The Government Accountability Office identified seven categories of flaws in the US Air Force's selection process that awarded the KC-X contract to the Northrop Grumman/EADS North America KC-30B:
Wrong metrics: the USAF ignored its own evaluation criteria and neglected to account for Boeing's lead on satisfying an undisclosed list of "non-mandatory requirements".
Extra credit: the USAF gave Northrop bonus points for exceeding the fuel offload threshold, violating its own rule.
No aircraft left behind: the USAF failed to prove that it could correctly assess the KC-30B's ability to refuel all fixed-wing aircraft.
Double-speak: the USAF told Boeing it had fully satisfied a requirement. The USAF later changed its opinion, but did not inform Boeing.
Not just an oversight: Northrop's refusal to provide two years of maintenance support was "unreasonably" judged by the USAF to be an administrative oversight.
Mathematics mistakes: correcting errors in the USAF's cost estimates shows that Boeing submitted the lowest estimated life-cycle cost, not Northrop.
Improper increases: the USAF did not think Boeing's estimates for non-recurring engineering costs were too low, but decided to raise them anyway because Boeing failed to explain them. The USAF also could not prove that its own model for predicting costs was accurate.