NTSB Factual Report

**This report was modified on July 27, 2016. Please see the docket for this accident to view the original report.*

On October 26, 2015, about 1703 Alaska daylight time, an Airbus AS350B2, Canadian registration C-GSLY, collided with terrain during an approach to a remote landing site in the Franklin Bluffs, about 29 miles south of Deadhorse, Alaska. The commercial pilot was not injured. The helicopter was registered to and operated by Great Slave Helicopters Limited, Yellowknife, Northwest Territories, Canada under the provision of a North American Free Trade Agreement, 14 Code of Federal Regulations Part 91, Specialty Air Services certificate of authorization. White out meteorological conditions prevailed in the landing site and a company visual flight rules flight plan was filed. The flight originated from a staging and camp complex located between the James W. Dalton Highway (Alaska Route 11) and the Sagavanirktok River, about 5 miles southwest of the accident site.

According to the pilot, he was flying 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. He 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. He reported that, while slowing down to land, blowing snow from the main rotor downwash reduced the visibility to white out conditions with no ground reference. The helicopter's right skid then contacted the ground, and the helicopter slid right and rolled onto its right side, sustaining substantial damage to the main rotor system, fuselage, and tail boom.

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

PERSONNEL INFORMATION

The pilot, had a Canadian commercial pilot license, and reported that he had no instrument rating. The pilot did not report any instrument flight time (actual or simulated) on the NTSB Form 6120.1 Pilot/Operator Aircraft Accident/Incident Report.

AIRCRAFT INFORMATION

The pilot reported that the helicopter had no radar altimeter or ground proximity warning system installed. The helicopter was not instrument flight rules capable and had no onboard weather capability.

ADDITIONAL INFORMATION

National Transportation Safety Board Safety Recommendations A-02-33 to A-02-35

The National Transportation Safety Board (NTSB) issued Safety Recommendations A-02-33 to A-02-35 to the Federal Aviation Administration (FAA) on October 7, 2002. These Safety Recommendations originated from ANC99FA073, involving an Airbus AS350BA near Juneau, Alaska on June 9, 1999 resulting in seven fatalities. The probable cause for this accident is listed as;

The pilot's continued visual flight rules flight into adverse weather, spatial disorientation, and failure to maintain aircraft control. Factors associated with the accident were pressure by the company to continue flights in marginal weather, and the "flat" lighting leading to white out conditions. Additional factors were the pilot's lack of instrument experience, lack of total experience, inadequate certification and approval of the operator by the FAA, and the FAA's inadequate surveillance of the emergency instrument procedures in use by the company.

Safety Recommendation A-02-33 (open – unacceptable response as of September 11, 2014) states;

Require all helicopter pilots who conduct commercial, passenger-carrying flights in areas where flat light or white out conditions routinely occur to possess a helicopter specific instrument rating and to demonstrate their instrument competency during initial and recurrent 14 Code of Federal Regulations 135.293 evaluation check flights.

Safety Recommendation A-02-34 (closed – unacceptable action as of September 11, 2014) states;

Require all commercial helicopter operators conducting passenger-carrying flights in areas where flat light or white out conditions routinely occur to include safe practices for operating in flat light or white out conditions in their approved training programs.

Safety Recommendation A-02-35 (closed – acceptable action as of September 11, 2014) states;

Require the installation of radar altimeters in all helicopters conducting commercial, passenger-carrying operations in areas where flat light or white out conditions routinely occur.

Alaska Flight Operations

The NTSB has published Safety Study 95/03 Aviation Safety in Alaska (1995). This safety study identifies various safety issues unique to flight operations in Alaska. The findings section of this study states in part;

Pilots and commercial aviation operators in Alaska continue to conduct flights with higher-than-normal risks, in response to demands for reliable air service in an operating environment and aviation infrastructure that are often inconsistent with these demands.

The continued occurrence of accidents involving flight under visual flight rules into instrument meteorological conditions in Alaska's commuter airline and air taxi industries highlights the need to provide flight crews, during initial and recurrent stages of the operators' training programs, aeronautical decision making training that is tailored to commercial operations and Alaska's aviation environment.

Flat Light and White Out Conditions

The FAA has published a pamphlet, Flying in Flat Light and White Out Conditions (2001). This pamphlet describes techniques for safe flight operations in flat light and white out conditions. This pamphlet provides various definitions and states in part;

Flat Light: Flat light is an optical illusion, also known as "sector or partial white out." It is not as severe as "white out" but the condition causes pilots to lose their depth-of-field and contrast in vision. Flat light conditions are usually accompanied by overcast skies inhibiting any good visual clues. Such conditions can occur anywhere in the world, primarily in snow covered areas but can occur in dust, sand, mud flats, or on glassy water. Flat light can completely obscure features of the terrain, creating an inability to distinguish distances and closure rates. As a result of this reflected light, it can give pilots the illusion of ascending or descending when actually flying level. However, with good judgment and proper training and planning, it is possible to safely operate an aircraft in flat light conditions.

