check the destination waypoint against a topographical map (as did Captain Simpson on the flight of 14 November) or they would have noticed the change. Charts for the Antarctic were not available to the pilot for planning purposes, being withheld until the flight was about to depart. The charts eventually provided, which were carried on the aircraft, were neither comprehensive enough nor large enough in scale to support detailed plotting. These new coordinates changed the flight plan to track east of their understanding. The coordinates programmed the plane to overfly Mount Erebus, a volcano, instead of down McMurdo Sound. About four hours after a smooth take-off, the flight was away from McMurdo Station. The radio communications centre there allowed the pilots to descend to and to continue "visually". Air-safety regulations at the time did not allow flights to descend to lower than , even in good weather, although Air New Zealand's own travel magazine showed photographs of previous flights clearly operating below . Collins believed the plane was over open water. Crash into Mount Erebus Collins told McMurdo Station that he would be dropping to , at which point he switched control of the aircraft to the automated computer system. Outside, a layer of clouds blended with the white snow-covered volcano, forming a sector whiteout – no contrast between ground and sky was visible to the pilots. The effect deceived everyone on the flight deck, making them believe that the white mountainside was the Ross Ice Shelf, a huge expanse of floating ice derived from the great ice sheets of Antarctica, which was in fact now behind the mountain. As it was little understood, even by experienced polar pilots, Air New Zealand had provided no training for the flight crew on the sector whiteout phenomenon. Consequently, the crew thought they were flying along McMurdo Sound, when they were actually flying over Lewis Bay in front of Mount Erebus. At 12:49 pm, the ground proximity warning system (GPWS) began sounding a series of "whoop, whoop, pull up" alarms, warning that the plane was dangerously close to terrain. The CVR recorded the following: GPWS: "Whoop whoop. Pull up. Whoop whoop..." F/E: "Five hundred feet." GPWS: "...Pull up." F/E: "Four hundred feet." GPWS: "Whoop, whoop. Pull up. Whoop whoop. Pull up." CA: "Go-around power please." GPWS: "Whoop, whoop. Pull-" CAM: [Sound of impact] End of recording. The pilots had begun a terrain escape