TSB releases investigation report about a 2020 landing accident in Calgary, Alberta

Edmonton, Alberta, 12 May 2021 — In its investigation report (A20W0016) released today, the Transportation Safety Board of Canada (TSB) found that a flap malfunction combined with the flight crew’s handling of the “flaps fail landing procedure” led to a loss of aircraft pitch control and subsequent contact of the rear fuselage with the runway while landing in Calgary, Alberta.

Rear fuselage damage (Source: Canadian Pacific Railway Company)

On 23 February 2020, a Bombardier Challenger 605 operated by the Canadian Pacific Railway Company (CP) departed Palm Beach International Airport, Florida, United States, for Calgary International Airport, Alberta, with three crew members and 10 passengers on board. During the descent, the flight crew attempted to deploy the flaps and immediately received a “FLAPS FAIL” caution message. The flight crew proceeded to complete the flap failure procedure from the Quick Reference Handbook (QRH).

The investigation found that after the nose wheel touched the ground during the landing, maximum reverse thrust was selected; however, insufficient pressure was applied to the control column to maintain the nose landing gear on the runway. As a result, the nose pitched up, and the rear fuselage contacted the runway. The aircraft’s stall protection system then commanded a rapid nose-down control input, leading to damage to the forward section of the aircraft when the nose wheel contacted the runway. Once the landing was completed, the aircraft continued to the intended parking area. There were no injuries to any of the aircraft occupants, although there was significant damage to the aircraft.

Occurrence aircraft’s failed flap flexible drive shaft (Source: Canadian Pacific Railway Company)

The flap failure occurred when one of the flap flexible drive shafts failed. Moisture entered the flap flexible drive shaft casing, likely through the undetected puncture holes and the drive shaft casing to flap actuator interface, which led to the subsequent corrosion and failure of the inner drive shaft. As the aircraft’s actual annual utilization was approximately half of that expected by the manufacturer, the calendar time interval between maintenance inspections increased. As a result, the corrosion that developed was not detected because the shaft had not yet reached the 2400 flight-hour maintenance interval.

The pilot monitoring did not read the cautions included on the flaps fail checklist out loud to the pilot flying during the completion of the QRH procedure. As a result, information critical to the safe operation of the aircraft was not brought to the pilot flying’s attention.

It was also found that the Challenger 605 flight simulator used for recurrent training did not accurately represent the zero-flap handling characteristics of the aircraft when the thrust reversers are deployed, nor was it required for certification. As a result, the flight crew was inadequately prepared to prevent, or recover from, the nose pitch-up that occurred when the thrust reversers were deployed.

Following the occurrence, CP amended its procedures to address the differences between the caution and warning notes published in the Aircraft Flight Manual and QRH. Bombardier issued a temporary revision to the QRH flap fail procedure. The TSB issued an Air Safety Information Letter (A20W0016-D1-L1) to highlight the Challenger 605 series flap system inspection interval, and a CL60 series cross-fleet product improvement observation.

See the investigation page for more information.

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.

Unstable approach led to 2020 hard landing and rear fuselage strike in Schefferville, Quebec

Dorval, Quebec, 3 March 2021 — In its investigation report (A20Q0013) released today, the Transportation Safety Board of Canada (TSB) found that the January 2020 hard landing and rear fuselage strike in Schefferville, Quebec, was the result of an unstable approach.

From Air Inuit

On 20 January 2020, a de Havilland DHC-8-314 operated by Air Inuit Ltd. was conducting a flight from Québec/Jean Lesage Airport, Quebec, to Schefferville Airport, Quebec, with three crew members and 42 passengers on board. During the landing, the rear fuselage struck the runway as the wheels touched down. After landing, the aircraft taxied to the terminal to disembark the passengers. There were no injuries; however, the aircraft sustained substantial damage.

