Incident Overview
During the landing roll, both main landing gear of an Aero Commander collapsed approximately 100 feet down the runway. The subsequent skidding ground off the belly skin and damaged several structural airframe components.
Observations During Landing
One of the observers in the airplane, who was also a pilot, reported seeing three green landing gear indicator lights, indicating that the gear was down and locked. Both the observer and the pilot visually confirmed that the landing gear was down prior to touchdown. The observer noted that the pilot maintained one hand on the control yoke and the other on the throttle throughout the landing and landing roll.
Post-Incident Examination
A physical inspection of the landing gear revealed no anomalies. When the aircraft was placed on jacks, the landing gear functioned normally. Additionally, the actuators were tested on a test bench and functioned properly.
Aircraft System Details
The Aero Commander uses hydraulic pressure to keep the landing gear locked in the down position. The landing gear handle has two positions: gear up and gear down.
Conclusion
No probable cause was identified in the source material. The investigation did not indicate any mechanical failure or human error contributing to the collapse.