Introduction
On 5 February 2017, an Air Canada Airbus A330-343 (MSN 284) was departing from Brussels Airport (EBBR) for Montreal (CYUL). The aircraft had arrived in Brussels earlier that day at 08:25 UTC from Montreal, with an uneventful landing. The same crew operated the return flight.
Event Description
The aircraft received clearance to line up on Runway 07R at position H. The crew noted that entering the runway required increased power due to an uphill terrain. After receiving takeoff clearance, they initiated the crosswind take-off procedure, a Minimum Equipment List item requiring 1.1 EPR (60% N1) power with brakes applied. Upon brake release, speed built up. Between 60 and 100 knots calibrated airspeed, the crew heard a loud bang, immediately followed by an ECAM warning "brake release." The captain aborted the takeoff. Braking was less effective than expected; the crew deployed thrust reversers, but the right-hand reverser did not deploy. The aircraft decelerated and stopped at intersection C1.
While the crew attempted to contact the tower, the frequency was occupied by a KLM aircraft declaring a pan-pan for fuel shortage. An aircraft lining up behind the Air Canada called the tower and reported witnessing smoke and parts flying from the Air Canada aircraft. The Air Canada crew requested fire brigade assistance twice. Upon arrival, they could not initially communicate with the fire trucks; the tower designated a frequency for communication. The crew shut down the engine to allow the fire brigade to approach the landing gear.
Findings
Investigation revealed that the forward right wheel of the right-hand main landing gear was missing, leaving only the axle and brake. A separated half of a half wheel rim was still present. Hydraulic lines were cut and leaking fluid. The first debris found was the axle cover on taxiway Zulu, near where smoke was first spotted during taxi. Small parts, including bearing rollers, were found on Runway 07R from the start up to position H. Larger parts, including a half wheel rim, were found further down the runway between intersections C3 and C2. The tyre was found nearly intact in the grass to the right of Runway 01, north of F2.
Preliminary Conclusion
The direct cause of the incident was the failure of the outboard roller bearing of wheel #4.