 Some of the parts to be removed are no longer on the market or have become very expensive.On 18 November 2015, an E-3G was deployed to the Middle East to begin immediately flying combat missions in support of Operation Inherent Resolve against ISIL, marking the first combat deployment of the upgraded AWACS Block 40/45.The $2.7 billion development effort started in 2003, with the first five aircraft achieving initial operational capability (IOC) in July 2015.