Safety communications related to TSB investigation A21C0038: April 2021 collision with terrain on Griffith Island, Nunavut

The occurrence

Late afternoon on 25 April 2021, the Great Slave Helicopters 2018 Ltd. Airbus Helicopters AS350 B2 (A21C0038) departed from a remote camp on Russell Island, Nunavut (NU), on a day visual flight rules (VFR) flight to Resolute Bay Airport, NU. On board were the pilot, an aircraft maintenance engineer, and a biologist. The purpose of the flight was to return to Resolute Bay following 12 days spent conducting polar bear research for a client, given that poor weather was forecast in the area for the next several days.

As the helicopter approached the highest elevation of Griffith Island, it was met with a combination of snow-covered terrain, overcast sky, and falling snow which created flat light and whiteout conditions. This led to an unexpected loss of visual reference, also known as inadvertent instrument meteorological conditions. The attempt to visually manoeuvre the helicopter in response to the whiteout conditions resulted in an unintentional descent and subsequent collision with terrain. There were no survivors.

Safety communications

Recovery from inadvertent flight into instrument meteorological conditions

Despite the prevalence of loss of visual reference accidents involving visual flight rules (VFR) helicopter operations, and even though some VFR helicopter pilots are authorized to fly in visibility as low as ½ statute mile, there is no requirement for Canadian commercial helicopter operators to ensure that company pilots possess the skills necessary to recover from inadvertent flight into instrument meteorological conditions (IIMC).

During this investigation, the TSB discovered that some Canadian commercial helicopter operators with pilots who possess instrument flight rules (IFR) flight experience place considerable importance on equipping their aircraft and training their VFR pilots for IIMC recovery when operating above the tree line during the winter months. However, other companies that only conduct VFR operations, including Great Slave Helicopters 2018 Ltd. (GSH), have adopted and rely on an “avoid-at-all-costs” approach to IIMC. This approach, which is permitted under the Canadian Aviation Regulations (CARs), relies on a pilot’s ability to avoid IIMC and to fly solely by reference to outside visual cues.

As seen in this occurrence, and many others highlighted in this report,^{Footnote 1} it may be ineffective to rely on an approach predicated on intentionally avoiding something that is unintended. Given the number of IIMC accidents that have occurred, and that helicopter accidents are more than twice as likely to involve a loss of visual reference than are airplane accidents, it is apparent that the “avoid-at-all-costs” approach to IIMC is not effective when used in isolation. The reliance on this approach can place pilots and passengers at increased risk of IIMC accidents because that approach typically encourages pilots to fly lower and slower as the weather deteriorates until they determine it is no longer safe to do so. This approach typically puts helicopters at close proximity to the ground in a flight profile that could make it harder, if not impossible, to transition to flight instruments if visual references are lost.

When the occurrence pilot recognized the need to take evasive action, he lacked the skills necessary to safely transition to instrument flight and carry out a pre-determined IIMC recovery procedure, such as climbing straight ahead or conducting a 180° turn to return to visual meteorological conditions, before all external references were lost. Instead, the occurrence pilot most likely relied on the technique he was trained to use, which was to continue flying by reference to outside references, until inadequate visual cues existed. This technique resulted in the occurrence helicopter inadvertently impacting the terrain when the pilot likely encountered IMC due to flat light and whiteout conditions.

Following a series of flat light and whiteout condition accidents involving  commercial VFR helicopters in the United States (U.S.), the U.S. National Transportation Safety Board issued several safety recommendations in 2002 aimed at reducing these types of occurrences. As a result of these recommendations, the U.S. Federal Aviation Administration made changes to the Federal Aviation Regulations. One of the most notable changes was an initial and recurrent requirement for commercial helicopter pilots to demonstrate that they possess the skills necessary to recover from an IIMC encounter.^{Footnote 2} The Helicopter Association International has also recognized the need for action and has developed a comprehensive approach to IIMC that includes training on both avoidance of, and recovery from, IIMC situations. This approach is endorsed by the United States Helicopter Safety Team and the Helicopter Association of Canada.

In Canada, the flight test to obtain the private and then the commercial helicopter licence requires that pilots demonstrate several skills such as hovering, steep turns, and autorotations. Additionally, a pilot must demonstrate the ability to maintain control by reference to flight instruments during simulated IIMC.^{Footnote 3} This shows that helicopter pilots with limited instrument flying experience can be trained to carry out an IIMC recovery procedure solely by reference to flight instruments.

