Incident Overview
A pilot reported that after parachutists egressed from the airplane, he returned to the airport and noticed the absence of a green down-and-locked indication for the left main landing gear. The pilot then executed emergency procedures and performed two fly-bys over the runway.
Ground Personnel Observations
Ground personnel at the airport stated that the landing gear appeared to be down-and-locked from their visual inspection.
Landing and Collapse
During the landing roll, the airplane began to slide sideways. Subsequently, the right main landing gear began to collapse and eventually separated from the airplane. As the airplane slid to a stop, the left main landing gear also collapsed.
Post-Accident Examination
After the accident, the upper torque knee on the left main landing gear was found broken. The failure mode of the upper torque knee was not determined.
Official Findings
Probable cause: Landing gear collapsed for undetermined reasons.