Accident Overview
On July 28, 2022, at 1438 central daylight time, a Piper PA-32RT-300T, registration N3027J, was substantially damaged when it collided with trees and terrain near Dallas, Texas. The pilot, the sole occupant, sustained serious injuries. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Emergency Landing
The pilot reported to air traffic control (ATC) that the engine was running rough and declared an emergency. ATC provided radar vectors to Dallas Executive Airport (RBD), Dallas, Texas. The pilot subsequently advised that he would be unable to reach RBD and intended to land in trees. The airplane came to rest approximately 0.5 miles southwest of RBD.
Postaccident Examination
Examination of the engine revealed a dual magneto housing both left and right magnetos in a single casing. The magneto case bore a yellow tag identifying it as a Continental Motors, Inc. type D6LN-3000, part number 10-682560-13, serial number G199915GR, and a blue tag from a Part 145 repair station. All four magneto case screws were loose prior to opening. The cam follower for the right side was melted, preventing proper contact point clearance. The left side had a contact point clearance of 0.008 inch, while the manufacturer's specification is 0.016 ±0.002 inch. The magneto capacitors were tested and found within specifications.
Magneto Bench Tests
During an initial bench test, the magneto produced no ignition on the right side and very intermittent ignition on the left. Swapping test leads did not resolve the issue, and the left-side cam follower began to melt. After re-gapping the left contact point to 0.018 inch and using good capacitors with bypass leads, the left side functioned normally. Reconnecting the original capacitors resulted in intermittent ignition. Connecting a direct ground lead to each capacitor bypassing the magneto case restored normal ignition; removing the ground wire caused arcing and melting of the cam follower. Corrosion was found on the inner and outer portions of the left capacitor case, which provided grounding to the capacitor.
Teledyne Continental Service Bulletin (SB) 651 warns that high resistance between the capacitor and magneto will destroy the contact assembly, leading to loss of ignition and engine power. It notes that arcing at points due to high resistance causes overheating and melting of the nylon cam follower.
Maintenance Records
The tachometer indicated 2,876.6 hours at the time of the accident. The last annual inspection was dated July 2, 2021, at tachometer time 2,876.3 hours. An invoice from May 22, 2021, at tachometer time 2,876.2 hours, documented the magneto's removal and replacement for a 500-hour inspection. No corresponding entries were found in the engine logbook, as required by regulation. An Airworthiness Approval Tag (FAA Form 8130-3) for the magneto's 500-hour inspection stated that the installer must comply with SB651.