Once pilots obtain their commercial licence, several of these flight test requirements (e.g., autorotations) must be demonstrated during annual pilot proficiency checks. However, despite the number of helicopter IIMC accidents and associated fatalities, there is no requirement for commercial VFR helicopter pilots to demonstrate during pilot proficiency checks that they retain the skills necessary to recover from IIMC. Since there is no requirement to maintain this skill set, there is no requirement for commercial VFR helicopter operators to provide their pilots with IIMC recovery training. Without recurrent training, either in the aircraft or through other means, skill erosion will occur. The more time that has elapsed since pilots were last tested on the ability to recover from IIMC, the less likely they will have both the skill and confidence to carry out such a manoeuvre under real-life conditions.^{Footnote 4},^{Footnote 5} Therefore, the current regulations allow VFR helicopter pilots to operate in environmental conditions conducive to a loss of visual references, without any assurances that they possess the skills necessary to recover from an IIMC encounter.

In 1990, the TSB issued Recommendation A90-81 calling for TC to require verification of proficiency in basic instrument flying skills for commercially employed helicopter pilots during annual pilot proficiency flight checks. After a lack of action by TC over several years, the Board considered TC’s response to this recommendation to be Unsatisfactory and changed the recommendation status to dormant.^{Footnote 6}

Because there is no requirement for commercial helicopter operators to ensure that pilots possess the skills necessary to recover from IIMC, the pilots and passengers who travel on VFR helicopters are at increased risk of collision with terrain following a loss of visual references.

Therefore, the Board recommends that

Technology as a defence against inadvertent flight into instrument meteorological conditions accidents

A robust approach to preventing accidents resulting from a loss of visual references must include multiple defences that will assist in the avoidance of, and recovery from, IIMC. This is particularly true for commercial VFR helicopters, which routinely operate at lower altitudes than commercial VFR airplanes. Recommendation A24-01 identifies the need for pilots to possess the skills necessary to recover from IIMC. However, equally important is the need for pilots to be provided with information that will help maximize situational awareness and support pilot decision making (PDM) before or after entering IIMC. There are several ways that technology can be used to prevent IIMC accidents.

In this occurrence, the pilot encountered flat light and whiteout conditions as the helicopter crossed Griffith Island. The helicopter was equipped with flight instruments; however, the pilot relied on the “avoid-at-all-costs” approach to these conditions, which is permitted under the CARs and was part of his training. Thus, the pilot was trained to fly solely on outside visual references in situations of reduced visibility. Additionally, the occurrence helicopter was not equipped with technology capable of alerting the pilot to the helicopter’s height above ground or rate of descent. Therefore, the pilot had no way of being warned of the impending collision with terrain that occurred shortly after he likely attempted a visual 180° turn in instrument meteorological conditions.

One of the most basic examples of technology that can help prevent IIMC accidents is flight instrumentation. The CARs outline specific flight instrumentation requirements for aircraft operated under IFR;^{Footnote 7} however, the requirements are significantly lower for aircraft operated under VFR.^{Footnote 8} Specifically, VFR aircraft are not required to be equipped with flight instruments that are critical to aircraft control in conditions such as flat light and whiteout conditions, which have been repeatedly associated with IIMC accidents,^{Footnote 9} just like in this occurrence.

In 1990, the TSB issued Recommendation A90-84 calling on TC to require all commercially-operated helicopters to be equipped with appropriate instrumentation for the conduct of basic instrument flying. TC does not support this active recommendation. Therefore, given the lack of progress, the Board considers TC’s response to Recommendation A90-84 as unsatisfactory.

During the investigation into this occurrence, the TSB discovered that some Canadian commercial helicopter operators with management staff who possess IFR flight experience consider it essential that VFR helicopters operating above the tree line during the winter months be equipped with flight instruments necessary for IFR, and pilots be trained for IIMC recovery. Some of those operators also consider it vital to equip those aircraft with radar altimeters, and one operator has begun using synthetic vision systems. In contrast, some VFR helicopter operators do not see a need to implement these defences. In the case of GSH, the company’s management pilots, who were VFR-only rated pilots, did not feel it was necessary to implement similar defences, even though some pilots had requested it. GSH’s management pilots were also aware that, in 2015, the company’s predecessor had an accident in flat light and whiteout conditions that resulted in several internal recommendations. . However, the absence of formal requirements to equip VFR helicopters with basic flight instruments has likely contributed to a perception among some VFR helicopter operators that the use of basic flight instruments, and the training needed to use them, will not necessarily prevent IIMC accidents. As a result, VFR helicopter pilots continue to be dispatched to areas prone to environmental conditions such as flat light and whiteout without basic flight instrumentation and without training on how to use that instrumentation if all visual references are lost. This places VFR helicopter pilots and the passengers who fly on those aircraft at increased risk of collision with terrain following an IIMC encounter.

