Friday, September 1, 2017

Robinson R22 BETA, N7085K, registered to and operated by Bering Pacific Ranches Ltd: Accident occurred December 02, 2016 near Unalaska Airport (PADU), Dutch Harbor, Alaska

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

NTSB Identification: ANC17LA011
14 CFR Part 91: General Aviation
Accident occurred Friday, December 02, 2016 in Unalaska, AK
Probable Cause Approval Date: 11/14/2017
Aircraft: ROBINSON HELICOPTER R22, registration: N7085K
Injuries: 1 Minor, 1 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.

The commercial pilot of the helicopter stated that the purpose of the flight was to transport a telecommunications technician to a cattle ranch on an island. After departing from the airport, while flying overwater, the pilot observed a snow squall with near-zero visibility and decided to return to the airport. On the return trip, while flying in a mountainous valley, another snow squall moved into the area. He stated that due to the deteriorating flight conditions, he conducted a precautionary landing to remote, snow-covered terrain to wait for improved flight conditions. Once the squall passed, he continued to the airport. Several minutes later, another snow squall arrived, and the pilot decided to conduct another precautionary landing. During the landing sequence, the main rotor system downwash resulted in whiteout conditions, and the pilot was unable to recognize any topographical features. The main rotor blades impacted terrain and the helicopter rolled onto its left side. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot’s failure to maintain adequate clearance from terrain during a precautionary landing in whiteout conditions, which resulted in an in-flight collision with terrain. 

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Anchorage, Alaska

Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Bering Pacific Ranches Ltd: http://registry.faa.gov/N7085K

NTSB Identification: ANC17LA011 
14 CFR Part 91: General Aviation
Accident occurred Friday, December 02, 2016 in Unalaska, AK
Aircraft: ROBINSON HELICOPTER R22, registration: N7085K
Injuries: 1 Minor, 1 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.

On December 2, 2016, about 1200 Alaska standard time, a Robinson R-22 Beta helicopter, N7085K, collided with remote snow-covered terrain while landing, about 10 miles southwest of Unalaska, Alaska. The commercial pilot sustained no injury, the passenger sustained minor injuries, and the helicopter sustained substantial damage. The helicopter was registered to, and operated by, Bering Pacific Ranches Ltd., Calgary, Alberta, Canada, as a visual flight rules (VFR) flight under the provisions of 14 Code of Federal Regulations Part 91. Deteriorating visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The flight originated from the Unalaska Airport, Unalaska, about 1100.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on December 7, the pilot stated that the purpose of the flight was to transport a telecommunications technician to the Fort Glenn cattle ranch on Umnak Island. After departing from the Unalaska Airport, while flying overwater past Makushin Bay near Cape Starichkof, he observed a snow squall with near zero visibility. The pilot decided to return to Unalaska. On the return trip, while flying in a mountainous valley, a snow squall moved into the area. He stated that due to the deteriorating flight conditions, he conducted a precautionary landing to remote snow-covered terrain to wait for improved flight conditions. Once the snow squall passed, he departed to head back to Unalaska. Several minutes later, he encountered a second snow squall and decided to conduct another precautionary landing. During the precautionary landing sequence, whiteout conditions were present from the main rotor system downwash from the previous snow squall, and the pilot was unable to recognize any topographical features. The main rotor blades impacted terrain and the helicopter rolled onto its left side. Both occupants egressed from the wreckage, a personal locator beacon was activated, and the occupants were extracted from the accident site via a U.S. Coast Guard MH-65D helicopter. 

The helicopter sustained substantial damage to the fuselage, main rotor system, tail boom, and tail rotor system.

The pilot reported that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. 

PERSONNEL INFORMATION

In the NTSB Accident/Incident Reporting Form 6120.1, the pilot reported that he held a helicopter instrument rating in addition to instructor ratings for helicopter and instrument helicopter. He additionally reported 70 hours of simulated instrument flight time and no hours were reported for actual instrument flight time. 

