Cessna 177 N30309 accident near Falmouth, Kentucky

Probable cause

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

NTSB analysis

The pilot was flying the airplane as a favor to the previous owner and delivering it to the new owner. As part of his preflight inspection he used a wooden stick with graduated markings that he found in the airplane to determine the fuel level, and estimated each tank had about 12.5 gallons, which was more than enough for the intended flight. About 40 to 45 minutes into the flight, while flying at 3,000 ft mean sea level, the pilot noticed a slight drop of engine rpm which he thought was carburetor ice. He applied carburetor heat which restored the engine rpm, and about 3 to 4 minutes later, he noted the engine rpm had "quite a bit more rpm decrease, and the engine then quit." He maintained best glide airspeed and was unable to restore engine power. He maneuvered for a forced landing in a pasture. During the landing roll the airplane nosed over.

Postaccident examination found both fuel tanks empty and there was no evidence of browning of vegetation beneath the resting position of either wing, nor a smell of fuel by a first responder. About 2 ounces and 4 ounces of blue colored fuel consistent with 100 low lead were drained from the carburetor float bowl and airframe fuel strainer, respectively. There was no evidence of fuel leaks from either wing, fuel cap, or fuel vent system. Following recovery of the airplane a temporary fuel supply was plumbed into the fuel supply line at each wing root and the engine was started and operated normally with no discrepancies noted. Given this information it is likely that the loss of engine power was most likely the result of fuel exhaustion.

While the pilot believed there was 12.5 gallons of fuel in each fuel tank at the start of the flight, a mechanic who performed the last annual inspection that was signed off 2 days before the accident reported that each tank had an estimated 6 gallons when the inspection began, and that the amount of fuel at the start of the accident flight was likely slightly less due to post maintenance engine operations. Therefore, it is likely that the amount of fuel in both fuel tanks at the start of the accident flight was about half of what the pilot believed was onboard based on his assessment using utilizing the wooden sticks he found in the airplane.

Text from the NTSB. Open the NTSB docket for ERA20LA245 for the full record.