What happened
On January 31, 2023, at approximately 11:45 Pacific standard time, a Cessna 175, registration N9235B, was involved in an accident near Hayden, Idaho. The aircraft was being operated under Part 91 regulations for instructional purposes.
During the landing roll, while the pilot receiving instruction was slowing the aircraft to exit the runway via taxiway B, the airplane began an abrupt turn to the right. The pilot attempted to correct the movement by applying full left rudder and left brake, but the aircraft continued the right turn and underwent a ground loop. The pilot and flight instructor were not injured.
The investigation
Following the event, the crew taxied the aircraft back to their hangar, where they discovered substantial damage to the left wing, the left horizontal stabilizer, and the left side of the elevator. The right main landing gear leg was found to be misaligned, and the gearbox assembly was fractured.
An examination of the right main landing gearbox assembly by the NTSB Materials Laboratory revealed fatigue cracks located within the hollow slot of the assembly. The fracture surfaces outside of the fatigue zone showed coarse features, which are characteristic of an overstress event.