The U.S. Air Force chose the KC-30, an adaptation of the European Airbus A-330, to be built by Northrop Grumman (NYSE:NOC) and the European Aeronautic Defence and Space Co. over Boeing's proposed KC-767 tanker.

Boeing said in a statement that the U.S. Air Force assessors concluded that the KC-767 had a greater mission capability and more likelihood of escaping destruction when operating in a combat environment than the larger Northrop-EADS KC-30 tanker.

"The fact that the Air Force gave Boeing the highest possible rating in mission capability and cited the KC-767 Advanced Tanker as having three times more strengths than the Northrop-EADS tanker in this most important category further highlights the inconsistencies in the selection process," said Mark McGraw, vice president and program manager for Boeing Tanker Programs. "As for protecting flight crews on the most dangerous missions, the Air Force evaluated Boeing's tanker as much more survivable than the Northrop-EADS tanker."

Boeing has formally requested the U.S. Government Accountability Office to assess the Air Force's choice.

"Despite the changes made in favor of the KC-30 in the area of mission capability, the evaluation was clear in its assessment," McGraw said. "The Air Force identified 98 strengths and only one weakness with the KC-767, while they pinpointed 30 strengths and five weaknesses for the KC-30, including four weaknesses in aerial refueling."

"Also of significant concern for us is the fact that the Air Force settled for a plane that is ultimately less survivable for flight crews performing their vital missions in war zones," McGraw said. "In providing technology and features that can keep the airplane more survivable for the men and women flying them, the Air Force determined that the KC-30 is less survivable than the KC-767."