C-17A ARMS-IA Engine Inlet Repair at McChord Air Force Base

A RECENTLY-signed arrangement with the United States has expedited No. 36 Squadron getting one of its C-17A Globemasters back on mission.
A recently-signed arrangement with the United States has expedited No. 36 Squadron getting one of its C-17A Globemasters back on mission.
The aircraft – which had suffered a cracked engine inlet during a mission to Alaska in late August 2019 – was repaired under the Aircraft Repair and Maintenance Service – Implementing Arrangement (ARMS-IA).
The arrangement allows C-17A technicians from the Royal Australian Air Force (Air Force) and United States Air Force (USAF) to work on each other’s aircraft.
Even though Air Force and USAF C-17As are exactly the same, the maintenance workforces from both countries differ significantly in how they are qualified in their role.
The inlet repair marked the first time that USAF technicians have supported an Air Force C-17A under the arrangement.
In July 2019, technicians from No. 36 Squadron supported two USAF C-17As requiring maintenance in Australia.
Warrant Officer (WOFF) Pete Ranson, WOFF of Engineering for No. 36 Squadron, said the crack on the engine inlet was located on the anti-ice duct – the bare metal ring on the ‘lip’ of the engine housing.
“The jet arrived at Elmendorf Air Force Base in Alaska on August 30 2019, and the crack was detected a part of the post-flight inspection,” WOFF Ranson said.
The anti-ice area of the inlet ensures ice doesn’t form on the front of the engine housing whilst flying in moist air.
Left unrepaired, a cracked inlet could have potentially catastrophic results for the engine housing and C-17A alike if it came apart in air.
For No. 36 Squadron, the first order of business was to decide where the repair would need to be conducted.
Australia is signatory to the Globemaster III Integrated Sustainment Program, which sources spare parts from the nearest warehouse – including in the United States.
Whilst Elmendorf Air Force Base is home to a USAF C-17A squadron, the nearest replacement inlet was at McChord Air Force Base near Seattle in Washington State.
“Due to the size of the part, it was decided that it was more expedient to fly the aircraft to the inlet, versus transporting the inlet to the aircraft,” WOFF Ranson said.
“Boeing released an engineering disposition to stop drill the crack, and authorised a one-time ferry flight from Elmendorf to McChord.”
“The amount of cracking was deemed acceptable enough to allow a short ferry flight.”
Once at McChord, maintenance personnel from the USAF’s 62nd Maintenance Squadron worked to change the engine inlet under Air Force supervision.
The engine inlet measures 1.99 metres in diameter and weighs 248.5 kilograms.
While not regarded as a difficult item to remove and fit to the engine cowling, the inlet still requires a crane and a steady hand due to its size and weight.
The work was completed over September 3 to 6 2019, and the No. 36 Squadron team was back flying on their mission.
Had the ARMS-IA not been in place to allow for the USAF to support the Air Force on the inlet change, conducting the repair could have taken many more days or even weeks.
“Without ARMS-IA, maintenance personnel would have had to be deployed from Australia to the aircraft’s location,” WOFF Ranson said.
“This would have created an additional burden on the squadron by losing a team of personnel to rescue the aircraft.”
In turn, this would have affected other No. 36 Squadron missions, and Defence operations as a whole.
“No. 36 Squadron is often experiencing a high operational tempo, and the longer an aircraft is unavailable, the greater the impact on other missions we’re tasked in support of,” WOFF Ranson said.
“The maintenance workforce is especially aware of the effects of C-17A unavailability.”
With the nature of the C-17A’s strategic airlift work taking it across the world, having ARMS-IA provides greater assuredness for both Air Forces when away on a mission.
“Operating a strategic capability like the C-17A comes with its own unique problems, such as working in different time zones, operating far from home, and often outside our own logistics system,” WOFF Ranson said.
“No. 36 Squadron has benefited from tapping into a global spares program since we introduced the C-17A, and ARMS-IA is providing maintenance support to match this.”