NTSB Identification: CEN12LA039
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Friday, October 07, 2011 in South Pass 93A, GM
Probable Cause Approval Date: 11/26/2012
Aircraft: EUROCOPTER AS 350 B2, registration: N183EH
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.
During an engine start on a helipad, the helicopter's main rotor blade contacted the tailboom, which resulted in substantial damage to the tailboom. The reported wind about the time of the accident was about 23 knots. The pilot reported that when the wind was from the east, as it was at the time of the accident, wind contact with a generator room west of the helipad resulted in occasional updrafts on the helipad. An examination of the helicopter did not reveal any preexisting anomalies that would have precluded normal operation. In the helicopter's flight manual checklist for the "Checks Before Starting the Engine," the helicopter's cyclic is to be in the neutral position and the cyclic stick friction lock adjusted. Note 1 of the checklist states, "In strong wind, apply a little forward cyclic and accelerate the engine, up to approx. 320 rpm, as fast as in compatible with t4 limitations, then follow normal procedure." A review of accidents involving the same make and model helicopters, revealed that in all of the recorded tail boom strikes by main rotor blades during start, two conditions needed to be present: cyclic not centered and air turbulence pushing strongly on the main rotor blades.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Improper centering of the cyclic during a start in gusty wind conditions. Full narrative available
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