WASHINGTON (AP) _ Boeing Co. has filed a formal protest of a $35 billion Air Force tanker award it lost to a European rival.

European Aeronautic Defence and Space Co. and Northrop Grumman Corp. won the deal to replace 179 air-to-air refueling tankers.

The award is the first of three major Air Force contracts to replace its entire fleet of nearly 600 aging tankers over the next 30 years.

Chicago-based Boeing says it filed the protest with the Goverment Accountability Office because of irregularities in the contract competition.