Bell Helicopter Textron 206L-1 N38AZ accident near Breckenridge, Colorado

Probable cause

The pilot's failure to maintain directional control while maneuvering due to a loss of tail rotor effectiveness. Contributing to the accident was the pilot's failure to monitor wind direction while operating in the "Critical Wind Azimuth Area."

NTSB analysis

The helicopter was conducting external load operations at an estimated density altitude of 14,000 to 14,500 feet. While manuvering to the landing zone, the helicopter began to lose tail rotor effectiveness. The commercial pilot was unable to regain control of the helicopter prior to impacting sloping terrain. Substantial damaged was sustained to the helicopter's fuselage and the pilot was seriously injured. Using an estimate total gross weigh of 3,600 pounds (3,000 pounds for the helicopter plus internal load and 600 pounds for the external load), the helicopter would have been operating in the Area B section of the Out of Ground Effect (OGE) Hover Ceiling chart and is subject to the Critical Relative Wind Azimuth chart that lists a wind avoid area between 050-210°. This density altitude combined with the helicopter's weight placed the helicopter's performance in the "Critical Wind Azimuth Area." Convective activity in the area of the accident would have produced varying wind directions with gusts up to 30 knots.

Text from the NTSB. Open the NTSB docket for CEN09LA413 for the full record.