An Airbus 330 flying from Montreal to London lost a wheel while taxiing earlier this week and still took off and landed safely at Heathrow. The landing gear is comprised of 8 wheels, so fortunately the loss of 1 wheel did not have a huge impact on being able to land safely. The wheel appears to have become separated while the plane was taxiing and was found next to the runway.
The plane has subsequently been repaired in London before being allowed to take off again. Air Canada has not issued an incident report and no details have been released as to how this incident happened. Flight 864 out of Canada was carrying 294 passengers and no undue roughness was noted on landing and taxiing to the gate.