The Army on Wednesday said it cannot specify a timeline for its investigation into fuel leaks causing engine fires on some CH-47 Chinook heavy-lift helicopters that has led to grounding the fleet until it determines the number of affected aircraft.
“Until we determine the full number of affected aircraft, we cannot say how long it will take. Based on the results of our investigation some aircraft may not require corrective measures and may soon return to normal flight operations. However, we have determined the corrective action and will continue to complete maintenance and return aircraft to flight status. Once we know the number of affected aircraft, we will be able to estimate completion time,” Cynthia Smith, an Army spokeswoman, said in a statement to Defense Daily
Smith said the Army’s decision to ground its Chinook fleet, first reported by the Wall Street Journal, was made “out of an abundance of caution” after discovering “the root cause of fuel leaks that caused a small number of engine fires among an isolated number” of the helicopters.
“Based on the results of our investigation some aircraft may not require corrective measures and may soon return to normal flight operations. While no deaths or injuries occurred, the Army temporarily grounded the H-47 fleet out of an abundance of caution, until those corrective actions are complete,” Smith said.
Honeywell [HON], which supplies the T55 engines that power Chinook helicopters, said the company along with the Army identified the issue as caused by O-rings installed on some engines during routine and scheduled maintenance that did not meet the company’s design specifications.
“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,” a Honeywell spokesperson said in a statement.
Honeywell added it’s now working to provide the Army with replacement O-rings for the affected Chinook helicopters.
Boeing [BA] which builds the Army’s CH-47 Chinooks, deferred questions on the grounding decision to the Army.
The Army has operated CH-47 Chinook heavy-lift helicopters since the 1960s and currently maintains a fleet of about 400 of the aircraft.