Airbus AS350 accident near Deadhorse, Alaska, October 27, 2015
On October 27, 2015 at about 1:03 am local time, a 1994 Airbus AS350 (helicopter), registered CGSLY, was substantially damaged in an accident during approach near Deadhorse, Alaska. It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 27, 2015 · about 1:03 am local time
- Place
- Deadhorse, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Airbus AS350 B2, built 1994
- Registration
- CGSLY · no longer on the register · serial 2771
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- VFR encounter with IMC during approach defining event
- Loss of visual reference during approach
- Controlled flight into terrain or object (CFIT) during approach
- Roll over during post (impact)
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring environment › Pilot
- cause Personnel issues › Psychological › Perception/orientation/illusion › Spatial disorientation › Pilot
- cause Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- cause Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Whiteout › Effect on personnel
- cause Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Low visibility › Effect on personnel
- cause Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Below VFR minima › Effect on personnel
- cause Environmental issues › Conditions/weather/phenomena › Ceiling/visibility/precip › Snow › Effect on operation
- cause Environmental issues › Physical environment › Terrain › Snowy/icy terrain › Effect on operation
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Altitude › Not attained/maintained
- Personnel issues › Experience/knowledge › Experience/qualifications › Total instrument experience › Pilot
- Aircraft › Aircraft oper/perf/capability › Aircraft capability › Instrument flight capability › Attain/maintain not possible
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 3,643 hours in all; 1,984 in this make and model; 127 in the last 90 days; 22 in the last 30 days; 3,531 as pilot in command
- Last flight review: July 1, 2015
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 17,167.2 hours
- Last inspection: 100-hour inspection, September 6, 2015
- Maximum gross weight: 4,961 lb
- Seats: 6
- Landing gear: fixed
- Engine: Turbomeca Arriel 1D1 (turboshaft); 12,092 hours total
The flight
- Departed from: Deadhorse AK
- Destination: Deadhorse AK
Weather at the time
- Light: daylight
- Wind: from 360° at 3 knots
- Visibility: 5 statute miles
- Sky: overcast at 1,200 ft
- Temperature: 21°F (-6°C), dew point 18°F (-8°C)
- Altimeter: 30.13 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on March 8, 2016. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Pilot's Statement | PDF, 1 page | View Download |
| 3 | Nts Safety Recommendations A-02-33 to A-02-35 | PDF, 7 pages | View Download |
| 4 | Accident Photos (Courtesy of Operator) | PDF, 4 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.