The investigation found that the flight crew forgot to perform the descent checklist and realized this at an inopportune time, while the captain (pilot monitoring) was providing a position report. Given ambiguities and contradictions in the company’s stabilized approach guidelines, the captain interpreted that he was allowed to continue the approach below 500 feet above aerodrome elevation, even though the aircraft had not been fully configured for the landing. When the aircraft passed this altitude, the pilots, who were dealing with a heavy workload, didn’t notice and continued the approach, which was unstable. At the time of the landing, the aircraft no longer had enough energy to arrest the descent rate solely by increasing pitch attitude. The pilot’s instinctive reaction to increase the pitch attitude during the flare, combined with the hard landing, resulted in the rear fuselage striking the runway, causing substantial damage to the aircraft’s structure.

The investigation also made findings as to risk related to Air Inuit’s standard operating procedures (SOPs) and training, and to Transport Canada’s (TC) oversight. Transport Canada assessed Air Inuit’s SOPs, but did not identify any specific issues with the operator’s stabilized approach guidelines. If TC does not assess the quality, consistency, accuracy conciseness, clarity, relevance, and content of SOPs, the procedures may be ineffective, increasing risks to flight operations.

Additionally, the captain had not received many of the required training elements during his recurrent training. If required training elements are not included in recurrent training, and if TC’s surveillance plan does not verify the content of crew training, there may be procedural deficiencies or deviations, increasing risks to flight operations.  

Following the occurrence, Air Inuit took a number of safety actions, including the revision of its SOPs to improve guidelines on several subjects, including stabilized approaches, and the revision of its training program to ensure that all training elements are covered within the two-year recurrent training cycle.

See the investigation page for more information.

Inaccurate Airborne Status Transmitted by Transponders and its Effect on Runway Monitoring and Conflict Alert Systems – Civil Aviation Safety Alert

Transport Canada


The purpose of this Civil Aviation Safety Alert (CASA) is to raise awareness to aircraft owners, operators and Air Navigation Services Providers (ANSP) on an issue related to operation of aircraft equipped with the Honeywell Primus Epic integrated avionics system transponders.


The Transportation Safety Board (TSB) recently advised Transport Canada of an occurrence at Toronto/Lester B. Pearson International Airport (CYYZ) where immediately following a rejected takeoff, an Embraer 190 (E190) equipped with a Honeywell Primus Epic integrated avionics system transponder incorrectly transmitted that the aircraft was in airborne status but remained on the runway.

A second aircraft, a Boeing 777-300 (B777) readying for take-off had been issued a take-off clearance while the E190 remained on the runway. Although the E190 flight crew made a radio call to the tower that they were aborting the takeoff, at the same time the B777 read back its take-off clearance on the same control tower frequency and commenced its take-off roll. The simultaneous radio transmissions went undetected and neither air traffic control nor the B777 flight crew heard the abort radio call of the E190.

Immediately after beginning its take-off roll the B777 flight crew observed that the E190 was still on the runway and initiated a rejected takeoff. The B777 came to within 3800 feet from the E190.

In the initial assessment in its investigation (TSB investigation A20O0029) the TSB has found that the Honeywell Primus Epic integrated avionics system in the E190 uses software logic that determines the aircraft to be airborne when the aircraft’s indicated airspeed exceeds 50 knots. The result being that the aircraft transponder may transmit that the aircraft is airborne when the aircraft may still be on the ground.

Additionally, the runway incursion monitoring and conflict alert system (RIMCAS) used by the air navigation service provider (ANSP) at CYYZ was configured to use data from the aircraft’s transponder transmission as the primary indication that an aircraft had become airborne. Therefore when the E190 exceeded 50 knots on its departure roll, the RIMCAS identified the aircraft as airborne even though it was not. As a result of this system logic, the RIMCAS did not detect a conflict when the B777 began its take-off roll, and did not issue an alert until well after both aircraft had initiated their respective rejected-takeoff procedures and decelerated.

In December 2020, NAV CANADA published an Urgent ATC Information Bulletin for all Toronto Tower personnel. The bulletin cautioned controllers that RIMCAS Stage 1 and Stage 2 alerts may not be generated when Embraer E-jets and some aircraft manufactured by Dassault, Gulfstream, Learjet, and Textron Aviation (formerly Cessna) are departing. The bulletin also advised that Stage 1 and Stage 2 alerts may not be produced for aircraft or vehicles approaching the active runway when one of these aircraft types is departing, and controllers were reminded to monitor these situations closely. NAV CANADA is investigating options for RIMCAS software mitigations.

