Aviation Accident Summaries

Aviation Accident Summary CEN20LA208

Fargo, ND, USA

Aircraft #1

N3869W

Piper PA32

Analysis

The flight instructor attempted to start the airplane for the instructional flight when the engine started and began to sputter a few seconds later. He moved the mixture control forward, but the engine quit. The instructor then saw black smoke emanating from the engine cowl. He continued cranking the engine in an attempt to draw the fire into the engine. The fire continued so the flight instructor ordered an evacuation of the airplane. The subsequent fire substantially damaged the engine compartment. Postaccident examination of the engine revealed the highest intensity heat and fire was near the engine driven fuel pump. The fuel pump subsequently leaked when it was pressurized with fuel. It is likely the failure of the engine-driven pump allowed fuel to exit and become exposed to the hot engine, which caused the fire.

Factual Information

On June 3, 2020, about 1400 central daylight time, a Piper PA-32-260 airplane, N386W, was substantially damaged when it was involved in an accident in Fargo, North Dakota. The flight instructor, student pilot, and one passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 instructional flight. The flight was planned to originate at Hector International Airport (FAR), Fargo, North Dakota, at 1400, with an intended destination of Park Rapids Municipal Airport-Konshok Field (PKD), Park Rapids, Minnesota. Upon startup during the preflight, a fire started within the engine compartment. The airplane sustained substantial damage to the engine mount and firewall. According to the flight instructor, he entered the airplane with two student pilots. One of the student pilots read through the checklist during the pre-flight process. The master switch was turned on, the rotating beacon was turned on, fuel pump was turned on, and the primer handle was pumped eight times. The instructor explained that is the amount of prime they had previously needed to start the airplane. The magnetos were then turned on and the starter pressed. The airplane engine began to turn slowly, as was “typical of this airplane,” and after about two revolutions of the propeller the engine started. The instructor stated the engine ran for about 3 seconds and began to sputter. He noticed the mixture had not been pushed in prior to start; that step was skipped over when reading the checklist. He pushed the mixture full forward, but the engine still quit. He noticed black smoke coming from the engine cowling. The instructor thought it was a carburetor fire; he pulled the mixture handle out and opened the throttle. He continued to crank the engine to “draw the fire into the engine.” Within a second or two he noticed fire coming from the cowling. Realizing the very slow RPM from the starter and the fact that the fire was already proceeding out of the cowling, he determined “there was no hope in extinguishing the fire with this procedure” and told the two students to evacuate the airplane immediately. The Federal Aviation Administration conducted a postaccident examination of the airplane. His inspection revealed areas of high intensity heat damage, “similar to holding a blow torch on one spot,” concentrated near the engine driven fuel pump. An aircraft mechanic pressurized the engine driven pump with fuel and the pump started leaking fuel immediately from the pump body. The pump would be activated during the engine start sequence which is when the pilot reported the fire began. According to maintenance records, the fuel pump was replaced on January 22, 2019, with a used fuel pump due to leakage. It was replaced a second time on November 29, 2019, with an overhauled unit.

Probable Cause and Findings

Failure of the engine driven fuel pump which led to a fuel leak and subsequent fire in the engine compartment.

 

Source: NTSB Aviation Accident Database

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