US Congress has summoned US Air Force officials to a hearing today, 5 March, to explain why Northrop Grumman and Airbus were selected over Boeing for the $35 billion KC-X tanker contract.

Boeing on 4 March requested an immediate debriefing from the USAF on why its KC-767 lost the competition. Announcing selection of the Northrop/EADS tanker in 29 February, the Air Force said it would debrief the bidders on 12 March.

Boeing says the "unusual" delay of almost two weeks is "inconsistent" with established procurement practice, with the debriefing normally occuring within days of the downselect. Losing bidders have 10 days after receiving a formal debriefing to file a protest.

Amid the political furore that has followed selection of the Airbus A330-based tanker, the US House of Representatives has scheduled a hearing for today at which top USAF acquisition officials Sue Payton and Lt Gen Donald Hoffman will testify.

US defence analyst Loren Thompson, who has close ties with the USAF, said on 3 March that Northrop beat Boeing on almost every major KC-X evaluation criterion, including mission capability and cost. "The Northrop-EADS offering was deemed much better in virtually all regards," he said.

“We bid aggressively with specific focus on providing operational tanker capability at low risk and the lowest total life cycle cost,” says Mark McGraw, vice-president 767 tanker programmes, in a statement.

“Initial reports also indicate there may well have been factors beyond those stated in the RFP, or weighted differently than we understood they would be, used to make the decision. It’s important for us to understand how the Air Force reached their conclusion," he says.