframe and engine found no evidence of any preexisting mechanical malfunction that would have precluded normal operation. The position of the fuel selector valve at the time of the accident could not be determined.
The investigation did not identify specific performance information for the O-200-A engine installed on the Cessna 120, particularly fuel burn rates. However, the Fuel Flow Limits vs RPM chart from the O-200-A overhaul manual indicates fuel burn rates vary between 4.5 and 9 gallons per hour at 2,050 and 2,750 rpm, respectively. At 2,350 rpm, fuel burn would be about 6 gallons per hour.