NTSB Factual Report

On June 16, 2001, at 1230 mountain standard time, a Piper PA-28-181, N4299Q, was substantially damaged during a ground fire event at the Sedona Airport, Sedona, Arizona. The rented airplane was registered to and operated by Falcon Executive Aviation, Mesa, Arizona. Neither the private pilot nor his passenger were injured. Visual meteorological conditions prevailed for the personal flight operating under the provisions of 14 CFR Part 91, and no flight plan had been filed. The flight was originating at the time of the accident and was destined for Falcon Field, Mesa, Arizona.

The pilot provided the Safety Board investigator with a written statement. He stated that he and his passenger boarded the airplane after performing a standard preflight inspection. Although the runway was closed due to a disabled airplane, the pilot chose to taxi to the run-up area because he anticipated the disabled airplane would be removed when his run-up was complete. When the pilot completed the before takeoff checklist, the runway was not yet cleared, and he was informed that it would remain closed for about 20-30 minutes. Therefore, the pilot shut the engine down and waited.

When the runway reopened, the pilot started the engine. During the engine start, the pilot heard a pop, which he assumed was the engine backfiring. He proceeded with the procedure for engine fire during start by continuing to crank the starter, in an attempt to draw any potential fire back into the engine intake. The engine did not start and he saw smoke coming from the engine cowl. He instructed his passenger to go outside with a small fire extinguisher located in the front side pocket, and try to extinguish the fire with the handheld extinguisher. By the time the passenger got out of the airplane and extinguished the fire bottle, "heavy smoke" was observed emanating from the left side of the engine cowl. The pilot shutoff the fuel selector and retrieved another fire extinguisher, which was located under the co-pilot seat. The pilot extinguished his bottle in the fresh air inlet on the bottom of the engine cowl, but it had no effect on extinguishing the fire. About 2 to 3 minutes later, an individual from one of the airport services arrived with a medium sized fire extinguisher. That pilot expended this fire extinguisher into the fresh air inlet and around the exhaust area and the fire appeared to go out, only to break out into flames again a few seconds later. Their efforts to fight the fire were unsuccessful.

The person who brought the medium sized fire extinguisher informed the pilot that the fire department had been notified. The fire department arrived on scene 15 minutes later, and by this time, the airplane was completely engulfed in flames.

A review of Piper's Engine Fire During Start emergency procedures, revealed the pilot is instructed to attempt to extinguish the fire by attempting an engine start in order to draw the excess fuel into the induction system. If the fire is present before the engine has started, the pilot is to draw the fire back into the engine by moving the mixture control to idle cutoff, open the throttle, and turn off the electric fuel pump and fuel selector while cranking the engine.

Though Piper indicates that engine fires during start are "usually the result of overpriming," Glencoe's Seventh Edition of Aircraft Powerplants training manual indicates that backfiring can be caused by a number of pilot or maintenance related events. Some such events include sticking intake valves, ignition troubles, lean mixture settings, etc. The cause of the backfire was not determined.

NTSB Probable Cause

the induction manifold fire resulting from an engine backfire during engine start. The reason for the engine backfire was not determined.