Incident Details
The accident involved a maintenance test flight conducted under Title 14, CFR Part 91, to test the airplane's navigation instrumentation. The pilot, who held an airline transport certificate, reported that upon returning from the flight, the tower requested an expedited landing due to traffic. The pilot extended the flaps and landing gear and checked the nose gear using a mirror attached to the left engine. The nose gear appeared to extend normally in the mirror.
Landing Gear Collapse
Upon touchdown, all three landing gear assemblies collapsed. The airplane sustained structural damage to the bottom of the fuselage, stringers, and bulkheads.
Post-Incident Examination
The director of operations stated that the airplane was taken to a maintenance facility, where landing gear extension and retraction tests were performed. No anomalies were detected during those tests. Photographs provided by the operator showed no damage to the left or right main landing gear tires, wheels, or landing gear leg doors. However, the photographs revealed abrasions and scratches on the exterior of both main landing gear wheel doors, oriented parallel to the fuselage's longitudinal axis. These marks were consistent with ground contact while the gear was in the closed (retracted) position. Similarly, abrasions and scratches parallel to the longitudinal axis were observed on the exterior of both nose wheel doors.
Operator Suggestion
In a written statement, the operator suggested that the landing gear unsafe warning horn should be wired through the audio panel to improve audibility for pilots wearing noise-attenuating headsets.