Transport Canada is in the process of communicating with the original equipment manufacturer (OEM) to address the current software logic to identify aircraft airborne status. Additionally, Transport Canada is in the process of communicating with applicable ANSP who have similar RIMCAS that could yield a comparable outcome with aircraft with similarly configured transponders.

Recommended action

  1. Air operators currently operating aircraft equipped with Honeywell Primus Epic integrated avionics system should provide the information found in this CASA to staff and/or flight crew as a means of awareness.

Helicopter pilot killed in Nunavut crash was adventurous, lovable, remembers partner

From CBC News – link to source story

‘He was the most wonderful human I’ve met in my whole life’

Liny Lamberink · CBC News · May 01, 2021

Steven Page, 36, was one of three men who died after a helicopter belonging to Great Slave Helicopters went down outside of Resolute Bay, Nunavut. (Submitted by Sandra Soares)

A 36-year-old helicopter pilot, killed in last week’s crash in Nunavut, is being remembered as the kind of guy everyone would fall in love with. 

Steven Page was one of three men who died last Sunday, when the AS350-B3 aircraft they were travelling in crashed 22 kilometres southwest of Resolute Bay.

His partner, Sandra Soares, told CBC News she got the first phone call from Yellowknife-based Great Slave Helicopters that evening — alerting her that something had gone wrong.

“His boss, John, called me around 7:30 on Sunday and said Steve missed his check-in and they weren’t sure what was going on,” she said. “[I was] stirring and pacing and feeling pretty sick, but in the back of mind thinking, ‘Well, Steve’s always OK.'” 

Less than five hours later, she would find out that he wasn’t.

Sandra Soares, right, snapped this photo with Page on their first date together, when they bushwhacked up Grey Mountain outside of Whitehorse in search of a cave. (Submitted by Sandra Soares)

“I got the call around midnight that they found the crash site and there were no survivors.” 

Not only did Soares have to contend with her own grief, she also had to share the news with Page’s parents in Australia and her two sons, ages 7 and 9, who had “adored” him. 

“We’re all just devastated. He was the most wonderful human I’ve met in my whole life.”

The two other men aboard the Great Slave Helicopters aircraft have been identified as Benton Davie, a helicopter engineer from Yellowknife, and Marcus Dyck, a leading Canadian polar bear scientist.

The purpose of the trip had been to survey the Lancaster Sound polar bear population.

The first date and the last message

Soares said she and Page met in Whitehorse last summer, while he was working on contracts with Great Slave Helicopters. 

“We just hit it off right away and become best friends.” 

Soares said Page had lived in Yellowknife, but he started living with her in Whitehorse, with her boys, in between contracts. He moved to Canada about five years ago, she said.

“He had this passion for life and lust for adventure, and I know that he would be whispering in my ear right now telling me to get up and keep going. Go for a hike. Do yoga. Live your life,” she said. “So we’re all going to try and do that, to honour his memory.” 

Their first date, said Soares, had been up Grey Mountain near Whitehorse. 

Page had lived in Canada for five years, and grew up in Queensland, Australia. (Submitted by Sandra Soares)

“I wanted to show him where the cave was, but I wasn’t entirely sure where the cave was, which he kind of thought was hilarious being a pilot. He’s very good at navigation.” 

Soares said she went by the name “Lou,” with Steve, and it was in true “Lou and Steve fashion” that they ended up bushwhacking their way up and finding a second cave.

Sandra Soares said Page had been living with her and her two sons in Whitehorse between contracts with Great Slave Helicopters. (Submitted by Sandra Soares)

“So we wrote in that little notebook that, ‘There’s another cave! From Steve and Lou.’ So if anyone’s up there, that was us, breaking the news.” 

The pair messaged daily, using a satellite communication device when he didn’t have cell service, she said. The afternoon of the crash, he told her he was longing for better food at the camp where he’d been staying.

“He was looking forward to a hot breakfast,” she said. “Looking forward to a hot breakfast and that he was heading out to Resolute. That was the last time I heard from him.” 

Open-minded, non-judgmental

Soares said she’s thankful for the sense of courage she received from her partner, and for the way he would encourage adventure in her life and her sons’ lives. 

