NTSB Identification: LAX08IA032
14 CFR Part 91: General Aviation
Incident occurred Tuesday, December 04, 2007 in Fresno, CA
Probable Cause Approval Date: 12/24/2008
Aircraft: Robinson R22 Beta, registration: N805EH
Injuries: 2 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
Just as the helicopter touched down while performing a hovering autorotation, the certified flight instructor (CFI) heard a loud 'snap’ coming from the right side. The CFI took the controls from the student and attempted to neutralize the anti-torque pedals, but reported that they were stuck in place, with the right pedal in the forward position. He reduced the engine rpm’s to 75 percent, and attempted to move the pedals to no avail. At that point, he instructed the student to start the shutdown procedures. Following a normal shutdown, they exited the helicopter, and began to inspect the cause of the stuck anti-torque pedal. Both the CFI and student observed a broken metal structure adjacent to the restraining block that retains the anti-torque pedals. The CFI reported that it appeared to be the actual metal structure that the entire pedal assembly bolts to. The helicopter inspection revealed that the right-hand support bracket (part number A359-2) of the tail rotor control system had failed. The operator reported that the airframe had a total time of 13,000 hours. The helicopter manufacturer reported that they had been aware of other failed support brackets on helicopters with over 7,500 hours in service. As a result, the manufacturer increased the thickness of the support bracket material, and changed their overhaul procedures requiring replacement of the A359-1 and -2 support brackets at overhaul for all R22 and R44 models. The manufacturer also issued service bulletin (SB) SB-97 for the R22 and SB-63 for the R44, which require the addition of a safety tab on the older thinner support brackets.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: Failure of the tail rotor system support bracket during landing. Full narrative available
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