The Army grounded its entire fleet of CH-47 Chinooks — about 400 aircraft in all — citing a design flaw that created a potential for engine fires.
The twin-rotor Chinook is the Army’s primary heavy-lift helicopter for troops and materiel in virtually every combat zone the Army enters.
A small number of fires were caused by fuel leaks in a few of the helicopters’ T55 engines, according to the Army. Army spokesperson Cynthia Smith said an “abundance of caution” led the Army to ground the full fleet.
The Wall Street Journal first reported the grounding.
Chinooks have been in service with the Army since the 1960s, seeing combat in every conflict since. Their uses in the Army range from workhorse cargo transports as CH-47s to special operations assaults as MH-47s to high-altitude rescues in Alaska.
The T-55 engines are produced by Honeywell, which said in a statement that “in full coordination with the U.S. Army, Honeywell helped discover that O-rings not meeting Honeywell design specifications had been installed in some T55 engines during routine and scheduled maintenance at an Army Depot.”
The Army did not provide a timeline for returning the Chinooks to the air.