“Anyone he meets will fall in love with him. He has this smile that just lights up a room,” she said. “He was open to anything I wanted to talk about; I never felt judged. And I think that’s something he offered a lot of people — just an open space to be themselves.”

The Transportation Safety Board of Canada is investigating the April 25 crash. It said Thursday it would be deploying a team of investigators to gather information and assess what happened. 

The independent agency looks into incidents involving air, marine, pipeline and rail transportation with a goal of improving safety. It does not assign fault or determine civil or criminal liability.

With files from Jane Sponagle

Offshore helicopter crew recovers from inadvertent descent to 13 feet above water near Sable Island, Nova Scotia

Dartmouth, Nova Scotia, 27 April 2021 – In its investigation report (A19A0055) released today, the Transportation Safety Board of Canada (TSB) found that, while conducting a visual approach to an offshore helideck platform in instrument meteorological conditions (IMC), a Sikorsky S-92A helicopter inadvertently entered a low-energy state descent. The pilots were able to stop the descent and regain control within approximately 13 feet of the water.

On 24 July 2019, at 11:54 Atlantic Daylight Time, a Canadian Helicopters Offshore (CHO) Sikorsky S-92A helicopter departed Halifax/Stanfield International Airport, Nova Scotia, on an instrument flight rules flight. The helicopter was headed to the Thebaud Central Facility, an offshore platform southwest of Sable Island, Nova Scotia, with two pilots and 11 passengers on board. Two instrument approaches were attempted at the platform; however, landing was not possible due to low clouds and poor visibility.

Following the second approach, the flight crew acquired visual contact with the platform, visible above a fog layer, and elected to carry out a visual approach. Shortly after they commenced the visual approach, a high-rate-of-descent and low-airspeed condition developed in low-visibility conditions. During the descent, the helicopter’s engines were over-torqued, reaching a maximum value of 146%. The flight crew regained control of the aircraft at approximately 13 feet above the water. During the subsequent hand-flown climb, a second inadvertent descent occurred but the situation was rectified in a timely manner. The aircraft then returned to Halifax/Stanfield International Airport without further incident. The extent of the helicopter’s damage is unknown, as it has been removed from service. There were no injuries.

The investigation determined that instrument meteorological conditions existed at the time of the occurrence, which created a degraded visual environment that was highly conducive to spatial disorientation and provided inadequate cues to permit a visual approach to the Thebaud Central Facility. In an attempt to complete their assigned task within self-imposed time constraints, the pilots’ decision-making process was influenced by their past experience and ease with each other. As a result, they attempted a non-standard visual approach in a degraded visual environment, without thoroughly considering the risks or alternative options.

The investigation also found that CHO’s standard operating procedures provided flight crews with insufficient guidance to ensure that approaches were being conducted in accordance with industry-recommended stabilized approach guidelines.

The pilot flying’s workload increased during the approach when he depressed and held the cyclic trim release button, which contributed to the control difficulties that were encountered. If manufacturers’ flight manuals and operators’ standard operating procedures do not include guidelines for the use of the cyclic trim release button, it could lead to aircraft control problems in a degraded visual environment due to the sub-optimal use of the automatic flight control system.

The investigation also found that the S-92A’s enhanced ground proximity warning system (EGPWS) provides no warning of an inadvertent descent at airspeeds below 50 knots when the landing gear is down. As a result, the EGPWS did not alert the flight crew of the impending risk of controlled flight into terrain. Since there is currently no requirement for commercial helicopters to be equipped with an EGPWS, nothing prevents a manufacturer and/or operator from inhibiting modes of an installed EGPWS, which in turn degrades the system’s capabilities.

In 2016, the TSB issued Recommendation A16-10 calling for terrain awareness and warning systems for commercial helicopters that operate at night or in IMC. Until EGPWS / helicopter terrain awareness and warning systems become mandatory for Canadian commercial helicopters that operate at night or in IMC, flight crew and passengers aboard these flights are at increased risk of controlled flight into terrain.

Following the incident, CHO took several safety actions and subsequently requested the suspension of its air operator certificate since it no longer had any aircraft in its possession, nor did it have any ongoing contracts.

