Description

On 9 August 2019, a Bombardier CRJ-200LR, (C-GKEJ) being operated by Air Georgian on a scheduled international passenger flight from Toronto to Ohio as CGN7339 commenced takeoff on runway 33R as a Boeing 777-300 (C-FIUR) being operated by Air Canada on a scheduled international passenger flight from Copenhagen to Toronto as ACA883 was crossing the runway at an intermediate intersection after landing in normal day visibility. On seeing the 777 ahead, the CRJ carried out a high speed rejected takeoff and were able to clear the runway well before reaching the intersection at which the 777 was crossing.

Investigation

An Investigation was carried out by the Canadian Transportation Safety Board. It was not able to use relevant data from either the CVR or DFDR of the CRJ200 because the subsequently flown 1 hour flight resulted in the overwriting of the event on 30 minute CVR and the operator failed to secure the DFDR as required under applicable regulations. The Investigation was therefore reliant primarily on recorded ATC data.

It was noted that the CRJ200 Captain, who was acting as PF for the sector, had a total of 3,394 flying hours of which 1,331 hours were on type. The First Officer had a total of 2,445 flying hours of which 995 hours were on type. The TWR controller involved had 24 years’ experience initially at Calgary with the most recent 7 years at Toronto.

What Happened

The CRJ200 taxied for departure from runway 33R on taxiway D (see the illustration below) as the Boeing 777 was landing on runway 33L On clearing the runway, the 777 was instructed to taxi via taxiways F4 and H and contact GND North where the controller instructed the flight to hold short of Runway 33R. A DHC-8 was then cleared for takeoff from the intersection of runway 33R and taxiway B3 and after it had done so, as the 777 was approaching its clearance limit, the GND North controller, having coordinated with the TWR runway controller, instructed the 777 to cross runway 33R “without delay”, aware that the next departure from the runway would be the CRJ200 which was cleared by TWR to line up and given an amendment to the previously issued departure clearance which was read back correctly.

Having noted this correct readback the TWR controller, who was also responsible for arrivals on runway 33L, turned their attention to approaching traffic for that runway. As the CRJ200 lined up, the First Officer finished the line-up checklist and the Captain asked them if they had received a takeoff clearance to which they received the response that they had. As the 777 crossed the holding point for its cleared crossing of the runway, the CRJ200 began its takeoff roll without receiving a corresponding clearance.

The ground track of the CRJ200 (yellow) and the Boeing 777 (green). [Reproduced from the Official Report]

Runway 33R does not have a level profile so the 777 was not initially seen but as the aircraft approached the peak of an elevated section of the runway, it came into view ahead on the runway approximately 1650 metres ahead and a rejected takeoff was immediately commenced with the crew realising that they had probably not received a takeoff clearance. A Runway Incursion Monitoring and Collision Avoidance System (RIMCAS) audible and visible alert was generated in the TWR at about the same time and caused the controller to return his attention to runway 33R. Upon doing so, he reported having “quickly assessed the situation, determined that there was no actual risk of collision and immediately issued a takeoff clearance to the CRJ 200”. The CRJ200 responded by advising that they had already initiated a rejected takeoff and were given an exit taxiway. Radar data showed that the CRJ200 had reached a maximum groundspeed of 99 knots. The flight was subsequently repositioned for takeoff and this was completed without further event. The 777 crew remained unaware of the event as in accordance with Canadian procedures, they had remained on the GND frequency whilst crossing the runway.

Discussion

The “line up” clearance used by the controller was contrary to the applicable Manual of Air Traffic Services (MATS) phraseology which was required if any delay (not defined) to departure is anticipated. However, the controller reported assuming that the CRJ200 crew would have recognised the need for a short delay to their departure because of the much slower (DHC8) aircraft ahead and had therefore chosen not to inform them of a delay or issue a specific instruction to “wait” after issuing the line-up instruction.

