Incident Overview
On an unspecified date, a Piper Aerostar 601 (registration N3645D) was arriving at an airport while a Bell 412 helicopter (registration N78S) was departing. The pilot of the Aerostar reported that the nose gear indicator light did not illuminate to confirm the nose landing gear was down and locked. The helicopter crew heard the transmission and observed the Aerostar as they crossed beneath its approach path, noting that the nose gear appeared extended. The Aerostar flew past the tower, and tower personnel also reported the nose gear appeared extended.
Inflight Inspection
After the Aerostar was cleared to turn downwind, the helicopter offered to join for a closer look, and the Aerostar captain accepted. During the join-up, the helicopter converged from the left rear and then indicated they would pass around the right side to examine the aircraft. They reported that everything appeared normal. Shortly thereafter, the two aircraft collided and crashed to the ground.
Investigation Findings
Investigators found no mechanical reason that would have caused the accident. None of the pilots had received training for flight in close proximity to another aircraft. There were indications that the captain of the Aerostar lacked training in aircraft systems and that his employer lacked oversight by the Federal Aviation Administration (FAA). The emergency procedure section of the Aerostar flight manual did not contain information on emergency gear extension.
Casualties and Injuries
All three occupants of the Aerostar and both pilots of the helicopter were killed. Four people on the ground sustained injuries, one of them serious.
Probable Cause
The poor judgement by the captain of the airplane to permit the inflight inspection after he had determined to the best of his ability that the nose landing gear was fully extended, the poor judgment of the captain of the helicopter to conduct the inspection, and the failure of the flightcrew of the helicopter to maintain safe separation. Contributing to the accident was the incomplete training and checking that the flightcrew of N3645D received from Lycoming Air Service and the FAA principal operations inspector assigned to the operator.