U.S. Army Fixes 90% Of Chinooks After Wrong Parts Installed

The U.S. Army grounded its H-47 fleet earlier this year after incorrect parts were installed on engines during depot maintenance.

Credit: U.S. Army

About 90% of the U.S. Army’s Chinook fleet has been fixed and returned to flight after an investigation found incorrect parts were installed on the heavy-lift helicopters during depot maintenance. 

The service announced in August it had grounded its H-47 fleet following a small number of engine fires. The Army and Honeywell, producer of the T-55 engine, said at the time that the issue was O-rings not meeting the company’s design that were installed during routine scheduled maintenance at an Army depot.

Brig. Gen. Tom O’Connor, the commanding general of the Army’s Aviation and Missile Command, says the service used to buy these O-rings directly from Honeywell, but had “transitioned away” from that contract to one that bundled multiple O-rings from another supplier. The problem was not with the depot, but instead a supply chain issue, he says.

The Army removed the engines that were affected, and as of Oct. 10 about 90% of all Chinooks had been fixed, says Maj. Gen. Hank Taylor, director of Army Aviation. The remaining will be repaired “within the year” as they go through normal maintenance, with these powerplants not on aircraft and instead going through an off-wing maintenance cycle.

Taylor says the service was able to quickly mitigate the grounding when it happened through the use of other aircraft, including UH-60 Black Hawks.

Brian Everstine

Brian Everstine is the Pentagon Editor for Aviation Week, based in Washington, D.C. Before joining Aviation Week in August 2021, he covered the Pentagon for Air Force Magazine. Brian began covering defense aviation in 2011 as a reporter for Military Times.