See the investigation page for more information.

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.

Interrupted checklist procedures contributed to 2020 runway excursion in Dryden, Ontario

Winnipeg, Manitoba, 14 April 2021 — In its investigation report (A20C0016) released today, the Transportation Safety Board of Canada (TSB) found that an interruption while conducting checklist procedures and an incomplete checklist led to the February 2020 runway excursion involving an aircraft operated by Perimeter Aviation Ltd. at the Dryden Regional Airport, Ontario. One passenger sustained serious injuries.

Occurrence aircraft after coming to a stop (Source: Ontario Provincial Police)

Occurrence aircraft after coming to a stop (Source: Ontario Provincial Police)

On 24 February 2020, the Fairchild SA227-DC Metro 23 aircraft operated by Perimeter Aviation as Bearskin Airlines flight 344 was conducting a flight from Dryden Regional Airport, Ontario, to Sioux Lookout Airport, Ontario, with two crew members and six passengers on board. At 1610 local time, as the aircraft commenced its take-off roll, directional control was lost which caused the aircraft to exit the right side of the runway and come to rest approximately 18 m off the side in about 46 cm of snow. The aircraft was substantially damaged. The flight crew and passengers egressed through the main cabin door.

The investigation found that while the crew was carrying out the “Before Taxi” checklist, the task of disengaging the propeller start locks was initiated; however, it was interrupted and not completed. After the captain told the first officer to stand by, the crew’s focus shifted to other tasks. It is likely that this slip of attention resulted in the engine power levers not being pulled over the flight idle gate to release the start locks. The “Before Taxi” checklist did not contain a task to ensure that the start locks had been released and, as a result, the crew began taxiing unaware that the right propeller start locks were still engaged. It was determined that, during the takeoff roll, the power was advanced through 20%, but the “positive torque” call required by standard operating procedures was not made, and the engine torque differential was not noticed by the crew. As a result, power lever advancement continued although the right engine thrust remained near zero. The engaged start locks prevented the right propeller from producing the required thrust, which resulted in a significant thrust differential. With less thrust being generated by the right engine, the aircraft experienced a loss of directional control and exited the runway. The injuries to the passenger resulted from propeller blade fragments penetrating the cabin wall during impact with a frozen snowbank.

Following the occurrence, Perimeter Aviation changed its procedures and checklists to better ensure that the propeller start locks are disengaged before taxiing and to raise awareness and understanding of the Metro aircraft’s propeller start lock system. The company also enhanced training for less experienced flight crew members.

See the investigation page for more information.

Fatal accident near Racine, Quebec, highlights risks of flying under visual flight rules in deteriorating weather at night

Dorval, Quebec, 23 March 2021 — The Transportation Safety Board of Canada (TSB) today released its investigation report (A19Q0153) into a fatal loss of control and collision with terrain of a Cessna 172M aircraft near Racine, Quebec, in 2019. The investigation report highlights the risks of flying at night under visual flight rules (VFR), and the lack of clarity in Transport Canada (TC) regulations regarding visual references at night.

On 4 September 2019, a Cargair Ltd. Cessna 172M aircraft departed Montréal International (Mirabel) Airport, Quebec, for a night VFR training flight to Sherbrooke Airport, Quebec, with only the pilot on board. At approximately 19 nautical miles (NM) northwest of Sherbrooke Airport, the aircraft encountered instrument meteorological conditions (IMC) and disappeared from radar. The wreckage was found three days later, on 7 September 2019, in a heavily wooded area near Racine, Quebec. The aircraft had struck trees and had been destroyed by impact forces. The pilot received fatal injuries on impact.

The investigation found that when the plan for the night flight was reviewed by the flight instructor, the ceiling and visibility forecast were assessed as acceptable for the VFR night flight, and the training flight was authorized. Approximately 32 NM northwest of Sherbrooke Airport, the pilot lost visual reference to the surface and descended to 3000 feet above sea level to continue the flight towards Sherbrooke. This descent to regain visual reference, and then to remain clear of cloud, was the first indication that the weather ahead may be deteriorating. After entering IMC, the pilot was likely affected by an unconscious cognitive bias and her proximity to Sherbrooke Airport, Quebec, which led her to continue the VFR flight into deteriorating weather conditions.

