The Marine Corps has resolved engine problems that have plagued its new fleet of heavy-lift helicopters, officials announced on Tuesday.
Engineers have fixed mechanical problems on Lockheed Martin-Sikorsky's CH-53K King Stallion, including an exhaust-gas reingestion issue that left the aircraft sucking dirty air back into its engine. It’s a problem the Defense Department warned earlier this year could reduce the helicopter’s power.
The King Stallion is the military’s most powerful helicopter, with an external cargo hook capable of carrying up to 36,000 pounds. But since the Marine Corps accepted its first new CH-53K last year, the program has faced a host of technical problems and budget overages resulting in delays to the target initial operational date, which was originally set for this month.
Government and private sector engineers have been working to determine why the King Stallion was ingesting exhaust gas, said Col. Jack Perrin, program manager for the Navy Department’s H-53 helicopters. Fixes were added to a model aircraft, and they flew “a rigorous series of test flights,” according to a Marine Corps news release on the engine fixes.
Follow-on testing showed the problems with the aircraft ingesting exhaust gas had been repaired, Sikorsky Chief Engineer Steve Schmidt said.
“Our early investment in the CH-53K all digital design enabled Sikorsky and [Naval Air Systems Command] to quickly and precisely model the Exhaust Gas Reingestion situation, analytically predict mitigation approaches, and subsequently build and flight test redesigned components that validated our integrated solution for production,” he said.
Those fixes will now be made on all CH-53Ks heading to the fleet, Capt. Christopher Harrison, a Marine spokesman at the Pentagon, said.
Perrin said the team “hit it out of the park” when coming up with the fixes.
"This is exactly what an integrated test team is supposed to do," he said in a statement. "Bring their expertise to a project, look for resolutions in a dynamic and collaborative environment, determine the best path forward and keep this aircraft on track to the fleet."
The King Stallion has three General Electric T-408 engines, which are more powerful and fuel efficient than those on the legacy CH-53E aircraft.
The Marine Corps currently has 20 CH-53K King Stallions on contract, Harrison said. The aircraft’s first operational deployment is set for 2024.
The service’s plan to buy hundreds of the heavy-lift helos -- which Harrison said cost about $87 million each -- has faced scrutiny from lawmakers after testing identified more than 100 problems.
With plans for dispersed operations across vast distances in the Asia-Pacific region, Marine leaders have said the heavy-lift capabilities of the King Stallion will be vital for future missions.
When problems with the aircraft emerged, Sen. James Inhofe, an Oklahoma Republican and chairman of the Senate Armed Services Committee, instructed the Pentagon try to get aircraft with the same capabilities from another supplier.
But Lt. Gen. Steven Rudder, the Marine Corps’ top aviator, said the CH-53K is the only aircraft “that can do what we’re asking it to do.”
Editor's Note: This story has been updated with comment from Sikorsky.