ASN Aircraft accident Airbus A330-343 C-GFAF Montreal-Pierre Elliott Trudeau International Airport, QC (YUL)
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Status:Accident investigation report completed and information captured
Date:Saturday 25 December 2021
Time:16:37 UTC
Type:Silhouette image of generic A333 model; specific model in this crash may look slightly different
Airbus A330-343
Operator:Air Canada
Registration: C-GFAF
MSN: 277
First flight: 1999-06-07 (22 years 7 months)
Total airframe hrs:91282
Engines: 2 Rolls-Royce Trent 772B-60
Crew:Fatalities: 0 / Occupants: 10
Passengers:Fatalities: 0 / Occupants: 85
Total:Fatalities: 0 / Occupants: 95
Aircraft damage: Substantial
Aircraft fate: Repaired
Location:Montreal-Pierre Elliott Trudeau International Airport, QC (YUL) (   Canada)
Phase: Landing (LDG)
Nature:Domestic Scheduled Passenger
Departure airport:Fort Lauderdale-Executive Airport, FL (FXE/KFXE), United States of America
Destination airport:Montreal-Pierre Elliott Trudeau International Airport, QC (YUL/CYUL), Canada
Air Canada flight AC901, an Airbus A330-343, suffered a right main landing gear failure while landing on runway 06L at Montreal International Airport, Canada.
A few seconds after touchdown on Runway 06L, the bogie beam failed on the right main landing gear. At the same time, indications of a right main landing gear malfunction were displayed in the cockpit. The aircraft continued its landing roll, with the right gear shock strut scraping the runway, and came to rest on the runway.

The crew requested assistance from aircraft rescue and firefighting services. Significant landing gear damage, which made towing the aircraft impossible, was observed.

Probable Cause:

Findings as to causes and contributing factors:
1. On 17 December 2021, while the aircraft was taxiing for takeoff, for an undetermined reason, one of the bearings on the No. 4 wheel seized and caused the protective sleeve to rub against the bogie beam bushing, causing localized overheating of the bogie beam base metal.
2. Given that the overheat indicator strip closest to the beam at the No. 4 wheel on the axle was its original colour, applicable procedures allowed for the replacement of the axle and the bogie beam bushing without a thorough damage assessment.
3. Given that the component maintenance manual does not provide any specific repair for a bushing replacement, the Disassembly and Assembly sections were used as references. Consequently, the inspection criteria during bushing replacement focused on ensuring the correct dimensions rather than detecting damage, which eliminated the requirement for non-destructive tests.
4. Given the intact indicator strip, the clear transition between the blackened area and the adjacent protective layer, and the intact paint on the beam around the bushing, the technicians who performed the visual inspection during the replacement of the damaged bushing concluded that the beam was in good condition, even though the bogie beam base metal had overheated.
5. Two cracks emanated from a previously undetected area of overheating under the bogie beam bushing. One of the 2 cracks spread and caused a fracture of the No. 4 wheel bore.
6. Upon landing on 25 December 2021, the fracture emanating from the No. 4 wheel bore spread rapidly and resulted in the bogie beam breaking into several pieces. No longer supported by the wheels, the shock strut scraped the runway until the aircraft came to rest.

Accident investigation:

Investigating agency: TSB Canada
Status: Investigation completed
Duration: 1 year and 9 months
Accident number: A21Q0138
Download report: Final report


Runway mishap

» TSB A21Q0138


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This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Fort Lauderdale-Executive Airport, FL to Montreal-Pierre Elliott Trudeau International Airport, QC as the crow flies is 2204 km (1378 miles).
Accident location: Exact; deduced from official accident report.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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