The pilot reported that, while in cruise flight, the Piper PA-22-108 experienced a total loss of engine power about eight miles from the intended destination. Unable to restart the engine, he subsequently ditched the airplane in a lake near Forsyth, Mo.
No fuel was found in the fuel system during the post-accident examination, however, the plane had been submerged for nearly a week before it was recovered from the lake.
Post-accident performance calculations indicated that it is likely that the engine lost power due to fuel exhaustion.
Although the pilot reported that he had completed preflight planning calculations (the actual paperwork was lost during the accident), the investigation determined that the wind aloft values that the he likely used in his preflight planning calculations were significantly different from the actual wind aloft values. As a result, the plane’s actual ground speed was significantly less than what the pilot would have anticipated.
He also reported that he completed the accident flight at less than 65% engine power, which would have increased the length of the flight and the amount of fuel used during it when compared to higher engine power settings.
The available cruise performance charts lacked true airspeed and engine speed data for operating below 65% engine power. Therefore, the pilot could not have estimated the total flight time and fuel required for the flight with a high level of accuracy.
Additionally, he reported that the mixture control cable had fractured during a previous flight and, to continue his cross-country trip, he safety-wired the carburetor mixture control arm in the full-rich position. As a result, he was unable to properly lean the fuel mixture during the flight.
However, it is unknown to what extent the pilot planned for this condition. Further, he made an unplanned stop at an airport located along his planned route of flight. The additional fuel consumed during this unplanned stop (taxi, engine run-up, takeoff, and climb to cruise altitude) would have further reduced the amount of fuel available to complete the accident flight.
The NTSB determined the probable cause as the pilot’s improper flight planning, which resulted in a total loss of engine power due to fuel exhaustion.
NTSB Identification: CEN14LA112
This January 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.