Navy vessels searched Saturday for three crew members of a Navy helicopter that crashed during training, killing a fourth crew member, according to The Associated Press. The Navy was operating on the assumption that the missing crew members might still be alive, Navy Lt. Cmdr. Elizabeth Meydenbauer said. «At this point it is still a search,» she said. The identities of the helicopter crew were not immediately released Saturday pending notification of relatives, Meydenbauer said. The cause of the crash was not immediately clear. «The pilot made a mayday call before impacting the ocean but no additional indications of mechanical malfunctions or fire were reported,» Meydenbauer said. The sailor died after being pulled alive from the water, said Navy spokesman Cmdr. Jack Hanzlik. The helicopter was on a training mission when it crashed about 50 miles (80.4 kilometers) off the California coast. The MH-60S, commonly known as a Seahawk, was on a mission directly west of the Camp Pendleton Marine base.