Thursday, February 16, 2017

Robinson R-44 II, Quicksilver Air, N74713: Accident occurred June 18, 2014 in Coldfoot, Alaska

Aviation Accident Final Report  -  National Transportation Safety Board:

Docket And Docket Items - National Transportation Safety Board:

Aviation Accident Data Summary -  National Transportation Safety Board:

Quicksilver Air Inc: 

Additional Participating Entities:

Federal Aviation Administration Fairbanks Flight Standards District Office; Fairbanks, Alaska 

NTSB Identification: ANC14CA042
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Wednesday, June 18, 2014 in Coldfoot, AK
Probable Cause Approval Date: 08/14/2014
Aircraft: ROBINSON HELICOPTER COMPANY R44 II, registration: N74713
Injuries: 3 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The commercial helicopter pilot reported that the purpose of the flight was to transport two technicians to a remote site in an area of mountainous terrain. The pilot fueled the helicopter and flew approximately 30 minutes to a staging area. After loading the two passengers and their gear, he flew to the planned landing zone (LZ), in a narrow box-valley at about 2,550 feet MSL. The proposed LZ was evaluated while performing an out-of-ground-effect hover, but the pilot determined the LZ was unsuitable. A second LZ was evaluated using the same process and also found unsuitable. 

While hovering out of ground effect, above a third potential LZ, the helicopter began to descend and the pilot added collective pitch to stop the descent. He said the low rotor annunciator horn then sounded and the helicopter continued to descend. In an attempt to avoid landing in an area of uneven terrain, the pilot said he opted to turn the helicopter to the right and downslope, while trying to override the engine governor to attain additional engine power. The helicopter's skids subsequently struck an area of uneven, down sloping terrain. During touchdown, the helicopter nosed down, pivoted to the left, and rolled onto its left side. The helicopter sustained substantial damage to the fuselage, tail boom and main rotor drive system. The pilot reported no preaccident mechanical anomalies with the helicopter that would have precluded normal operation.

The pilot characterized the down sloping wind conditions as light and variable.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot's failure to maintain adequate main rotor rpm while maneuvering at a low altitude, which resulted in an emergency landing on uneven terrain.

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