Main Landing Gear Collapse After Incomplete Extension During Landing

Event Description

The pilot was returning to the airport after a local maintenance flight. During the before-landing cockpit checks, the pilot did not detect that the landing gear had not fully extended. After touchdown, at approximately 70 knots, both main landing gear legs collapsed. The nose gear remained extended throughout the event. The rear fuselage and left horizontal stabilizer subsequently contacted the concrete pavement.

Examination Findings

Following the incident, the operator conducted an examination of the aircraft's hydraulic power pack. The examination revealed that the electric pump motor was inoperative. According to the operator's analysis, the failure of the power pack before the end of the gear extension cycle would result in a fully extended nose gear and a partial extension of the main landing gear legs.