SAN DIEGO (AP) – A flotilla of Navy and Coast Guard vessels and aircraft searched off the Southern California coast Saturday for three crew members of a Navy helicopter that crashed during a training flight, killing a fourth sailor.

The Navy was operating on the assumption that the crew members missing since Friday afternoon might still be alive, Lt. Cmdr.

Elizabeth Meydenbauer said Saturday.

“At this point it is still a search,” she said.

The search near San Clemente Island, about 50 miles off the coast, included inflatable boats, two destroyers, a guided missile cruiser, a dock landing ship and Coast Guard ships, Meydenbauer said. Coast Guard and Navy aircraft also were being used.

The MH-60S Sierra helicopter, based at Naval Air Station North Island in Coronado, went down around 5:30 p.m. EST Friday. It was on a mission off the USS Bonhomme Richard.

The pilot radioed a mayday but gave no indications of mechanical malfunctions or fire, Meydenbauer said.

One sailor was pulled from the water but died while being treated on the Bonhomme Richard.

Identities of the helicopter crew members would not be released until relatives were notified, Meydenbauer said.

The Bonhomme Richard is an amphibious assault craft that took Marines to Indonesia after the 2004 tsunami.

The MH-60 Sierra is a twin-turbine craft based on the UH-60L Black Hawk and the Navy’s SH-60B Seahawk, according to the manufacturer, United Technologies Corp.’s Sikorsky Aircraft. It is designed to operate off aircraft carriers, cruisers, destroyers and frigates, ranging up to 100 nautical miles from a ship.

AP-ES-01-27-07 1409EST