NTSB Identification: LAX99FA317.
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Accident occurred Saturday, September 25, 1999 in PHOENIX, AZ
Probable Cause Approval Date: 05/17/2001
Aircraft: Kaman HH-43F, registration: N100PL
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
Ground witnesses reported seeing the helicopter disintegrate in-flight, about 250 feet above ground level. The helicopter impacted the ground in a nearly inverted attitude, scattering rotor blade fragments on both sides of a canal. The ex-military, medium lift helicopter with twin intermeshing rotors was en route to perform an off-airport lift operation. It operated in the 'restricted' category and was required to fly over unpopulated areas. At the time of the accident, it was flying parallel with a canal. Examination of the wreckage revealed that the fixed horizontal stabilizer left outboard leading edge attach fitting had fractured and exhibited evidence of a pre-existing crack. A second attach fitting aft of the leading edge attachment was also fractured. Additionally, the operator had installed automotive dampers in lead-lag positions on the rotor blades.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Failure of the horizontal stabilizer left outboard forward attach point because of a previously existing crack that resulted from inadequate maintenance inspection by the operator. A factor was the use of automotive parts. Full narrative available
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