On August 12, 1995, a Piper PA-30-B (registration N8113Y) was involved in an aviation accident near Wickenberg, AZ. Investigators recorded the probable cause as: the pilot's improper emergency procedures. The pilot's diverted attention, and the magnetos clearance and timing were factors in this accident. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During touch-and-go practice, an aircraft experienced engine backfire on takeoff, descended, and was later found northeast of the runway. Post-accident examination revealed right engine magneto timing exceeded service limits.
Accident Overview
A pilot was conducting touch-and-go landings and takeoffs. During the final takeoff, a ground witness reported that an engine began to backfire. The airplane started to descend while the backfiring continued, and it eventually disappeared from the witness's view.
Another pilot, also practicing touch-and-go landings and takeoffs, observed the airplane lying northeast of the departure end of the runway.
Engine Examination
An examination of both engines found no evidence of any internal preexisting malfunctions or failures. However, the timing of the right engine's magnetos exceeded the manufacturer's service limits. According to an accessory repair technician, neither magneto was considered airworthy.