NTSB Identification: DFW06FA083.
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Nonscheduled 14 CFR
Accident occurred Tuesday, March 14, 2006 in Patterson, LA
Probable Cause Approval Date: 03/26/2007
Aircraft: Bell 206L-1, registration: N370RL
Injuries: 2 Fatal,2 Minor.
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.
Approximately 5 minutes after departing on a Title 14, CFR Part 135 air taxi cross-country flight, the helicopter had a loss of engine power while in cruise flight. The commercial helicopter pilot subsequently made a hard forced landing at an off-airport site comprised of tall vegetation and soft terrain. The helicopter came to rest in an upright position, and the two rear seat passengers were able to egress unassisted. Moments later, the helicopter was engulfed in flames. The wreckage path was oriented on a magnetic heading of 225 degrees, and the wind was reported as from 020 degrees at 12 knots. An examination of the engine at the accident site revealed that the fuel line to fuel nozzle "B" nut could be turned by hand, and did not contain a lock wire as required. All other fittings and nuts on the engine were found to be secure. A review of the helicopter's maintenance records revealed that a 50-hour fuel nozzle inspection was performed the evening prior to the accident flight. This inspection required the removal, disassembly, cleaning, inspection, reassembly, and reinstallation of the fuel nozzle. An interview with maintenance personnel revealed that fuel nozzle installation procedures found in the engine manufacturer's maintenance manual had not been followed. A tear down examination of the engine was performed. The engine examination revealed no preimpact anomalies. Investigators conducted operational tests on an engine of the same make and model. The tests were performed in an effort to determine what effect a loose fuel nozzle "B" nut would have on the engine's operation. The test revealed that the engine would experience a substantial loss of power that could conclude in a flame out. Testing further revealed that conditions would have been conducive for an in-flight fire. Investigators could not determine if the fire originated in-flight, or during the ground impact.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The improper installation of an engine fuel line fitting by other maintenance personnel, which resulted in a loose fitting and a loss of engine power during cruise flight. Factors associated with the accident are a tailwind, and the lack of a suitable site for a forced landing. Full narrative available
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