The US Air Force awarded Boeing a $2.9 billion contract for 18 additional KC-46A Pegasus tanker aircraft, spares, support equipment, spare engines and wing air refueling pod kits.

The contract represents the fourth production lot of KC-46A tanker aircraft the USAF has ordered from Boeing and brings the total number of tankers ordered to 52. Ultimately, Boeing expects to build 179 tankers for the service.

The contract comes shortly after the Federal Aviation Administration awarded the Boeing KC-46 tanker a supplemental type certificate (STC) on 4 September, completing the aircraft’s FAA certification process. A US Air Force Military Type Certificate, which covers aerial refueling, defensive, and other military systems, is expected to be granted in the coming months, according to Boeing.

KC-46 refuels A-10 640

The fourth lot contract is a boost for the KC-46 programme which had been plagued by delays and a corruption scandal over its more than a decade and a half saga. The military tanker is based on a commercial Boeing 767 airliner and is the long-awaited replacement for the Boeing KC-135 Stratotanker, a 1950s-era tanker.

The tanker’s boom system can transfer up to 4,540l (1,200gal) of fuel per minute to other aircraft while in flight and its Cobham-supplied hose and drogue systems, located on both the plane's wing and centreline, enable the tanker to refuel probe-equipped aircraft with up to 1,510l of fuel per minute.

In addition to the refuelling mission, the KC-46 can be used to carry passengers, cargo and patients.

The first KC-46 is anticipated for delivery to McConnell Air Force Base in Kansas in October. Then, aircraft will be delivered to Altus AFB in Oklahoma and Pease AFB in New Hampshire.