CAPE CANAVERAL, Fla. (AP) _ Air Force, Navy and Coast Guard crews teamed up Monday to rehearse the rescue of astronauts who might be forced to parachute into the Atlantic Ocean from a crippled space shuttle.

The six Air Force men playing the roles of astronauts were safely aboard a 20-man motorized raft, awaiting a helicopter airlift back to shore, 70 minutes after they were dropped into the sea from a boat to simulate their bailout from a shuttle.

Air Force spokeswoman Anne McCauley gave this account of the make-believe shuttle abort and the practice rescue effort:

Shortly after the mock liftoff of a shuttle, one of the three main engines failed and the crew was directed to make an emergency landing on a runway near the launch pad. During the descent, the other two engines failed, and the ''astronauts'' slid from the cabin down a telescoping pole and parachuted into the sea 25 miles east of Cape Canaveral.

Thirteen minutes after the crew hit the water in the simulated bailout, an Air Force HB130 aircraft dropped three pararescue personnel and a seven-man raft into the water. Three more paramedics and another raft were dropped after another 22 minutes.

The 20-man raft was deployed, and the paramedics quickly secured the crew members and put them on board. H3 helicopters transported all 12 of those in the water to nearby Patrick Air Force Base for medical examinations.

Participating in the exercise were a Navy ship and a Coast Guard vessel, two HC130 aircraft and three H3 helicopters. About 150 people took part, including 20 NASA observers.

McCauley said the exercise demonstrated the capability of the combined forces to use command, control and communications procedures to effectively locate and rescue shuttle crew members from the ocean.