In addition to basic flight instrumentation, several technological advances have emerged to enhance pilot situational awareness and, therefore, assist in the reduction of IIMC accidents. Many of these systems can alert pilots to unintended flight profile changes that increase the risk of an IIMC accident. For example, some systems can be used to establish “en-route decision triggers,” such as a minimum height above ground, and alert the pilot if the helicopter’s height above ground drops below the preset threshold. This can be particularly beneficial in conditions of flat light and whiteout because of their insidious nature, which can make it difficult for a pilot to accurately assess height above ground.

More advanced forms of technology, such as helicopter terrain awareness and warning systems, can also warn of an impending collision with terrain or of excessive rates of descent close to the ground. These types of alerts can help a pilot recognize, in a timely manner, that emergency action must be taken to prevent a collision with terrain. Another form of technology that has become more widespread in recent years is synthetic vision systems, which are capable of providing pilots with a virtual 3-dimensional map on a display in the cockpit, or in a tablet-based application such as ForeFlight. This same application can, with some minor aircraft modifications, provide the pilot with a set of backup flight instruments like a modern glass cockpit.

The above-mentioned forms of technology help maximize pilot situational awareness by providing the pilot with information that may not otherwise be available if solely relying on outside visual references. With proper training and procedures, these technologies can greatly reduce the risk of IIMC accidents by warning the pilot when safety margins are being eroded or by assisting the pilot to escape IIMC.

In 2002, following a series of accidents involving VFR helicopters in flat light, the U.S. National Transportation Safety Board issued a safety recommendation calling for the installation of radar altimeters in commercial helicopters operating in areas where flat light or whiteout conditions routinely occur.^{Footnote 10} After several additional accidents involving these conditions, the U.S. Federal Aviation Administration chose to expand the scope of this recommendation and amended the Federal Aviation Regulations to require all commercial helicopters be equipped with a radar altimeter or a device that incorporates a radio altimeter. According to the Federal Aviation Administration, “radio altimeters help increase situational awareness during inadvertent flight into instrument meteorological conditions (IIMC), night operations, and flat-light, whiteout, and brownout conditions.”^{Footnote 11}

In 1990, the TSB issued Recommendation A90-83 calling on TC to require all helicopters engaged in commercial passenger carrying operations be equipped with radar altimeters. TC did not support this recommendation. In September 2012, given the lack of progress addressing the safety deficiency associated with Recommendation A90-83, the Board considered TC’s response to be Unsatisfactory and changed the recommendation status to dormant.

The TSB has previously attempted to address safety issues related to helicopter collision with terrain accidents, calling for increased requirements for flight instrumentation and other systems such as radar altimeters. To date, TC has not taken the measures needed to address these recommendations, which were issued more than 30 years ago. The Board believes that more must be done to reduce the incidence of loss of visual reference accidents, which are more than twice as likely to involve a helicopter than they are to involve an airplane. Many forms of technology now exist that, if required by regulation, could greatly reduce the risk of IIMC accidents, particularly in areas prone to flat light and whiteout conditions. Because there is no requirement for VFR helicopters to be equipped with technology that can assist pilots with the avoidance of, and recovery from, IIMC, the pilots and passengers who fly on those helicopters remain at increased risk of collision with terrain.

Therefore, the Board recommends that

Standard operating procedures for single-pilot commercial operations

In this occurrence, the VFR helicopter pilot, who had limited training and experience operating “in the white,” attempted to cross Griffith Island in flat light and whiteout conditions that were likely created by the uniformly snow-covered and featureless terrain,  an overcast sky, and snow squalls. By doing this, the pilot inadvertently flew the helicopter into instrument meteorological conditions. The urgency of the situation, combined with the pilot’s lack of experience in similar conditions, likely caused a rapid increase in mental workload as the pilot tried to analyze an unfamiliar situation and select an appropriate course of action. It is likely that while the pilot attempted to visually manoeuvre the helicopter in response to the reduced visual cues, in accordance with his reduced-visibility training, an unintentional descent resulted, and the helicopter impacted the terrain on a near-reciprocal track to the intended route.

There are several ways to mitigate risk when a pilot lacks experience in a specific operational setting. Ideally, multiple defences should be implemented to reduce risk as low as reasonably practicable. For example, operationally realistic training can help prepare a pilot for situations that may be encountered during operational taskings. Another way of mitigating the risk is to increase the level of supervision. During remote operations, this might include implementing enhanced communication protocols, such as mandatory check-ins, to support PDM. Another risk mitigation strategy, which is required by regulation for multi-crew flight operations, is to develop standard operating procedures (SOPs) for company pilots. As identified by the investigation into this occurrence, single-pilot operations conducted under subparts 604, 702, 703, and 704 of the CARs are permitted without SOPs.

