Canada’s TSB calls for helicopter safety improvements on intermittent IMC

An investigation from Canada’s Transportation Safety Board (TSB) found insufficient regulatory requirements and defenses against visual reference accidents led to the fatal crash of an Airbus H125 helicopter on Griffith Island, Nunavut. 

The crash killed all three people on board — the pilot, an aircraft maintenance engineer, and a biologist — and was operated by Great Slave Helicopters 2018 Ltd. It was returning to Resolute Bay, Nunavut, on April 25, 2021, when it collided with terrain, investigators said. 

A TSB investigation found the aircraft entered inadvertent flight into instrument meteorological conditions (inadvertent IMC) and snow squalls likely created flat light and whiteout conditions during the flight.  

“While the pilot was likely attempting to visually maneuver the helicopter in response to inadvertent flight into IMC, an unintentional descent resulted in the helicopter colliding with terrain,” investigators said. 

“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.’’  

In Canada, there are no regulatory requirements for commercial helicopter operators to ensure pilots are adequately trained and have the technology needed to recover from inadvertent flight into IMC, the TSB found. Single-pilot operators are also not required to have standard operating procedures with pre-determined solutions for situations including inadvertent 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,” investigators said.  

“These differences permit helicopters to operate at half the visibility applicable to airplanes, but without the same level of defences.” 

As a result of its research, the TSB made the following recommendations to Transport Canada:  

1. Require commercial helicopter operators to ensure pilots possess the skills necessary to recover from inadvertent flight into IMC.  

2. Require commercial helicopter operators to implement technology that will assist pilots with the avoidance of, and recovery from, inadvertent flight into IMC. 

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. 

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.  

Investigators said Great Slave Helicopters implemented numerous safety actions following the incident, including amending its 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,” investigators said.  

“The TSB has identified loss of spatial awareness in 13 investigations involving commercial helicopter flights conducted between 2010 and 2018.”