NTSB Identification: SEA04LA108.
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Accident occurred Wednesday, June 16, 2004 in Bend, OR
Probable Cause Approval Date: 12/28/2004
Aircraft: Cessna 421B, registration: N332CC
Injuries: 3 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.
Shortly after applying power for the takeoff roll, the airplane pulled to the right. The pilot reduced power and applied corrective action to the left side brake, however the braking action had no affect and the airplane continued off the side of the runway. The nose gear subsequently collapsed. Inspection of the left side landing gear and brake assembly found that the caliper side pressure plate was cocked and signs of metal to metal gouging on the brake disc was present, and that two of the pads (on the caliper side pressure plate) were missing. Maintenance records indicated that the aircraft had been signed-off for an annual inspection and that the description of work performed indicated that the brakes and tires had been serviced. The aircraft had flown a one hour flight since the annual inspection. During that flight, one takeoff and one landing was accomplished without incident. The accident flight was the second flight after the inspection. Inspection of the nose gear found that the right side of the nose gear trunnion fractured off from the main body in two separate pieces at the lug transition radius. A visual inspection of the fracture surface found multiple origins consistent with fatigue cracking. The fatigue region initiated at the lug radius on the lower side of the lug and propagated toward the interior consuming approximately 5% of the cross-sectional area, with the remaining region being overstress. The Materials Engineer that inspected the trunnion reported that even though the lug contained pre-existing cracking, it appeared that the failure of the component was the result of a single large overload event.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: On ground encounter with terrain during the takeoff roll as a result of the left side brake not operating. Inadequate maintenance inspection, overload of the nose landing gear and soft terrain were factors. Full narrative available
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