Pilot Debrief

ROBINSON HELICOPTER R22 near Unalaska, AK — 2016-12-02

Final reportANC17LA011
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Date
2016-12-02
Location
Unalaska, AK, USA
Aircraft
ROBINSON HELICOPTER R22
Registration
N7085K
Category
Helicopter
Highest injury
Minor
Fatalities
0
Phase of flight
Approach

Probable cause

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.

NTSB narrative

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.

Analysis

Primary failure mode
Controlled flight into terrain
First missed decision gate
Pilot could have chosen to land earlier before encountering whiteout conditions.

NTSB coding

Evidence available

  • Photos
  • 3 docket documents
View NTSB final reportView NTSB docket

Docket documents3

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