AIRCRAFT INFORMATION

The helicopter had no onboard weather capability and it was not instrument flight rules-equipped and certified. The helicopter had a standard skid configuration with no emergency floatation system installed.

METEOROLOGICAL INFORMATION

The closest official weather observation station is located at the Unalaska Airport, about 10 miles northeast of the accident site. At 1200, an Aviation Routine Weather Report (METAR) was reporting, in part: wind 220° (true) at 18 knots, gusting 25 knots; visibility 10 statute miles; clouds and sky condition, broken clouds at 1,600 feet; temperature 37° F; dew point 27° F; altimeter 30.19 inHg.

SURVIVAL ASPECTS

The accident helicopter was not equipped, nor was it required to be equipped with an emergency locator transmitter. The pilot and passenger were not wearing flight helmets for the flight. The helicopter was equipped with 3-point restraint systems for the two seats.

ADDITIONAL INFORMATION

The Naval Research Laboratory has published the Forecaster's Handbook for the Bering Sea, Aleutian Islands, and Gulf of Alaska (1993). This document discusses snowfall and snow cover on the Aleutian Islands and states in part:


During winter, snow frequently covers the ground but the depth of coverage rarely exceeds 1 foot (30 centimeters). High winds, however, cause snow to drift so that depth at an individual location is highly dependent on topography. Some depressions may fill to depths exceeding 6 feet (1.8 meters), and other areas remain relatively free of snow. Because of the relatively mild temperatures, the snow is frequently of the wet, heavy type. Annual rainfall for the islands averages 40 to 50 inches (102 to 152 centimeters), and, again is heavily influenced by topography so that individual locations may have quite different rainfall amounts even though they are separated by only a short distance.

NTSB Identification: ANC17LA011
14 CFR Part 91: General Aviation
Accident occurred Friday, December 02, 2016 in Unalaska, AK
Aircraft: ROBINSON HELICOPTER R22, registration: N7085K
Injuries: 1 Minor, 1 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

On December 2, 2016, about 1200 Alaska standard time, a Robinson R-22 Beta helicopter, N7085K, collided with remote snow-covered terrain while landing, about 10 miles southwest of Unalaska, Alaska. The commercial pilot sustained no injury, the passenger sustained minor injuries, and the helicopter sustained substantial damage. The helicopter was registered to, and operated by, Bering Pacific Ranches Ltd., Calgary, Alberta, Canada, as a visual flight rules (VFR) flight under the provisions of 14 Code of Federal Regulations Part 91. Deteriorating visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The flight originated from the Unalaska Airport, Unalaska, about 1100. 

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on December 7, the pilot stated that the purpose of the flight was to transport a telecommunications technician to the Fort Glenn cattle ranch on Umnak Island. After departing from the Unalaska Airport, the pilot stated that while flying overwater via the Umnak Pass prior to reaching Umnak Island, he observed a snow squall. The pilot decided to return back to Unalaska and while flying in a mountainous valley, a snow squall moved into the area. He stated that due to the deteriorating flight conditions, he conducted a precautionary landing to remote snow-covered terrain to wait for improved flight conditions. During the precautionary landing sequence, white out conditions were present from the main rotor system downwash, and the pilot was unable to recognize any topographical features. The main rotor blades impacted terrain and the helicopter rolled onto its left side. Both occupants egressed from the wreckage, a personal locator beacon was activated, and the occupants were extracted from the accident site via a U.S. Coast Guard MH-65D helicopter. 

The helicopter sustained substantial damage to the fuselage and main rotor system.

The pilot stated that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. 

The closest official weather observation station is located at the Unalaska Airport, about 10 miles northeast of the accident site. At 1200, an Aviation Routine Weather Report (METAR) was reporting, and stated in part: Wind 220 degrees (true) at 18 knots, gusting 25 knots; visibility 10 statute miles; clouds and sky condition, broken clouds at 1600 feet; temperature 37 degrees F; dew point 27 degrees F; altimeter 30.19 inHg. 

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