Accident Sequence
On October 20, 2022, at about 1010 Pacific daylight time, a Cessna 140, registration N55DC, was substantially damaged in an accident near Georgetown, California. The pilot, a student on a local solo practice flight, was not injured.
The pilot reported returning from a 1-hour flight and entered the downwind leg for runway 16 at 1,000 ft above ground level on a 45° entry. With the throttle, trim, and flaps set for landing, he maintained 65-70 mph on a stable approach. After crossing the runway numbers, he reduced engine speed to idle at 65 mph and touched down on the centerline. The airplane bounced, and the pilot floated down the runway to decelerate.
During the landing roll following the second touchdown, the right wing banked upward 30°–40°. Full right aileron was applied but unable to level the wings. The airplane veered left; the pilot applied full power to abort. The airplane departed the left side of the runway, the left wing contacted vegetation, and the airplane spun 180° before coming to rest. The right main landing gear leg and wheel separated and were found about 70 ft away near a slope.
Pilot Report
The pilot stated no issues with flight controls but noted uncertainty about the cause. He speculated that the right main gear separation could have caused the right wing to rise abruptly, or that a freak gust of wind might have been responsible. He was unsure if the gear separation resulted from an attachment failure or occurred during the accident sequence.
Examination Findings
According to the airplane parts manual, the main landing gear legs are attached to the fuselage structure with a bolt, washer, and nut. Examination of the accident airplane revealed that the landing gear bolt remained in place with its nut and washer, but the bolt head had separated and was missing. A portion of the landing gear support assembly was fractured and partially separated.
The National Transportation Safety Board materials laboratory examined the components. The fracture features of the bolt were consistent with ductile overstress from a shear overload, with no evidence of preexisting damage. The forward end of the landing gear support assembly outboard attachment was fractured at two locations on the lower support. The upper side was deformed downward near the forward attachment, and the outboard flange was fractured. The downward deformation at the forward end of the lower support was consistent with wheel loading in the aft direction, indicating an applied load sufficient to exceed the yield strength of the material.