Marines’ Super Helicopter Grounded for Safety Checks

The Marine Corps and the Navy suspended all flights of their accident-plagued, heavy-lift CH-53E Super Stallion helicopter Saturday until inspectors can look at the main gearbox assembly on one of the aircraft’s three big jet engines.

In a terse announcement, the military said the fleet of more than 90 CH-53E helicopters stationed at the Marine Corps Air Station at Tustin and other bases around the world had been grounded. Military officials said they did not know how long it would take to conduct the gearbox inspections but said the procedures would not begin in Tustin, where about half of the CH-53Es are based, until the middle of this week.

The Super Stallion, the largest helicopter made outside the Soviet Union, is capable of carrying 55 combat-equipped troops or lifting 16 tons in equipment. The helicopters can cost up to $24 million each.

But the three-engine aircraft has been plagued by problems since first being delivered to the Marines and Navy in 1980 by Sikorsky Aircraft of Stratford, Conn. The Super Stallion has been involved in six fatal crashes that killed 24 Marines; 17 Marines have been injured in mishaps involving the Super Stallion.

Four of the crashes involved Marines based at Tustin, where about 45 Super Stallions are based in two heavy helicopter squadrons.

The latest fatal crash involving a Super Stallion was Jan. 8 near the Salton Sea Test Range in Imperial County. All five crew members aboard a Tustin-based helicopter perished when it fell into the desert during nighttime landings for troop deployment. Although the military declined to speculate about the cause of the crash, an Imperial County deputy coroner at the scene said it appeared the big helicopter dropped straight down. The coroner said pilot error did not appear to be the cause of the accident.

A Marine spokesman said Saturday that the gearbox inspections were unrelated to any of the fatal crashes of the Super Stallion.

This is not the first general grounding of Super Stallions. The fleet of CH-53E helicopters was grounded in late 1984 following a crash of a Super Stallion in Camp Lejeune, N.C., that killed six Marines and injured 11 others. The aircraft remained grounded until military mechanics and Sikorsky officials inspected the tail rotors, a section thought to be at fault in the Camp Lejeune accident.

The Navy uses a limited number of the CH-53Es to sweep over the water to detect mines. The model is known as the MH-53E.

The grounding notice for the CH-53E came two days after a different model troop-carrier helicopter, based at El Toro Marine Air Corps Station, crashed into Orange County foothills east of Irvine, killing its three crew members. That crash, Marine officials said, had nothing to do with the grounding of the CH-53E. The aircraft that crashed in fog Thursday night was a CH-46E Sea Knight made by the Boeing Vertol Co.

A Marine spokesman said the suspension of Super Stallion operations resulted from what mechanics found when they inspected a CH-53E that made a forced landing on Oct. 21, 1986, in a vacant Irvine strawberry field within sight of the mammoth hangers at the Tustin base.

Unusual Vibrations

Returning from a routine mission, the Super Stallion experienced unusual vibrations and its pilot, Capt. Paul Dittmeier, put the aircraft down in the field, east of the base. No one was injured. The Marines later said the aircraft experienced transmission failure.

That forced landing and the Salton Sea accident in January prompted a new round of concern about helicopter dangers in the cities of Irvine and Tustin, both of which are under helicopter flight paths. At one point, the Tustin City Council voted to write to the Marines asking that the flights routed over their city be discontinued until there was “conclusive evidence” that the Super Stallion was safe.

Rep. Robert E. Badham (R-Newport Beach), who is conducting a congressional inquiry into the Super Stallion, said Saturday that the Navy’s decision to suspend flights of the CH-53E was “a timely demonstration that the Marine Corps is pursuing all the leads on anything that happens.”

Questioned about the time it took the Navy and Marines to find out what was wrong with the helicopter that made the emergency landing in Irvine last October, Badham said the military has “to go over everything with a very heavy surveillance.

“Now they’ve decided to investigate the gearbox,” he said. He also said that the suspension of operations is not really a grounding. “It’s a subtle nuance, but it is different (from grounding),” he said.

