The US has decided to make minor changes in the multibillion-dollar contract pertaining to the air force’s KC-X Stratotanker competition.

The Pentagon has now decided to adjust the projected fuel cost assumptions in the draft request for proposals, and may extend the period covered under life cycle costs from 20 years to 40 years, according to Reuters.

As part of the KC-X acquisition programme, the air force will begin replacing its aging tanker fleet with a planned purchase of new 179 tanker aircraft.

Equipped with a flying boom to provide fuel transfer and a drogue to refuel probe-equipped aircraft, the KC-135 Stratotanker is used to refuel aircraft during flight.

The KC-X tanker competition, currently requires the bidders to meet 373 requirements.

Pentagon will evaluate additional non-mandatory requirements, as a sort of tie-breaker, if the bids were within 1% of each other.