Cessna 310 N6602B accident near Coeur D Alene, Idaho

Probable cause

Improper maintenance of the landing gear system which resulted in a partial gear collapse during landing.

NTSB analysis

The airplane was on final approach for landing, with the landing gear extended, when the landing gear indication light in the cockpit started to flicker. After a few seconds, the light became solid. The pilot visually verified that all three landing gear were extended and then proceeded to land. Upon touchdown, the left main landing gear (MLG) collapsed. The airplane slid off the runway and came to rest in the adjacent field, resulting in substantial damage to the wings.

A postaccident examination of the landing gear system revealed several discrepancies, including missing cotter pins and other hardware, improper tension on the landing gear downlocks, and mis-rigging of the landing gear actuator.

Because the most recent maintenance for the landing gear system was documented 15 days before the accident, it is likely these discrepancies were not addressed during the maintenance (which included a main landing gear wheel, tire, and brake inspection). The most severe discrepancy was likely the mis-rigged condition of the retraction system, which would have allowed the left main landing gear to enter an overcenter position and collapse during landing.

Text from the NTSB. Open the NTSB docket for WPR20LA187 for the full record.