Northrop Grumman on Wednesday said it had received the US Air Force's amended bid specifications on a 35-billion-dollar aerial refueling tanker contract and would 'review' them. 'Northrop Grumman acknowledges that today it has received the final Request for Proposals (RFP) for the US Air Force KC-X Tanker Modernization Program,' said Randy Belote, spokesman for the US defense contractor that has partnered with European rival EADS for the contract. 'Northrop Grumman will analyze the RFP and defer further public comments until its review of the document has been completed,' he said. The Pentagon on Wednesday unveiled the final terms of a lucrative competition to replace US aerial refueling tankers, saying it gave industry rivals Boeing and Airbus parent EADS a fair chance at winning the deal. 