On April 1, 2007, a Cessna 320E (registration N3424Q) was involved in an aviation accident near Stockton, CA. Investigators recorded the probable cause as: The right main landing gear was rigged so that gear tension terminated prematurely, preventing the downlock link from reaching its full over-center locked position. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
The right main landing gear collapsed while the aircraft was taxiing off the runway, following an annual inspection that included landing gear rigging. A subsequent inspection report identified that the gear had been rigged with premature tension termination, preventing proper downlock engagement, leading to overload failure of other components.
Incident Overview
After landing, as the aircraft was exiting the runway, the right main landing gear collapsed. The right wing subsequently struck the runway surface. The pilot reported that this was the first flight following an annual inspection during which the landing gear had been rigged.
Laboratory Examination
The pilot arranged for the failed components to be sent to a metallurgical laboratory for analysis. The owner submitted the findings from this laboratory to the Safety Board.
Inspection Findings
The inspection report indicated that the right main landing gear had been rigged in a manner that caused the gear tension to terminate prematurely. This condition prevented the downlock link from reaching its full over-center locked position. As a result, side loads on the landing gear were transmitted through other linkage components instead of through the downlock link. These other components were not designed to carry such loads and consequently failed in overload, leading to the collapse of the landing gear while the aircraft was taxiing off the runway.
Probable cause
The right main landing gear was rigged so that gear tension terminated prematurely, preventing the downlock link from reaching its full over-center locked position. This caused side loads to be transmitted through other components not designed for those loads, resulting in overload failure.