Forced Landing on Highway Due to Suspected Fuel Vapor Lock

Casualties unknown • Ardmore, AL, US

A Piper aircraft experienced engine power loss during initial climb in high temperatures, leading to a forced landing on an interstate highway to avoid traffic.

What happened

The pilot was conducting a flight that involved an initial climb phase shortly after takeoff. At an altitude of approximately 150 feet above ground level, the engine lost power. This event occurred shortly after the pilot turned off the fuel boost pump. With the engine no longer providing thrust, the pilot initiated a forced landing procedure.

The pilot identified a nearby interstate highway as a potential landing site. To minimize the risk of striking vehicles on the road, the pilot delayed the descent slightly to find a clearer path. This decision resulted in a hard landing on the pavement. No information is available regarding injuries or fatalities from this specific account.

The investigation

Post-accident examination of the aircraft revealed that the engine was capable of operating normally. A test run conducted after the incident showed no mechanical problems with the engine itself. This suggests that the power loss was not due to a mechanical failure of the airframe or propulsion system components.

Findings

Several environmental and operational factors contributed to the event. The ambient temperature at the time of the accident was approximately 90 degrees Fahrenheit. The airport elevation was recorded at 920 feet mean sea level, resulting in a calculated density altitude of approximately 3,200 feet.

The aircraft had been fueled with 87 octane automotive gasoline. According to Federal Aviation Administration records, the airplane was not Supplemental Type Certified (STC) to operate on auto gas. Furthermore, Piper Aircraft issued Mandatory Service Bulletin #855, dated January 14, 1987, which explicitly prohibits the use of auto fuel in Piper airplanes. The suspected cause of the power loss was identified as fuel vapor lock, likely exacerbated by the high density altitude and the use of unauthorized fuel type.

Safety message

Pilots must ensure that the fuel type used in their aircraft complies with manufacturer specifications and regulatory certifications. Using automotive gasoline in aircraft not specifically certified for such use can lead to severe operational hazards, including vapor lock and engine failure.

Probable cause

Fuel vapor lock resulting from the use of 87 octane automotive gasoline in an aircraft not certified for such fuel, combined with high density altitude conditions.

Frequently asked questions

What happened in the 1987-08-05 Piper PA-25-235 accident near Ardmore, AL?

A Piper aircraft experienced engine power loss during initial climb in high temperatures, leading to a forced landing on an interstate highway to avoid traffic.

What aircraft was involved and where did it happen?

The accident on 1987-08-05 involved a Piper PA-25-235, registration N9867P, operated by Towe Brothers, at Ardmore, AL.

What was the probable cause of the accident?

Fuel vapor lock resulting from the use of 87 octane automotive gasoline in an aircraft not certified for such fuel, combined with high density altitude conditions.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X31709. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

Loading the flight search…