As the aircraft neared the Sherbrooke Airport, the pilot inadvertently encountered IMC for a second time, which resulted in a loss of visual reference to the surface. Given the established correlation between loss of visual references and a loss of control, it is highly likely that the pilot, who had limited experience flying by sole reference to instruments, lost control of the aircraft as a result of spatial disorientation.

The TSB has previously investigated a number of similar occurrences, including its recently released investigation report into a loss of control and collision with terrain of a privately registered Piper PA-32-260 (A19O0178). In 2016, the Board issued a recommendation (A16-08) for TC to clearly define the visual references required to reduce the risks associated with night VFR flights. As shown in this occurrence, if the Canadian Aviation Regulations do not clearly define what is meant by “visual reference to the surface,” night flights may be conducted with inadequate visual references, which increases the risks associated with night VFR flight, including controlled-flight-into-terrain and loss-of-control accidents.

Following the occurrence, Cargair Ltd. revised its list of airports authorized for dual and solo night flights, and put in place restrictions on solo night flights for both licenced and non-licenced pilots training at Cargair Ltd.

See the investigation page for more information.

TSB Release of Iran’s Final Safety Investigation Report into the Downing of PS752

From: Transportation Safety Board of Canada


Kathy Fox, TSB Chair
Natacha Van Themsche, Director of Investigations (Air)
18 March 2021

Check against delivery.

On January 8, 2020, Ukraine International Airlines flight 752 was shot down shortly after taking off from Tehran’s international airport, killing all 176 people on board, including 55 Canadians, 30 permanent residents and dozens of others with ties to Canada. Within a few short hours following this tragedy, the TSB advised Iran’s Aircraft Accident Investigation Board (or AAIB) that we would appoint an Expert in accordance with Annex 13 to the Convention on International Civil Aviation and we accepted Iran’s invitation to visit the accident site. From that day forward, we have been fully engaged in doing as much as possible to find out what happened, why it happened and what needs to change to prevent such a tragedy from happening again.

As a matter of practice, the TSB does not comment on reports from other agencies. However, given this unprecedented situation, where the state whose military was implicated in the event led the investigation, and given its impact within Canada, we feel that it is important to publicly convey our independent assessment of the final report. 

But before I discuss the contents of Iran’s final investigation report, I will speak briefly about the investigation process itself.

First, I’d like to remind everyone that a safety investigation is not intended to attribute blame or determine civil or criminal liability. Other processes are better suited for that. Experience has shown that an independent and thorough safety-focused investigation usually offers the best chance of finding out what really happened and why, providing the answers that everyone is asking for, particularly the families who lost so much.

ICAO Annex 13 prescribes the roles of participating countries, including which state has the right to lead the investigation, and which other states may participate and to what extent. It should be noted that, in the case of PS752, the Transportation Safety Board of Canada had no jurisdiction to lead or conduct a parallel investigation.

From the very beginning, Iran offered the TSB more access to the investigation activities than we were technically entitled to, but less than what we asked for. For example, two TSB investigators spent six days in Tehran following the crash, visiting the accident site, examining the wreckage, and meeting with Iranian safety investigators to review information gathered by their team. Later, they also met with Iranian, Ukrainian, and French investigators in Kiev before returning to Canada.

In July of last year, our Expert and a TSB recorder specialist attended the readout of the aircraft’s flight recorders in Paris. Throughout the course of the investigation, we were in direct contact with Iran’s AAIB and attended many discussions with the other participating countries. However, in spite of multiple requests, we were never formally accorded the higher status of accredited representative and hence were not allowed to listen to the cockpit voice recorders or directly access the flight data recordings.

At Ukraine’s request, in early February of this year, we were invited to provide them technical assistance, and Ukraine gave us access to the draft safety report for review and comments, something we would not otherwise have been entitled to.

