Cessna 501 N501KM accident near Houston, Texas

Probable cause

The malfunction of the left main landing gear down lock, which resulted in a gear collapse upon landing.

NTSB analysis

On final approach to his destination airport, the pilot lowered the landing gear for a full stop landing. He received two of three green landing gear down position indicator lights. The left main landing gear light was not illuminated, and a warning horn sounded. The pilot recycled the landing gear and received the same result. The pilot queried the tower and another airplane to confirm that his landing gear were extended, and both told the pilot that they saw all three gear extended. Consistent with airplane manufacturer guidance, the pilot then performed maneuvers to generate lateral G-force on the landing gear in an attempt to get a gear locked indication on the left main gear, which was not successful. Upon landing, the left main landing gear collapsed, and the airplane veered off the runway, resulting in substantial damage to the left wing and underbelly of the airplane.

Examination of the airplane’s landing gear system revealed the internal down lock mechanism of the left main landing gear actuator malfunctioned. The cockpit gear position indicator lights functioned normally. There were no recent logbook entries concerning anomalies with the left main landing gear.

Text from the NTSB. Open the NTSB docket for CEN20LA185 for the full record.