By Olivia Devereux-evans For Mailonline and Associated Press

Published: 20:52 EDT, 30 August 2022 | Updated: 09:32 EDT, 31 August 2022

The US army has grounded its entire fleet of 400 Chinook cargo helicopters after fuel leaks caused engine fires. 

Cynthia Smith, a spokeswoman for the Army, said that the fleet was grounded during the past weekend. 

The leaks were caused by faulty O-rings that were installed in the Honeywell engines of at least 70 aircraft. 

O-rings are used to seal parts of an engine to prevent fuel leaks. None of the pieces found in the affected Chinooks had been produced by Honeywell, the company that makes the engines for the helicopters. It remains unclear who did, or how they ended up in the aircraft.  

 Cynthia Smith, a spokeswoman for the Army, said that the fleet of Chinooks was grounded during the past weekend. Pictured: A file image of a Chinook helicopter 

Honeywell, the engine manufacturer, told DailyMail.com in a statement: '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.

'It is believed these suspect O-Rings have been identified and isolated. 

'The U.S. Army and Honeywell were able to validate that none of the questionable O-rings originated or were part of any Honeywell production or Honeywell-overhauled engines. 

'Joint U.S. Army and Honeywell engineers identified the issue, and are now working with the Army to provide replacement O-rings on all affected Chinooks.' 

The Chinook is the Army's key heavy-lift helicopter, used to transport troops and equipment, and was a familiar sight in the Afghanistan and Iraq wars.

It is now unclear how long the affected aircraft will be out of service, or how it is impacting any ongoing missions or training efforts.

The Army tried to play down the fault, saying in a statement that the helicopters would be back in operation 'soon'. 

The Chinook is the Army's key heavy-lift helicopter, used to transport troops and equipment, and was a familiar sight in the Afghanistan and Iraq wars (file image)

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