Throughout this process, we have specifically asked Iran’s AAIB to answer 3 important questions –

  • What was the sequence of events, including the technical, human and organizational factors, that led to the missiles being fired and ultimately the downing of PS752?
  • What was the basis for the decision to keep Iran’s airspace open during a period of heightened military alert after Iran had launched missiles into Iraq?   and
  • Why did civilian airlines continue to operate in Iran’s airspace in the hours following Iran’s launch of missiles into Iraq?

In addition, we submitted dozens more detailed questions related to these 3 main lines of inquiry, that we believed the final investigation report needed to address in order for it to be seen as thorough and credible.

Since receiving Iran’s draft investigation report, our team has carefully reviewed and analyzed its contents and has now compared it to the final report.  Today we want to share our perspective discussing how the report answers the 3 main questions.

Sequence/factors leading to the shootdown by the Islamic Revolutionary Guard Corps (IRGC)

Iran’s final report concludes that PS752 was shot down because an air defense unit mistook the B737 aircraft as a threat. This misidentification reportedly occurred because of a misalignment of the missile launcher’s radar. Furthermore, the operator did not receive permission to shoot from senior officers, as he should have. To date, Iran has provided no evidence to support this scenario; however, it is a plausible explanation for what happened. The report does not provide detailed information regarding how the misalignment occurred, nor what steps were taken to ensure it was properly calibrated, the missile operator’s training, experience, or proficiency, nor about how or why the required communications with central command were either not followed or were unsuccessful. The report frames this action in the context of the heightened military alert given their expectation of retaliation following Iran’s earlier launch of missiles against Iraqi air bases housing U.S. military personnel but does not discuss what supervision or oversight was provided of field operations by Iran’s command and control system. The AAIB says that military activities fall outside of the scope of an Annex 13 investigation– we do not agree.

Nor does the report discuss what steps the Islamic Revolutionary Guard Corps has taken since then to identify the underlying safety deficiencies that allowed such an error to occur, nor what safety action has been taken to prevent such a mistake from happening again. Without this, how can the international civil aviation community be reassured that such a tragic error won’t happen again?

Why did the airspace remain open?

Iran’s final report generally explains the risk assessment process and mitigations that its civilian authorities took in coordination with the military, given the uncertainty of a retaliatory strike following their launch of missiles into Iraq. For example, the report says that Iran gradually cleared air traffic from using certain air routes to the west, from which direction they thought a retaliatory strike might come, and required military approval for each aircraft’s departure from civil airports such as Tehran’s International airport. However, Iran did not completely close its airspace to civilian aircraft.

Why did commercial airlines continue to operate?

In spite of being in a state of heightened military alert, Iran did not publish any notices to warn aircraft operators of these hazards, as recommended by ICAO, until after PS752 was shot down. The U.S. Federal Aviation Administration did post a warning; however, this notice would not have been readily available to Ukraine International Airlines, nor other foreign operators outside of the U.S. Furthermore, Ukraine International Airlines was not the only airline to continue operating after Iran launched missiles against Iraq; eight other aircraft departed Tehran, before the shootdown of PS752.


This report only partially explains why the airspace remained open and why operators continued to fly after Iran had launched missiles into Iraq. It does not explain any of the underlying factors behind why the missiles were launched at PS752, the stated cause of this tragedy. In short, the report says what happened, but doesn’t address the why.

The report indicates that some unspecified safety actions have since been taken to reduce the risk of this happening again. However, the lack of detail means we can’t confirm that these actions will actually reduce the risks to civil aviation operations within Iran’s airspace.

Furthermore, although the AAIB has issued some recommendations, these don’t specifically address the stated cause of this tragic event – the launching of the missiles. 

We know that this has been very difficult for the families. In the end, no safety investigation report can ever bring back those who were lost. And so we must look to what has been learned and what can be done to reduce the risk so that other families don’t have to suffer through this in the future.

We know that states will continue to engage in hostilities with other states, or within their state. And in such a hostile environment, there will always be a risk to civilian aircraft. Innocent lives can be lost. It is the responsibility of the state to reduce those risks.

So the best way to reduce the risk of such tragedies in the future is to firmly apply the lessons learned first, from the downing of Malaysia Airlines Flight 17 and now, from this tragedy.

