A rescue team is searching for possible survivors after a Chilean air force plane carrying 38 people disappeared on its way to Antarctica on Monday evening and is presumed to have crashed, Chilean officials said Tuesday.

The C-130 Hercules took off at 4:55 p.m. local time Monday from the southern city of Punta Arenas, Chile, for what should have been a roughly three-hour trip to a Chilean base in Antarctica. The plane had enough fuel to stay airborne until shortly after midnight Monday, the air force said in a statement Tuesday. But officials have been unable to reach the pilot since losing contact with the flight shortly after 6 p.m. Monday. The pilot did not send emergency signals before the flight went missing, the air force said.

The flight was headed toward Chile’s President Eduardo Frei Montalva air base on King George Island and was last seen crossing the Drake Passage, a body of water between South America and Antarctica that can often be treacherous. Also known as the Sea of Hoces, it connects the South Atlantic and South Pacific oceans. The area where the flight went missing is icy and has extreme temperatures.

The military said it is using four ships, 13 planes and three satellites to search for the missing passengers. According to a flight manifest that the Chilean air force published Tuesday, the plane had 21 passengers and 17 crew members, including members of the military, two contractors and a university student.

President Sebastián Piñera canceled a trip to Argentina and tweeted that he was “dismayed” at the news. He also said Brazil has offered assistance in the search.

Defense Minister Alberto Espina told reporters Tuesday that hopes of finding survivors are slim, but he said “it would be profoundly wrong to lose heart at this moment when we are doing everything humanly possible and with all our the energy and determination.”

Chile built its first base on Antarctica in 1947 and established the Chilean Antarctic Institute in 1963, according to the Scientific Committee on Antarctic Research. The air force said the group flying Tuesday was traveling to the base to check on a key floating pipeline that provides power to the base.