Left Main Landing Gear Axle Fracture During Landing Roll Results in Ground Loop (N86727)

Event Description

The left main landing gear axle fractured and collapsed during the landing roll, resulting in a ground loop that caused substantial damage to the gearbox. The fracture occurred in the vicinity of a weld on the axle.

History

An entry in the airplane's logbook indicated that the airplane had sustained a hard landing approximately 15 years before the accident. The logbook entry stated that maintenance technicians inspected the axle using the dye penetrate method. No logbook entry noted that the axle had been replaced.

Inspection Findings

The manufacturer's representative inspected the axle and reported that several items did not conform to the type design. The representative concluded that the axle had been cracked and rewelded, and the weld did not conform to specifications. The weld at the base plate had a larger radius than specified, which resulted in a flat surface that was insufficient to allow proper seating of the heads of the bolts that mounted the wheel to the axle. The manufacturer's representative stated that the axle failed in the weld heat affected zone due to improper repair.