SOPs are widely accepted as a tool to enhance safety in multi-crew operations^{Footnote 12} and many of their benefits apply equally to single-pilot operations. SOPs assist PDM by providing pilots with pre-determined successful solutions, based on corporate knowledge and industry best practices, for specific situations that may be encountered. SOPs are particularly beneficial when a pilot lacks the knowledge or experience in a situation, and a less-than-ideal course of action could reduce safety margins. In those instances, SOPs can help reduce pilot workload, given that less mental effort is required to work through the decision-making process because that process has already been done for the pilot. The current regulatory requirements likely contribute to a perception that SOPs are more important in multi-crew than single-pilot operations. As a result, SOPs are less common, and typically less structured, in single-pilot operations than in multi-crew operations.

The TSB has investigated multiple occurrences involving single-pilot operations where SOPs were either absent because they were not required by regulation, or they were inadequate.^{Footnote 13} To realize the full benefits of SOPs, the regulations should be amended to require SOPs for all single-pilot operations conducted under Subpart 604 (private) and Part VII (commercial) of the CARs.

From 2001 to 2003, TC issued several notices of proposed amendments (NPAs) intended to expand the requirement for SOPs to “all operated flights regardless of the number of crew or complexity of the aircraft.”^{Footnote 14} More than 20 years after these NPAs were issued, they remain in various stages of review (Table 1).

*Civil Aviation Regulation Advisory Council

Some companies that engage in single-pilot operations, such as GSH, have voluntarily developed task-specific SOPs. In the absence of formal requirements and clear guidance to assist single-pilot operators with SOP development, these operators may not fully understand how to design effective procedures. For example, GSH had a task-specific SOP for operations above the tree line; however, that SOP consisted mainly of high-level guidance rather than safe flying practices such as establishing en-route decision triggers like minimum height above ground or minimum airspeed. In addition, the SOPs did not include the operational practice, employed by senior pilots at GSH and echoed by the Polar Continental Shelf Program personnel, of avoiding overflying a barren snow-covered island. As a result, this corporate knowledge was not available to the occurrence pilot who had limited experience in that operating environment.

In Canada, thousands of pilots and passengers travel on single-pilot aircraft every year. In many instances, those flights are conducted in remote areas, with minimal external support. In these environments, additional defences must be put in place to support PDM to ensure safety margins are maintained. SOPs allow for easy sharing of corporate knowledge and best practices, and they help ensure consistency among pilots. Because there is no requirement for CARs Subpart 604 and Part VII single-pilot operations to have SOPs, pilots and passengers who travel on those aircraft are at increased risk of accident resulting from ineffective decision making and from cognitive workload in response to novel or unexpected situations.

Therefore, the Board recommends that

Enhanced risk mitigation for reduced-visibility operations in uncontrolled airspace

In Canada, many VFR helicopter and airplane operators are approved by TC to conduct reduced-visibility operations in uncontrolled airspace. The approval, granted as an operations specification, outlines requirements that operators must meet to carry out reduced-visibility operations in uncontrolled airspace. Some of these requirements are the same for helicopters and airplanes; however, there are also some notable differences when considering visibility limit, aircraft equipment, and pilot training (Table 2).

These differences mean that helicopters may be operated at half the visibility applicable to airplanes, without the added benefits of the defences required for airplane operations to recover from a loss of visual references. This is likely contributing to a perception identified during this investigation whereby some VFR helicopter operators believe that instrument flight training and basic instrumentation are not needed by VFR helicopter pilots. As a result, some VFR helicopter operators have adopted an “avoid-at-all costs” approach to IIMC accidents, that does not consider the possibility that a pilot may need to recover from an IIMC encounter.

This may partially explain why TSB statistics show that helicopter accidents are more than twice as likely to involve a loss of visual reference than are airplane accidents.^{Footnote 15} The current regulations authorize VFR helicopter pilots to operate in flight visibilities as low as ½ SM without instrument flight training or basic instruments. This flight regime leaves little margin for error and time to react if there is a further reduction in visibility.

The Board believes that additional defences must be implemented for those VFR helicopter operations that are approved to operate in reduced visibilities, where the risk of an IIMC accident is even greater because of the reduced safety margins associated with operating at lower visibilities and, typically, lower altitudes. To offset the increased risk, the operations specification for airplanes includes defences specifically intended to assist a pilot in the recovery from IIMC. However, helicopter pilots approved for reduced-visibility operations in uncontrolled airspace are permitted to operate in lower visibility than airplanes and yet are expected to rely solely on their ability to avoid IIMC. This means that helicopter pilots may be unprepared should their attempts at avoiding IMC prove ineffective.

If regulations continue to allow commercial helicopter operators with the applicable operations specification to conduct reduced-visibility operations in uncontrolled airspace at lower visibility, and with significantly fewer defences, than commercial airplane operators, these helicopter operators will continue to be at a greater risk of collision as a result of lost visual references.

Therefore, the Board recommends that