Accident Sequence
The flight instructor (CFI) reported that the aircraft had completed two touch-and-go landings without incident. On the next landing, the aircraft "suddenly yawed to the left" and the gear warning horn began to sound, indicating that the landing gear was no longer down and locked. The CFI stated he took control from the multi-engine student pilot and attempted to slow and regain control.
The left main landing gear collapsed, causing the nose to yaw left, then right, which resulted in the collapse of the right main landing gear. The aircraft exited the runway and struck a runway light before coming to rest off the runway surface.
Witness and Supervisor Accounts
The CFI stated that just prior to the accident, he heard a report of windshear from an aircraft to the north. He also noted that the aircraft had performed normally before the accident. However, a tower supervisor reported that he observed the aircraft touch down about 1,500 feet down the runway and travel about halfway down before leaving the runway. He stated that he did not observe any other aircraft experiencing problems on the runway or in the traffic pattern, and there were no reports of windshear during that period.
Aircraft Condition
The CFI attributed the gear collapse to side loads that weakened the gear during the yaw event. No other mechanical issues were reported prior to the accident.
Outcome
The aircraft came to rest off the runway after striking a runway light. The extent of damage to the aircraft was not specified in the available information.