After landing on runway 34R in light rain, the aircraft vacated to the right, via taxiway 'T', continuing to decelerate, with the flaps still in the landing configuration. As the aircraft turned left onto taxiway 'J', the aircraft ran off the paved surface to the right of the taxiway and became bogged in soft wet ground. The crew reported they felt minor slipping during the turn, but were unable to regain directional control by braking action or the application of reverse thrust. The wind was reported as 050/10-15 and there were patches of standing water on the taxiway. A subsequent engineering investigation found no fault with the aircraft or its steering system. The taxiways were constructed with a slight camber, designed to assist water runoff.
Photographic evidence indicated that the aircraft had commenced the left turn whilst on the right side of the centreline. A replay of the recorded surface movement radar indicated that the aircraft entered the turn faster than preceding aircraft, at about the maximum design speed for the taxiway. It is considered likely that the north-easterly wind, acting upon the vertical surfaces of the aircraft, reduced the steering effectiveness of the nose gear in the slippery wet conditions as the aircraft turned from a northerly to a westerly heading on the right side of the cambered taxiway. Corrective action by the crew could not prevent the aircraft leaving pavement.