The Sea Knight model helicopter, of the type that crashed Thursday night in the rugged hills east of Irvine, has been involved in numerous fatal accidents, including a mid-air collision four years ago above the Marine Corps Helicopter Air Station at Tustin.
Although the Navy declined Friday to provide accident data on the large, troop-carrying helicopter, the aircraft, known as a CH-46 Sea Knight, has been involved in at least nine fatal accidents. The worst killed 15 Marines.
A spokesman for Philadelphia-based Boeing Vertol Co., which builds the CH-46s for the Navy and Marines, on Friday praised the helicopter for its performance over the last 23 years.
"They are very reliable machines," said Frank Lake, a company spokesman. "As a workhorse for the Marines it has a good safety record."
Collision at Tustin
Marine officials said Friday that the CH-46E involved in the latest accident slammed into a hillside only minutes after it took off from the El Toro Marine Corps Air Station. All three crew members aboard the Marine Reserve helicopter were killed. The cause of the accident was being investigated, Marine officials said.
In the 1981 mid-air collision involving a CH-46 and CH-53 above the Marine Corps helicopter base in Tustin, officials said the CH-46 was returning to Tustin after nighttime maneuvers when it collided with a Sikorsky CH-53 Sea Stallion helicopter that was practicing heavy lifts at the base. One crew member in the CH-53 survived the crash. The Tustin base is five miles from El Toro.
In 1984, the latest year for which data was obtainable, the CH-46 experienced one of the lowest accident rates of any aircraft flown by the Navy, according to figures published by the magazine Aviation Week & Space Technology. The figures showed that the CH-46 had only 1.97 accidents per 100,000 flight hours. The Sikorsky CH-53, for example, had 6.83 accidents per 100,000 flight hours.
In October, 1985, a Sea Knight carrying 19 Marines crashed into the Atlantic Ocean and sank shortly after it took off from the helicopter carrier Guadalcanal. Fifteen died in the predawn accident.
In February, 1986, two Marines were killed when their CH-46 plunged into the sea off the coast of the Philippines. The helicopter's pilot survived the crash.
Last August, eight Marines died when a CH-46 crashed in the Atlantic Ocean off Norway while it was taking part in North Atlantic Treaty Organization exercises.
In other accidents involving the helicopter:
- Three Marines died in a March, 1982, crash of a CH-46 that went down in mountainous terrain 200 miles south of Seoul, South Korea. The helicopter was participating in joint maneuvers with South Korean forces.
- Two Navy men were lost at sea in July, 1980, when their CH-46 crashed in the Indian Ocean while transferring supplies. One of the crew members was rescued.
- Two Marine helicopter pilots died after their CH-46 crashed in May, 1975, off the coast of Vietnam while they were flying a night search-and-rescue mission from the aircraft carrier USS Hancock.
- Two crew members were killed when a CH-46 Sea Knight crashed and burned in August, 1973, at Yokosuka, Japan. Six Marines survived.
Boeing Vertol produced 624 of the CH-46 for the Marines and the Navy; most were made between 1964 and 1971. The helicopter was used during the Vietnam War.
A spokesman for Boeing Vertol said the helicopter was designed to carry 25 combat equipped troops and an external load of 4,000 pounds. Since it was first produced, Boeing Vertol has continuously upgraded the model.
More Powerful Engine
In 1977, the Navy contracted with Boeing Vertol to install a new, more powerful engine on the CH-46. The new model, equipped with the larger General Electric engines, was known as the CH-46E, the model involved in the crash near El Toro Thursday night.
In December, 1980, the Navy awarded Boeing Vertol an initial contract, followed by more contracts in 1981, 1982, 1984 and 1986, to improve and upgrade the helicopter, including new hydraulics and electrical systems, according to Lake.
The upgrading program was designed to keep the CH-46 fleet in service until the mid 1990s.
CRASHES INVOLVING CH-53 HELICOPTERS
Some recent crashes of the Marine Corps CH-53A, CH-53D, CH-53E and HH-53 (an Air Force model) helicopters. The A and D model copters and the HH-53 have two engines and the E model has three engines.
May 6, 1985 -- A Marine Corps CH-53D Sea Stallion helicopter was flying from Iwakuni to Futenma, Okinawa, over the China Sea when the pilot reported a transmission problem and attempted to set down in the water. Instead, the aircraft crashed, killing all 17 aboard.
July 12, 1985 -- A Marine Corps CH-53D Sea Stallion was on a routine training mission over Camp Butler in Japan when it began spewing gray smoke. It burst into flames and crashed, killing four persons aboard.