Accident Overview
On November 18, 2022, at approximately 0745 eastern standard time, a Piper PA28-181, registration N8129M, was substantially damaged during a fire near Manassas, Virginia. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor and a student pilot were not injured.
Events Leading to the Fire
The flight instructor and student were preparing for a flight at Manassas Regional Airport/Harry P. Davis Field (HEF). The instructor reported that he primed the engine with fuel several times and attempted to start it in cold weather. The engine nearly started but did not maintain power and stopped. A second attempt yielded the same result. After waiting several minutes, he primed once and tried again; the engine shut off after about 4 seconds. During a fourth attempt without primer, white smoke emanated from the engine compartment. The instructor shut off the fuel valve and electrical equipment, grabbed a fire extinguisher, and exited the airplane. The smoke intensified, and a nearby mechanic instructed him to aim the extinguisher into the engine air intake to suppress any developing fire, which was ineffective.
Fire Progression and Response
The smoke continued to increase, followed quickly by fire from the engine compartment. The fire intensified and engulfed the front of the airplane within about 5 minutes before airport fire rescue services arrived and extinguished it.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector examined the wreckage. The fire consumed the engine compartment and entire cockpit and cabin, with additional thermal damage to the wings. Examination revealed electrical arcing damage to the alternator wire. Electrical pitting was found on the engine mounts, and the alternator wire exhibited features consistent with electrical arcing. The clamp securing the wire was severely damaged, melted, and appeared oversized. Damage was noted at the junction of the wire and clamp, which was in close proximity to a fuel line.
Maintenance Records Review
A review of maintenance records for the preceding 36 months did not reveal any items associated with the alternator or wires.