The US Air Force and Boeing have completed an interim baseline review (IBR) for the KC-46A aerial refuelling aircraft.

The completion of the IBR, which is a formal review conducted by the government in cooperation with the contractor team, marks the first major schedule milestone for the USAF tanker aircraft programme.

USAF spokeswoman Jennifer Cassidy said IBRs are intended to provide a mutual understanding of risks inherent in contractors’ performance plans and underlying management control systems.

Under the tanker programme, the USAF intends to buy 179 KC-46As to replace the aging KC-135 fleet.

The first 18 KC-46As are scheduled for delivery in 2017, according to Aviation Week.