What happened
On November 27, 2023, a Piper PA-32R-301T, registration N4187Q, was conducting a night flight under visual meteorological conditions from Oneida, Tennessee, to Fairhope, Alabama. During the flight, the pilot began an uninstructed descent and subsequently declared an emergency, reporting a loss of engine RPM.
While in contact with air traffic control, the pilot inquired about landing at Northeast Alabama Regional Airport (GAD) in Gadsden, Alabama. The controller informed the pilot that the longer runway was closed and the shorter runway lacked lights due to ongoing work. The pilot was subsequently vectored toward Robbins Field Airport (20A) in Oneonta, Alabama.
As the aircraft continued to descend, the pilot reported that he did not have an airport in sight. The final ADS-B transmission occurred at 1746:34, showing the aircraft at 2,300 feet MSL. At 1748:02, the pilot reported a terrain warning while at 1,100 feet MSL. The aircraft subsequently impacted heavily wooded, mountainous terrain, resulting in a post-impact fire that burned several acres. The pilot sustained 1 fatal injury.
The investigation
Engine examination revealed that the loss of engine power was caused by mechanical failures within the accessory section. Investigators found that one pawl retaining rivet of the left magneto impulse coupling had failed due to fatigue and wear, which then caused the second pawlin retaining rivet to fracture from overstress. This led to a cascade of failures, including the fracturing of the left gear retainer assembly and damaged teeth on multiple gears, specifically the fuel pump idler gear assembly.
While the aircraft was equipped with an independent right magneto and an auxiliary fuel pump, the extent of the post-impact fire prevented investigators from determining the operational status or switch positions of these components at the time of the accident.