SOUTH COUNTY : Marine Copter, Jet Crash; No Injuries

Three crew members escaped injury Wednesday when a Marine Corps helicopter crash-landed in the rugged Santa Ana Mountains, authorities said. A few hours later, another Marine Corps pilot ejected safely before his jet fighter plane crashed in the Pacific off San Clemente Island.

The helicopter mishap, which occurred during a morning flight-training maneuver under clear, sunny skies, involved a type of aircraft that has been linked to numerous accidents, including one that killed 19 Marines last year.

Fire crews responding to the 10:20 a.m. emergency radio calls said the craft, a CH-53D Sea Stallion, fell onto a ridgetop landing pad almost immediately after takeoff.

Federal Aviation Administration spokesman Fred O’Donnell said “unspecified mechanical problems” forced the aircraft down.

El Toro Marine Corps Air Station spokesman Lt. Gene Browne said the helicopter sustained “extensive damage.” He described the incident as a “hard landing” that was “a little less than perfect.” But he declined to comment on the cause of the accident, saying it was under investigation.

The Marines regularly use the pad, called Site No. 11, to practice mountain area helicopter landings, Browne said. It is located a few miles north of Cleveland National Forest, in the upper reaches of Harding Canyon, according to a U.S. Forest Service dispatcher.

According to military records, the Sea Stallion has been involved in a least 17 serious accidents since 1980 and more than 80 servicemen have died in crashes involving the CH-53D model since 1984.

The fighter jet crash, meanwhile, involved a Harrier II vertical takeoff and landing craft. The plane went down during what a Marine Corps spokesman said was a routine carrier landing qualification exercise near San Clemente Island, about 70 miles off the coast from San Diego.

The pilot and plane were assigned to Marine Attack Squadron 311 stationed at the Yuma, Ariz., base.