Eurocopter AS 350 B2 N183EH accident near South Pass 93A

Probable cause

Improper centering of the cyclic during a start in gusty wind conditions.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for CEN12LA039 for the full record.