In 1979 a large passenger jet with 257 people on board left New Zealand for a sightseeing flight to Antarctica and back. Unknown to the pilots, however, someone had modified the flight coordinates by a mere two degrees. This error placed the aircraft 28 miles (45 km) to the east of where the pilots assumed they were. As they approached Antarctica, the pilots descended to a lower altitude to give the passengers a better look at the landscape. Although both were experienced pilots, neither had made this particular flight before, and they had no way of knowing that the incorrect coordinates had placed them directly in the path of Mount Erebus, an active volcano that rises from the frozen landscape to a height of more than 12,000 feet (3,700 m).