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News release

Associated links (A21C0038)

TSB raising the bar on safety: Reducing the risks that persist in commercial helicopter operations

Gatineau, Quebec, 15 February 2024 — In its investigation report (A21C0038) released today, the Transportation Safety Board of Canada (TSB) found that insufficient regulatory requirements and defences to protect against loss of visual reference accidents led to the fatal 2021 crash of an Airbus AS350 helicopter on Griffith Island, Nunavut (NU). As such, the Board is issuing four recommendations to the regulator, Transport Canada.

On 25 April 2021, the helicopter, operated by Great Slave Helicopters 2018 Ltd., was returning to Resolute Bay, NU, when it collided with terrain killing all three on board – the pilot, an aircraft maintenance engineer, and a biologist.

The investigation found that as the helicopter approached the highest elevation on Griffith Island, the uniformly snow-covered and featureless terrain, an overcast sky, and snow squalls likely created flat light and whiteout conditions. This led to an unexpected loss of visual reference to the horizon, also known as inadvertent flight into instrument meteorological conditions (inadvertent IMC). While the pilot was likely attempting to visually manoeuvre the helicopter in response to inadvertent flight into IMC, an unintentional descent resulted in the helicopter colliding with terrain.

“For more than 30 years, the TSB has been calling for the implementation of safety measures to mitigate the risks that persist in helicopter reduced visibility operations.’’ said Kathy Fox, TSB Chair. “These are systemic safety issues that continue to put at risk the lives of thousands of pilots and passengers every year.’’

The investigation determined that currently there are no regulatory requirements for commercial helicopter operators to ensure that pilots have the training and technology required to be able to recover from an inadvertent flight into IMC. Additionally, single-pilot operators (either helicopter or airplanes) are not required to have standard operating procedures, which would provide pilots with pre-determined successful solutions for specific situations that may be encountered, including an inadvertent flight into IMC.

TSB research has found that although “loss of visual reference” accidents are more than twice as likely to involve helicopters than airplanes, requirements for helicopters are less stringent. These differences permit helicopters to operate at half the visibility applicable to airplanes, but without the same level of defences. 

This is why the Board is issuing the following four recommendations calling on Transport Canada to:

  1. require commercial helicopter operators to ensure pilots possess the skills necessary to recover from inadvertent flight into IMC. [A24-01]
  2. require commercial helicopter operators to implement technology that will assist pilots with the avoidance of, and recovery from, inadvertent flight into IMC. [A24-02]
  3. require private and commercial operators conducting single-pilot operations to develop standard operating procedures based on corporate knowledge and industry best practices to support pilot decision-making. [A24-03]
  4. enhance the requirements for helicopter operators that conduct reduced-visibility operations in uncontrolled airspace to ensure that pilots have an acceptable level of protection against inadvertent flight into IMC accidents. [A24-04]

Following the accident, Great Slave Helicopters 2018 Ltd. implemented numerous safety actions, including: amending standard operating procedures, revising and updating pilot training, implementing new procedures, and establishing quarterly safety management meetings.

The risks associated with the loss of visual references due to flat light and/or whiteout conditions are not new. The TSB has identified loss of spatial awareness in 13 investigations involving commercial helicopter flights conducted between 2010 and 2018 and has issued 10 recommendations to Transport Canada aimed at preventing inadvertent IMC accidents.

For more information about this investigation visit:

The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

For more information, contact:
Transportation Safety Board of Canada
Media Relations
Telephone: 819-360-4376