NTSB Factual Report

On July 31, 2004, at 1519 eastern daylight time, a Piper PA-28RT-201T, N77782, piloted by a private pilot, was destroyed during a post-impact ground fire following a loss of engine power and subsequent forced landing near Plymouth, Michigan. The airplane experienced the loss of engine power while on initial climb from runway 18 (2,556 feet by 75 feet, dry asphalt) at the Canton-Plymouth-Mettetal Airport (1DS). Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and one passenger were not injured. One passenger reported minor injuries. The local area flight was originating at the time of the accident.

The pilot reported he had landed at 1500 and shut down the engine for a few minutes prior to loading his two passengers for a local flight. The pilot stated the airplane contained 35 gallons of 100 low-lead aviation fuel prior to the accident flight.

The pilot reported the engine "shuddered" during takeoff roll and he aborted the takeoff. The pilot stated he then performed an engine run-up check and the engine "felt fine." The pilot reported he taxied onto runway 18 and set the engine power to 2,500 rpm and 38 inches of manifold pressure. The pilot stated the airplane became airborne and experienced a loss of engine power while on initial climb.

The pilot reported he switched fuel tanks, but there was no increase in engine power. The pilot stated the airplane descended under some power lines as he maneuvered the airplane to land on a nearby road. The pilot reported the airplane impacted a road sign prior to coming to stop and an on-ground fire engulfed the airplane shortly thereafter.

Federal Aviation Administration (FAA) inspectors performed the on-site investigation. The engine was removed from the accident airplane and mounted on a compatible airframe for an operational engine test. The engine started and idled without anomalies. The engine was then accelerated to 2,200 rpm which yielded approximately 80 lbs of oil pressure. The engine was then shut-off using the mixture idle cut-off. There were no anomalies noted with the engine during the operational test.

The closest weather reporting station to the accident site was located at the Willow Run Airport (YIP), Detroit, Michigan, about 7.4 nautical miles (nm) southeast of the accident site. The airport is equipped with an Automated Surface Observing System (ASOS). The following weather conditions were reported prior to and at the time of the accident:

At 1453 edt: Wind 230 degrees at 11 knots, visibility unrestricted at 10 statute miles (sm), few clouds at 5,000 feet above ground level (agl), temperature 28 degrees Celsius, dew point -01 degrees Celsius, altimeter setting 29.90 inches-of-mercury.

According to FAA publication AC 65-12A, fuel normally remains in a liquid state until it is discharged into the air stream and changes into a vapor. Under certain conditions the fuel may vaporize in the lines, pumps, or other fuel components. The vapor pockets formed by the premature vaporization can restrict the fuel flow through units that were designed to handle liquids rather than gases. The resulting partial or complete interruption of the fuel flow is called vapor lock.

Transfer of heat from the engine tends to cause vaporization of fuel in the lines and the pump. This tendency is increased if the fuel in the tank is warm, commonly as a result of high atmospheric temperatures. Vapor lock can become serious enough to block the fuel flow completely and stop the engine. Even small amounts of vapor in the inlet line can restrict the fuel flow to the engine driven pump and ultimately reduce its output pressure.

NTSB Probable Cause

The loss of engine power at a low altitude due to a fuel flow restriction caused by vapor lock. Factors to the accident included the high atmospheric temperature and the road sign that the airplane impacted during the forced landing.