Although the timing and even the legality of the KC-X acquisition process remains uncertain, both competitors vying for the roughly $35 billion contract have submitted their last updates to proposals for the US Air Force tanker replacement contract.

The final proposal revisions submitted on 10 February should mark the last major step before contract award, although USAF officials have declined to specify the timing. Boeing and EADS North America executives, however, expect the USAF to make a final down-select in February.

But signing a contract could still prove difficult for two reasons.

First, a critical shipping error committed by the USAF in November sent evaluation assessments to the wrong bidders. That blunder has prompted calls by Boeing's supporters in Congress for an investigation by the inspector general, which may prolong the timing of contract award.

Meanwhile, a political stalemate over the fiscal year 2011 federal budget means the USAF may be prevented from awarding a contract to either company until the appropriations bill is passed.

Todd Harrison, a senior fellow at the Centre for Strategic and Budgetary Assessments, believes the USAF may announce a winning bidder, but signing a contract that launches the development programme may be delayed until the FY2011 budget is approved.

The final proposal revisions allowed both companies perhaps one final opportunity to rattle their competitor.

EADS issued a press statement ridiculing Boeing's proposed KC-767 NewGen Tanker as a "concept", rather than a proven aircraft. By contrast, EADS also claims that the KC-45, which is based on the Airbus A330 multi-role tanker transport, offers a 15-44% saving on operating costs with greater fuel efficiency.

Boeing's statement, however, described the tanker replacement decision as a matter of national security.

"This decision is critical to America's national security and its manufacturing base," Boeing chief executive Jim McNerney said. Boeing also described their tanker as the cheaper option that would save "$36 billion in life-cycle costs compared with the competitor's aircraft".

Source: Flight International