Incident Overview
During preparation for landing, the pilot lowered the landing gear and observed that all three green DOWN AND LOCKED lights were illuminated. Shortly thereafter, a thump was heard, originating from under the floor of the airplane. The pilot then noted that the nose landing gear light remained green, but the main gear lights had extinguished.
Landing and Collapse
The pilot proceeded with the landing without attempting to recycle the landing gear, concerned that doing so might cause further damage. Upon touchdown, the right main landing gear light illuminated, but the left indicator light remained unlit. The pilot allowed the airplane to roll out, avoiding braking and excessive steering inputs. About 200 feet from the taxiway turnoff, the left main landing gear collapsed.
Subsequent Damage
The left propeller struck the runway, causing the engine to stop. The left wing and horizontal stabilizer also struck the runway. The airplane made a left sliding turn for approximately 150 feet before coming to a stop on the side of the runway.
Post-Accident Examination
A post-accident examination by an A&P mechanic revealed that the down limit switch, which operates the landing gear mechanical stop, had malfunctioned. The switch was found bent in the up position. The gear motor continued to run, causing the gearbox to over-travel and pull on the landing gear rods, which retracted the landing gear.