The Pentagon is preparing the draft rules for the upcoming US Air Force aerial refuelling tanker deal estimated to be worth $35bn.

The US Air Force plans to acquire 179 tanker aircraft through the deal and Pentagon is presently working on the request for proposal of the contract, Reuters reports.

Boeing, Northrop and EADS interested in bidding for the contract have been closely following the developments on the RFP.

The Pentagon had awarded a projected $35bn contract for the new aerial refuelling planes to Northrop in February 2008, however, the deal was scrapped after US government upheld a protest filed by Boeing.

Pentagon spokesman Bryan Whitman was quoted by Reuters as saying that they are going through a very careful and deliberative process.

“Getting this right has been more important than speed. At the same time it has the energy and attention of the department,” Whitman said.

According to industry speculations if the draft RFP comes out in late September 2009, the final RFP would be issued in late November, with bids due in late December 2009 or early January 2010.