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GAA16LA031 · Airbus AS350 B2

26 Oct 2015 · Deadhorse, AK, United States

Great Slave Helicopters Airbus AS350 B2 · Accident: VFR encounter with IMC on approach

From Deadhorse, AK to Deadhorse, AK

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Event

NTSB case
GAA16LA031
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
Unknown
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Instrument Meteorological Cond

Airbus AS350 B2

Aircraft type
Airbus AS350
Category
Helicopter
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
C-GSLY
Onboard fatalities
Unknown
Route
From Deadhorse, AKTo Deadhorse, AK
Aircraft age
About 21 years (built 1994)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Approach
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
VFR encounter with IMC
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft oper/perf/capability
  • Environmental issues › Conditions/weather/phenomena
  • Environmental issues › Physical environment
  • Personnel issues › Action/decision
  • Personnel issues › Psychological

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

According to the noninstrument-rated commercial pilot, he was flying the helicopter, which was not instrument flight rules capable, to the landing site to pick up a crew of four seismic workers. Before the accident, he conducted a preflight risk assessment, which noted that the area was conducive to whiteout conditions and that visibility was between 1 and 3 statute miles. The assessment fell within the "low risk go flying" category, and a visual flight rules company flight plan was filed. The pilot reported that, while en route to the landing site, the weather began deteriorating and that he encountered an area with flat light conditions over snow-covered ground. The pilot then slowed the helicopter and stayed low to the ground. While slowing down to land, blowing snow from the main rotor downwash subsequently reduced the visibility to whiteout conditions with no ground reference, which likely led to the pilot experiencing spatial disorientation. The helicopter's right skid then contacted the ground, and the helicopter slid right and then rolled onto its right 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 has issued safety recommendations noting the importance of pilots being instrument proficient and of aircraft operating in such conditions being equipped with radar altimeters to enhance situational awareness; the accident pilot was not instrument rated and the accident helicopter was not equipped with a radar altimeter. Although the pilot was conducting the flight for a Canadian operator, which would not have been subject to these recommendations, this accident demonstrates the importance of pilots and helicopters being properly equipped to handle operations in such conditions.

Probable cause

The noninstrument-rated pilot's continued visual flight into adverse weather conditions, which resulted in spatial disorientation, and his subsequent failure to maintain terrain clearance while attempting to land in flat light and whiteout conditions.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record GAA16LA031
Event ID
20151027X81925
Case number
GAA16LA031
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 2015-10-27.
  • API snapshot SHA-256: 528d2a54607af23afb4c41d8c51a9cbd45a812b407b091b0739f31addcf5e8b5; retrieved 2026-09-16T02:55:45.408Z.