In respect of the controller’s tactical assessment that continuing the takeoff would not have been hazardous since he could see that the 777 was about to complete its crossing near to the far end of the runway, this was in line with the MATS guidance which stated that “aborting a takeoff is an emergency procedure used when continuing would present a grave hazard to the aircraft” and that “a controller-initiated aborted takeoff is an extreme measure (to be) used only where no clear alternative exists”. However, the MATS guidance in the event of Stage 2 RIMCAS Alert in the circumstances which had prevailed was noted as requiring the issue of an abort takeoff instruction.

In terms of the sighting of the 777 ahead by the CRJ200 crew, the Investigation considered the geometry of the impeded visibility along the runway caused by its longitudinal profile which reached a maximum elevation at just over one third of the runway 33R length. It was calculated that at the start of the takeoff roll, the top 7.4 metres of the 777’s vertical stabiliser would have been visible approximately 2700 metres ahead. By the time the aircraft approached the crest of the hump, the entire fuselage of the 777 would have been visible crossing the runway approximately 1950 metres ahead.

It was considered that whilst there was no direct evidence that fatigue had played a part in the performance of the flight crew on the day in question, the Investigation found that in general, both pilots appeared to have a degree of difficulty coping with a sequence of rostered duties which usually started with late duties and then transitioned to early ones.

The Findings of the Investigation were formally documented as follows:

There were five Findings as to Causes and Contributory Factors:

1. The number of pre-departure tasks the flight crew was required to complete within a short amount of time increased their workload.
2. The First Officer’s workload was further elevated as she focused on the heading and altitude change of the standard instrument departure amendment, which, at the time, she believed was most important in the line-up instruction.
3. When the First Officer received and read back the line-up instruction with the standard instrument departure amendment, she had misinterpreted that air traffic control communication as a clearance for takeoff.
4. The increased workload, the expectation to receive a take-off clearance without delay and the misinterpretation of the line-up instruction led the crew to initiate the take-off roll without a take-off clearance.
5. The fuselage of the Boeing 777-300 would not have been visible to the CRJ 200 crew at the start of their take off roll because of the longitudinal profile of Runway 33R; therefore, the crew had no visual indication that it was unsafe to initiate the take-off roll on Runway 33R.

There were three Findings as to Risk:

1. Backward-rotating shift schedules cause circadian rhythm de-synchronisation, which increases the risk of fatigue in crew members who do not receive sufficient time off to adapt their sleep-wake pattern when working these schedules.
2. If airlines do not inform crew members of the risk of fatigue due to the direction of shift schedule rotation, there is an increased risk that crew members will operate an aircraft while fatigued.
3. If cockpit voice recorders that have a reduced recording capacity remain in service, there is an increased risk that data relevant to an occurrence will not be available to an investigation, precluding the identification and communication of safety deficiencies to advance transportation safety.

There was also one ‘Other’ Finding:

• Although the ‘Manual of Air Traffic Services’ requires a reject takeoff instruction to be issued when a Stage 2 RIMCAS Alert is triggered, the Tower controller chose not to do this, instead issuing a takeoff clearance because he assessed that there was no risk of collision.

Safety Action taken as result of the investigated event was noted to have included the following:

• NavCanada (as ANSP) issued an ‘Operations Directive’ which reminded TWR Controllers that in accordance with the MATS, if a RIMCAS Stage 2 Alert is activated by a departing aircraft, they must cancel any takeoff clearance already given or issue an instruction to reject one that has already started without such a clearance..
• Air Georgian amended their flight crew SOPs to require a check with ATC if one of the pilots is unsure/unaware of the content of any ATC clearance or instruction. However, it was noted that Air Georgian no longer exists as a corporate entity.

The Final Report of the Investigation was authorised for release on 16 December 2020 and it was officially released on 15 January 2021. No Safety Recommendations were made.

Related Articles

• Runway Incursion
• Take-off without ATC Clearance
• Expectation of Clearance
• Situational Awareness