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ASN Wikibase Occurrence # 171666
Last updated: 27 April 2017
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Time:16:36 EDT
Type:Silhouette image of generic A333 model; specific model in this crash may look slightly different
Airbus A330-343
Owner/operator:Air Canada
Registration: C-GFAF
C/n / msn: 0277
Fatalities:Fatalities: 0 / Occupants: 217
Other fatalities:0
Airplane damage: None
Location:Montreal-Pierre Elliott Trudeau Intnational Airport, QC (YUL) -   Canada
Phase: Landing
Nature:International Scheduled Passenger
Departure airport:Frankfurt International Airport (FRA/EDDF)
Destination airport:Montreal-Pierre Elliott Trudeau Intnational Airport, QC (YUL)
The Air Canada Airbus A330 was operating as flight AC875 from Frankfurt, Germany to the Montréal/Pierre Elliott Trudeau airport with 217 people aboard. There was a thunderstorm north of the airport as the aircraft was on approach to Runway 24R in daytime visual conditions. Runway 24R was the only runway in operation, and the flight crew had been advised that the runway lights were out of service. During the final approach, the aircraft entered a heavy rain shower and encountered a strong right crosswind. It then deviated from its path before touching down to the left of the runway centreline. Soon after, the outboard tires of the left main landing gear departed the runway surface for a distance of approximately 600 feet. The aircraft returned to the centreline before taxiing to the terminal gate, where the passengers disembarked without further event.

Findings as to causes and contributing factors:

1. During an approach in the presence of a thunderstorm, pilot-induced oscillation led to the aircraft being in a left bank as it crossed the runway threshold which, combined with a strong right crosswind, resulted in a rapid drift to the left very close to the ground.
2. Once the aircraft crossed the runway threshold, the intensity of the precipitation increased suddenly, such that the pilot flying (PF) had reduced visual references. Under these conditions, the PF did not detect the lateral movement of the aircraft in time to correct the drift before the outboard tires of the left bogie landed in the grass.
3. Given the absence of runway lighting in reduced visibility conditions, it was difficult for the pilot flying to detect the lateral movement of the aircraft over the runway and therefore to prevent the runway excursion.
4. A lateral wind shear generated by a downburst to the north of the runway suddenly increased the aircraft's drift to the left during the landing flare.
5. Runway 24R was not closed in instrument meteorological conditions, even though the runway lighting was not working. As a result, the runway was not equipped with the lights required to enable crews to clearly distinguish the lateral confines of the runway.

Findings as to risk:

1. If airports are not equipped with a low-level wind shear alert system, crews landing there may not be aware of the presence of downbursts or microbursts, and therefore may be exposed to the risk of approach-and-landing accidents.
2. If a crew is unable to verify landing performance in heavy rain conditions involving a risk of hydroplaning, there is an increased risk of runway excursion.
3. If the "landing" response to the "minimum" calls reinforces the notion that landing is assured, there is a possibility that preparation for, and the decision to, go-around could be affected, increasing the risk of a landing incident or accident.
4. If the rain repellent system is unavailable or not used, there is an increased risk, in heavy rain conditions, that crews will lose the visual references necessary to avoid a runway excursion.
5. If a crew does not consider the consequences of multiple threats, there is a risk that pilots will continue a landing under conditions that are not favourable.
6. If the aircraft is drifting near the ground and pilots place the aircraft in low-energy landing regime, there is an increased risk of runway excursion.
7. If crews are not trained to retake the controls at very low altitudes or during the low-energy landing regime, there is a risk that, in the event of a problem, the pilot monitoring will not have time to identify the problem and take the appropriate measures.
8. If TC does not take action to develop the clear standards on avoiding thunderstorms during approach and landing called for in Recommendation A07-01, approaches in the presence of convective weather will continue, exposing aircraft to the multiple, unpredictable hazards associated with thunderstorms.
9. If occurrence sites are not preserved, there is a risk that evidence essential to identifying factors that contributed to an occurrence will be lost.
10. If dispatch is not aware of an aircraft communications, addressing and reporting system transmission failure, there is an increased risk that critical flight information is not received by the crew.

Other findings:

1. Although the wind information at Montréal/Pierre Elliott Trudeau International Airport was transmitted to the flight by air traffic control in a timely manner, the information provided did not enable the crew to be fully aware of the rapidly changing weather conditions in the area of the runway.
2. The runway excursion was not the result of a premature crab angle reduction manoeuvre, which is often associated with landing incidents in crosswind conditions.



Aircraft flight path on approach to Montréal/Pierre Elliot Trudeau International Airport in relation to the available weather information (Source: Google Earth, with TSB annotations)

Revision history:

27-Nov-2014 21:06 peterj Added
28-Mar-2017 14:38 harro Updated [Registration, Cn, Total fatalities, Location, Departure airport, Destination airport, Source]
28-Mar-2017 14:47 harro Updated [Damage, Narrative, Photo, ]

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