More needs to be done to protect international civil aviation from operating in conflict zones. In a follow-up report to its investigation into the 2014 downing of Malaysia Airlines flight 17 over Ukraine, the Dutch Safety Board warned (and I quote): “Practice shows that States in which there is an ongoing armed conflict will not implement restrictions for their airspace on their own initiative.”

While ICAO has taken some action it wasn’t enough to prevent this occurrence. Transport Canada is now leading an initiative – Safer Skies – to improve the safety of air travel worldwide by addressing gaps in the way the civil aviation sector deals with conflict zones. Such initiatives offer the best hope for the future to avoid another PS752.

In closing, I know much concern has been expressed about the international protocols that govern the conduct of these very unique types of safety investigations involving military activities, specifically the issue of the state of occurrence investigating itself. Additionally, when a state’s accident investigation agency is not independent of the state aviation authority as required by ICAO, such as Iran’s AAIB, it can affect the credibility of the final report findings and the uptake of resulting recommendations intended to prevent future accidents.

Now that this safety investigation has concluded, the TSB is committed to advocating for a review of the provisions of ICAO Annex 13 to improve the credibility and transparency of such future safety investigations so that families and the public can have confidence in their findings and recommendations.

Pilot decision to fly to B.C. fish camp in poor weather cited by TSB in deadly crash

From City News 1130 – link to source story


RICHMOND, B.C. — The Transportation Safety Board of Canada says a decision to continue flying in poor weather to a remote British Columbia fishing lodge in July 2019 led to a float plane crash that killed four people and injured five others. 

The TSB says the plane left Vancouver airport’s water aerodrome on July 26, 2019, for Calvert Island on B.C.’s central coast despite poor weather forecasts for the area.

The investigation report says the pilot continued flying in bad weather and reduced visibility, and was not able to determine the Cessna 208 Caravan’s proximity to rising terrain, crashing into a hillside on Addenbroke Island, about 17 kilometres from the fishing lodge.

The TSB says the float plane was equipped with flight data monitoring equipment but was not required by regulation to establish a flight data monitoring program.

The TSB investigation says air operators with flight data monitoring equipment that do not actively monitor their flight operations may drift toward unsafe practices that increase the risk to flight crew and passengers.

The pilot died in the crash and the three male passengers who were killed were from South Carolina, Washington state and Germany.

The TSB says four passengers were seriously injured and one received minor injuries.

This report by The Canadian Press was first published March 10, 2021.

Fatal northwest B.C. helicopter crash possibly caused by rain, says investigation report

From CBC News – link to source story

Transportation Safety Board report into summer 2020 crash says lack of black box data hampered probe

The Canadian Press · Posted: Mar 09, 2021

The Transportation Safety Board says poor weather could have played a role in a fatal helicopter crash in the mountains near Stewart, B.C., last summer. (Betsy Trumpener/CBC )

Heavy rain creating an optical illusion on the windshield of a helicopter could have played a role in a fatal crash in northwestern British Columbia last summer, but the Transportation Safety Board says without onboard recording devices it’s impossible to determine the exact cause.

The board released its investigation report Tuesday into the August crash of an Aberdeen Helicopters Ltd. aircraft that was under full power when it hit the upper part of a mountain northwest of Stewart, killing the pilot.

The report finds the pilot was well rested, highly trained and had more than 200 hours of flight time on the Airbus Helicopters AS 350 B2 when it went down.

There was also no indication of mechanical or structural problems with the helicopter. Its work moving sections of a drill rig from one area of an exploration site to another had been trouble-free in the hours before the crash.

Investigators point to sudden heavy rain as one possible reason for the crash, noting that rain, especially on sloping windshields, can create a “refraction error” that makes either the horizon or oncoming objects appear lower.

TSB reiterates call for mandatory ‘black box’

But the report also says that after such an accident, an investigation “may never be able to determine the exact causes and contributing factors” unless the aircraft is equipped with an on-board recording device.

The board repeats its recommendation for a Department of Transport order making lightweight flight recording systems mandatory on commercial and private aircraft that aren’t currently required to have them installed.

Transport Canada is making “positive” progress on that recommendation, the board report says.

“However, until the regulations are finalized, the risks associated with the safety deficiency … will continue to exist.”