Begin Next Week

Sikorsky representatives will be involved when inspections of the main gearbox on the helicopters’ No. 2 engines begin next week, military officials said. Marine Lt. Col. Jerry Shelton of El Toro Marine Corps Air Station said he did not know how long the inspections would take.

In Washington, a Pentagon source told The Associated Press that the main gearbox assembly on the aircraft will be replaced before the helicopter will be allowed to fly, and the replacement process takes at least 10 hours.

A Pentagon spokesman told United Press International that the Super Stallions were grounded after a manufacturing defect was found Thursday in one assembly that goes into the transmission and it was discovered Friday that the problem was widespread.

Further details weren’t available from the somewhat cryptic Marine Corps announcement, issued in Orange County on a Saturday during a holiday weekend.

On Jan. 22, two weeks after the Salton Sea crash, a CH-53D Sea Stallion helicopter, a two-engine model and one that is less powerful than the CH-53E, crashed in the desert near Yuma, Ariz., while on maneuvers. Four Marines were slightly injured. The mishap occurred after an accompanying helicopter, a CH-53A (an earlier model), developed hydraulic problems and had landed. The CH-53D was circling when it crashed.

Has Had Problems

Since the CH-53Es began leaving the Sikorsky factory in 1980 it has had problems with its tail rotor, main rotor, hydraulics and disintegration of bearings, according to Navy reports.

In 1984, four crewmen were killed when a Super Stallion was attempting to lift a truck off the deck of a ship near San Clemente Island off the California coast. According to an analysis of the accident, the sling attached to the truck bounced when the bed of the truck broke lose and the subsequent jolt caused the helicopter to virtually disintegrate.

Some of the military reports show:

- That a CH-53E taxiing just after landing at Tustin was damaged when a bearing in the tail section exploded.

- That a CH-53E landing at the Naval Air Station in Sigonella, Italy, lost hydraulic pressure when its main gearbox cooler fan shattered. Flying parts damaged the oil lines and the rotor drive shaft.

- That during a routine mission in Norfolk, Va., a CH-53E developed problems during its initial climb after takeoff. Bearings in the main transmission had disintegrated.

- That a CH-53E flying in the Philippines was hovering at 60 feet when it lost power to its tail rotor, which sheared off.

In May 1986, a CH-53E was approaching a landing while on a training mission near Twentynine Palms when it crashed. Four crew members aboard the Super Stallion were killed.

The Marines have not released final reports on the cause of the last two fatal crashes of the Super Stallions in 1986 and 1987.

The military and Sikorsky engineers began planning the Super Stallion in the early 1970s when it became evident that the Marines needed a helicopter more powerful that the earlier CH-53A and CH-53D, which could lift only half as much as the Super Stallion.

In 1977, Sikorsky won the contract to produce the CH-53E. Using the basic design of the earlier CH-53D, a third engine was added. Even engineers were surprised that they had doubled the aircraft’s lifting capacity by only increasing the horsepower by 50%.

Mainstay of Fleet

The Super Stallion became a mainstay in the Marines’ helicopter fleet. It is primarily used to move heavy equipment, such as the 105-millimeter howitzer, trucks and even tanks.

Even the earlier models, the CH-53A and D, both known as the Sea Stallion, have been involved in a series of fatal accidents stretching back to 1968. More than 30 Sea Stallion accidents have claimed an estimated 186 lives.

One of the worst occurred when an earlier CH-53D model crashed in Israel in May, 1977, near Jericho in the occupied West Bank. The aircraft lost altitude during nighttime maneuvers, killing 54 Israeli soldiers.

In another accident in Korea in 1984, a CH-53D crashed into a mountain near Widibon during a nighttime maneuver. All 29 persons, including American Marines and Korean soldiers, were killed.

In 1985, the Pentagon issued flight restrictions on all CH-53As and CH-53Ds because of defective parts that could cause rotor blades to snap off during flight. This action effectively grounded all 181 of the aircraft until their rotor hubs and bolts could be inspected. The restrictions were lifted after the inspections.