The key difference was that the flight plan presented at the briefing corresponded to a track down McMurdo Sound, giving Mount Erebus a wide berth to the east, whereas the flight plan printed on the morning of the flight corresponded to a track that coincided with Mount Erebus, which would result in a collision with Mount Erebus if this leg was flown at an altitude of less than 13,000 feet (4,000 m).
A diferenza clave era que o plan de voo presentado na reunión informativa se correspondía a unha pista por debaixo do estreito de McMurdo, evitando o monte Erebus polo leste, mentres que o plan de voo impreso nesa mañá correspondente a un curso que coincidía co monte Erebus, o que faría que o avión chocase con el se esa parte do voo se realizaba a menos de 13 000 pés (4 000 m) de altitude.