In an attempt to move Pan Am 1736 off the main runway, controllers instructed Grubbs to turn onto taxiway 3 .In any case, the weather was deteriorating. Grubbs was unfamiliar with Los Rodeos and had trouble locating the correct taxiway in reduced visibility.
Van Zanten, in KLM 4805, had gassed up and was maneuvering toward takeoff himself. He was aware of the Pan Am jumbo, but had no visual contact. He asked for takeoff clearance and was told to stand by. Whether he misheard the instruction, or ignored it, van Zanten proceeded to go. What he didn't know was that Pan Am 1736 was taxiing down the runway directly toward him, still looking for its assigned taxiway.
