SAN DIEGO, Oct 30 (Reuters) - Rescue teams searched the ocean off Southern California on Friday for nine people missing and feared dead after the mid-air crash between a U.S. Coast Guard plane and a Marine Corps helicopter, officials said.The Coast Guard held out hopes for finding survivors but Pentagon spokesman Bryan Whitman said in Washington that the crash had "likely taken the lives of nine individuals."
If all nine perished, it would be the deadliest Coast Guard aviation accident in more than 60 years, crash records show.
Seven crew members were aboard the Coast Guard C-130 transport plane and two were aboard the Marine Corps AH-1 Cobra attack helicopter when the aircraft collided in clear skies and light winds on Thursday evening off San Clemente Island, the Coast Guard said.
The island, owned by the U.S. Navy, is about 70 miles (113 km) west of San Diego.
The Cobra was on a training mission, flying in formation with three other helicopters, while the C-130 was searching for someone missing in a private boat, Coast Guard spokesman Petty Officer Henry Dunphy said.
The whereabouts of that person remain unknown.
Several Coast Guard cutters and air rescue teams converged on an area where crash debris were spotted between San Clemente Island and the San Diego County shore, expanding their search to 644 square miles (1,668 square km) of the Pacific, Dunphy said.
At midday, Coast Guard Rear Admiral Joseph Castillo insisted search teams were still hoping to find crew members alive, saying it was possible for a person to survive in the water for 20 hours or more.
"Our people are very highly trained in survival techniques. They are very highly fit. They're able to survive things you would otherwise be surprised at," he told a news conference.
About 21 hours after the crash, Dunphy said no signs of bodies or survivors had turned up.
"We're still absolutely searching for survivors out there," he said.
Weather in the crash area on Friday was clear and calm.
The accident would rank as the Coast Guard's deadliest air wreck since 10 crew members died in the crash of a Coast Guard plane returning from a mission to Mexico in 1947, according to a website documenting aviation mishaps dating to the 1930s.
It also would rank as the second-deadliest air crash ever for the Coast Guard, a branch of the U.S. armed services that falls under the Department of Homeland Security.
Homeland Security Secretary Janet Napolitano said the government was "providing every available resource to fully support the ... search effort underway to locate survivors of this devastating accident."