New Zealand Prime Minister Jacinda Ardern apologized on Thursday for the then-government's handling of a plane crash in Antarctica 40 years ago that took the lives of 257 people in the country's worst peacetime disaster.

On Nov. 28, 1979, Air New Zealand Flight 901 was on a sightseeing tour from Auckland when it crashed into the side of Mount Erebus, a 3,794-meter (12,448-foot) volcano near the U.S. Antarctic research base of McMurdo Station.

Most of the 237 passengers and 20 crew members killed were New Zealanders; other nationalities included Americans, Canadians, Japanese and Australians.