An air New Zealand DC10 carrying 257 persons on a sightseeing flight to the bottom of the world slammed into a volcano yesterday on the ice-bound coast of Antartica, killing all aboard, including 20 Americans. It was one of history's worst air disasters.

A Navy C130 search plane from the U.S. Anartica base at McMurdo Sound spotted the wreckage in the sunlit polar midnight about 1,500 feet up the slope of Mount Erebus, a smoldering, 12,450-foot peak that is one of the world's tallest active volcanoes.

Three New Zealand mountain climbers were dropped by a U.S. helicopter at the crash site early today and reported seeing no sign of life. The tail portion of the giant plane was intact but empty, they said. A search party was on the way overland to the foot of the mountain.

The harsh conditions of terrain, blowing snow and tricky 40-mph winds around the volcano kept Navy helicopters from McMurdo, 30 miles away on Ross Island, from landing at the crash site immediately.

New Zealand Prime Minister Robert Muldoon said bodies would be taken to the base for identification, then flown back to New Zealand, weather permitting.

Erebus is on Ross Island, off the Antarctic coast 2,000 miles south of New Zealand. A low-altitude swing past the volcano is part of the spectacular 11-hour air tour.

The cause of the crash was not known but one Navy spokesman said low clouds covering Mount Erebus might have caused the accident.

"The crew did not report any trouble in their last radio contact" at 2:30 p.m. yesterday, Air New Zealand spokesman Chris Smith said.

The passenger list issued by the airliner indicated 54 of the 257 persons aboard were foreigners: 20 Americans, 22 Japaneese, seven Britons, two Canadians and one person each from Switzerland; Australia and France.

The 20-member crew included well-known New Zealand mountaineer Peter Mulgrew -- an associate of famed Mount Everest conquerer Sir Edmund Hillary -- who gave the passengers a commentary on the sights.

The death toll was the fourth worst ever in world aviation history.

The worst air disaster occured on March 27, 1977, when 582 people died in the collision of two 747 jetliners on the ground in the Canary Islands. On March 3, 1974, 346 people died in the crash of a Turkish DC10 at Ermenonville near Paris -- the worst disaster involving a single plan. On May 25, 1979, an American Airlines DC10 crashed at O'hare Airport in Chicago, killing 273 people, in the worst crash in U.S. history. Today's crash was the fifth fatal accident involving a DC10.

Sen. Harry Byrd (D-Va.) arrived at McMurdo Sound yesterday shortly before the crash to prepare for commemorative events to celebrate the pioneer polar flight of Adm. Byrd, who was his uncle. But officials said the activities were canceled because of the crash.

Staff writer Douglas B. Feaver added from Washington:

Aviation investigators knew little about the accident because of the remoteness of the area and the lack was speculation that turbulent wind of reliable communications. There was speculation that turbulent wind conditions at low altitudes could have created difficulties for the plane.

The National Transportation Safety Board the Federal Aviation Administration and McDonnell Douglas all dispatched experts to join the investigation to be conducted by New Zealand.

Signatories of the Anartic Treaty decided last summer to notify governments of the lack of emergency and rescue facilities in Antartica, the State Department's R. Tucker Scully said.

Scully denied reports that the warning was an effort by the United States to discourage flights over McMurdo Station. "It's not a military base," he said, "It's a logistics facility. The only thing the recommendation was supported to do was to alert people to the lack of search and rescue facilities in the region."