On April 20, 2002, a Stinson 108-2 (registration N959D) was involved in an aviation accident near Helena, MT. Investigators recorded the probable cause as: Fracture of the left main wheel assembly during the takeoff roll. Factors include the use of a wheel assembly not approved for the accident airplane, and the use of an oversized tire. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During takeoff roll, the airplane began tracking left; the right main wheel assembly and landing gear strut collapsed. Post-accident examination revealed multiple fractures in the wheel and an unapproved assembly not listed on the Type Certificate Data Sheet.
Event Description
The pilot reported that shortly after applying takeoff power, the airplane deviated left of the runway centerline. While attempting to correct, the right main wheel assembly and right landing gear strut collapsed.
Post-Accident Examination
Examination of the wheel assembly and tire showed the outboard wheel subassembly fractured along the bead seat ring in multiple locations. The inboard wheel subassembly also exhibited multiple fractures, and the brake disc had partially separated from the wheel.
Aircraft Information
The Type Certificate Data Sheet for the airplane lists several approved wheel-brake assemblies. The wheel assembly installed on the accident airplane was not among the approved configurations. Furthermore, the installed wheel assembly was not approved for use with tires larger than size 7.00-6, but the airplane was equipped with 8.00-6 tires. The airplane's most recent annual inspection occurred on March 7, 2002.