SEA95LA028

While cruising at 11,500 feet MSL, the aircraft experienced a complete loss of engine power. Being unable to regain power, the pilot elected to attempted a forced landing near Medicine Bow, Wyoming. The touchdown was successful, but the nose gear and right main gear collapsed during the landing roll on the rough/uneven terrain. Later investigation revealed that both magneto coils had shorted to the magneto housing. One coil had burned through its insulation, and the other showed signs of arcing through a number of cracks in its insulation.

On December 10, 1994, approximately 1130 mountain standard time (MST), a Piper PA-28-236, N4300V, experienced a gear collapse during a forced landing near Medicine Bow, Wyoming. The commercial pilot and his two passengers were not injured, but the aircraft sustained substantial damage. The personal pleasure flight, which departed Sheridan County Airport, Sheridan, Wyoming at 1000 MST, was being operated in visual meteorological conditions. The aircraft was on a VFR flight plan en route to Broomfield, Colorado at the time of the accident. Although the ELT was not activated by the accident sequence, the pilot turned it on after the accident in order to assist searchers in finding the aircraft.

According to the pilot, the flight was cruising at 11,500 feet MSL when the engine suddenly lost power. Being unable to regain power, the pilot attempted a forced landing in an open field about 12 miles southeast of Medicine Bow. The touchdown was successful, but the nose gear and right main gear collapsed during the landing roll on the rough/uneven terrain.

An FAA monitored teardown inspection was performed at Teledyne Continental's Atlanta facility, and it was determined that both magneto coils showed evidence of shorting to the magneto housing. The right coil had burned through its insulation, and evidence of electrical arcing was found on the adjacent surface of the housing. A number of cracks, with attendant electrical distress marks, were found in the insulation of the left coil, and evidence of electrical arcing was found on the housing adjacent to these cracks.