NTSB Identification: SEA98LA087.
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Accident occurred Thursday, June 04, 1998 in HAILEY, ID
Probable Cause Approval Date: 01/10/2000
Aircraft: Champion 7GCB, registration: N912CP
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The pilot, flying from the front seat, was aware of a tailwheel shimmy condition prior to the flight. Upon touchdown, the aircraft's tailwheel began to oscillate. Marks on the runway showed tailwheel tire scuffing from the touchdown area and beyond. A second solid scuff mark associated with the left wheel was observed as both scuff marks diverged left of the runway centerline. Post-crash examination revealed that the rear right brake-pedal had disconnected from the connecting rod to the forward right brake-pedal and the disconnection rendered the forward right brake-pedal unusable. The disconnection occurred at the rear right brake-pedal attach eye, and one separation surface was observed to be clean whereas the opposing side was dirty. Cracks were observed inside the attach eye radii, as well as the opposing end of the pedal. The right-main landing gear separated. Examination of the tailwheel assembly revealed that the hexagonal nut which holds the inner lock ring in place had become loose allowing the lock ring to shift. This allowed the two lock ring pins to shear, thus allowing the tailwheel to oscillate or 'shimmy' during roll.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The disconnection of the rear right-main brake pedal from the brake master cylinder, and the overloading of the right main landing gear. A factor was the oscillation of the tailwheel. Full narrative available
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