Northrop Grumman Corp. announced Monday that it won four of five categories established by the Air Force to weigh the awarding of a coveted $35 billion aerial refueling tanker contract.

The Los Angeles defense contractor said its bid was "more advantageous" than rival Boeing's Co. in the categories of capability, price, aerial refueling assessment and past performance.

Northrop, which teamed with Airbus parent European Aeronautic, Defence & Space Co. to win the bid, did not comment on the fifth category of proposal risk.

Northrop's announcement was the second of the day as it finds itself on the defensive from Congressional critics who question why the Air Force gave such a large and critical contract to a joint bid based on a European designed and built aircraft, the Airbus A330.

Earlier Monday, Northrop nearly doubled its estimate of the number jobs that will be created as a result of the contract increasing the total to 48,000 from 25,000. The A330 jet that will form the platform of the KC-45A tanker will be constructed in Europe, but final assembly will take place in Mobile, Ala.

Moreover, a host of U.S. aerospace companies, including 41 in Southern California, will supply parts for the plane. Nineteen of those companies are in Los Angeles County.

Shares in Northrop closed down 62 cents to $78.39 Monday.

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