White Out: As defined in meteorological terms, white out is when a person becomes engulfed in a uniformly white glow. The glow is a result of being surrounded by blowing snow, dust, sand, mud or water. There are no shadows, no horizon or clouds and all depth-of-field and orientation are lost. A white out situation is severe in that there aren't any visual references. Flying is not recommended in any white out situation. Flat light conditions can lead to a white out environment quite rapidly, and both atmospheric conditions are insidious: they sneak up on you as your visual references slowly begin to disappear. White out has been the cause of several aviation accidents in snow-covered areas.

Self-Induced White Out: This effect typically occurs when a helicopter takes off or lands on a snow-covered area. The rotor down wash picks up particles and re-circulates them through the rotor system. The effect can vary in intensity depending upon the amount of light on the surface. This phenomenon can happen on the sunniest, brightest day with good contrast everywhere. However, when it happens, there can be a complete loss of visual clues. If the pilot has not prepared for this immediate loss of visibility, the results can be disastrous.

This pamphlet states that when a pilot loses all visual references to;

Trust the cockpit instruments.

Execute a 180-degree turn around and start looking for outside references.

Above all, fly the aircraft.

This pamphlet states to lower flat light risks;

Always leave yourself an out.

Don't fly until you only have one visual reference left.

Try not to lose sight of your reference point at any time. Plan your approach so that your reference is always on your side when flying. Never turn away from your reference point.

Fly with your head straight, looking forward; believe what your flight instruments are showing you.

In summary, this pamphlet states;

There are many factors that come into play when dealing with flat light and white out conditions. A pilot's instinctive responses must be immediate, and based on a well thought out plan. These unique visual conditions are insidious and can sneak upon you at any time. The environment can present challenging obstacles making the flight even more difficult. Completing a safe flight may mean choosing an alternate landing site, returning to the point of departure or simply choosing not to fly.

Pilots should establish individual personal minimums, setting strict parameters for landings and sticking by them. Continuing education especially with regard to instrument proficiency, talking to local flight operators, and gaining insight into the psychological, aeromedical, and physiological effects of flight are essential in keeping up with these unique atmospheric phenomena.

Spatial Disorientation

The U.S. Army has published Training Circular 3-04.93 Aeromedical Training for Flight Personnel (2009). This training circular describes what spatial disorientation is, the three types, the prevention, and the treatment. This training circular states in part;

Spatial Disorientation (SD) is an individual's inability to determine his or her position, attitude, and motion relative to the Earth's surface. When SD occurs, pilots are unable to see, believe, interpret, or prove information derived from their flight instruments. They instead rely on false information provided by their senses.

In type I SD (unrecognized), an aviator does not perceive any indication of SD or think anything is wrong. What the aviator sees—or thinks he or she sees—is corroborated by other senses. The pilot might see the instruments functioning properly and have no suspicion of instrument malfunction. Likewise, the aircraft might be performing normally with no indication of aircraft control malfunction. Unaware of a problem, the pilot fails to recognize or correct the SD, a mistake that usually results in a fatal aircraft mishap. Type I SD is the most dangerous type of disorientation. An example is the height/depth perception illusion, where a pilot descends into the ground or some obstacle above the ground due to a lack of situational awareness.

In type II SD (recognized), the pilot perceives a problem resulting from SD but might not recognize it as SD. The pilot might feel a control is malfunctioning or perceive an instrument failure as in the graveyard spiral, a classic example of type II SD. The pilot will not correct aircraft roll as indicated by the attitude indicator because his or her vestibular indications of straight-and-level flight are so strong.

In type III SD (incapacitating), the pilot experiences such an overwhelming sensation of movement that he or she cannot orient using visual cues or the aircraft instruments. Type III SD is not fatal if the copilot can gain control of the aircraft.

SD cannot be eliminated, but crewmembers must remember the misleading sensations from sensory systems are predictable. Due to normal functioning and limitations of the senses, all pilots, regardless of experience level, can suffer the effects of SD. As such, crewmembers must be aware of SD's potential hazards, understand their significance, and learn to overcome them. Training, instrument proficiency, good health, maintaining situational awareness, and aircraft design all help to minimize SD. Additional measures pilots should take to prevent SD include—

Never fly without visual reference points (either the actual horizon or artificial horizon provided by the instruments).

Trust the instruments. Pilots must never try to fly visual meteorological conditions and instrument meteorological conditions at the same time.

Avoid fatigue, smoking, hypoglycemia, hypoxia, and anxiety, all of which intensify illusions.

SD can easily occur in the aviation environment. If SD occurs, pilots should—

Refer to the instruments and develop a good cross-check.

Delay intuitive actions long enough to check both visual references and the instruments.

Transfer control to the other pilot (if two pilots are in the aircraft); rarely will both pilots experience SD at the same time.

NTSB 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.