Boeing, EADS and Northrop Grumman and their major partners have all decided not to bid for a multibillion dollar contract to build 112 new combat search and rescue helicopters for the U.S. Air Force.

The decision seems to leave Sikorsky and partner Lockheed Martin as the lone bidder and presumably winner.

Northrop, which teamed up with Finmeccanica’s AgustaWestland in September to bid for the revised rescue helicopter contract and a separate U.S. Navy competition for a new presidential helicopter, said the decision would not affect the team’s pursuit of the second program.

Northrop spokeswoman Margaret Mitchell-Jones said Dec. 11 that the two companies decided to skip the Air Force competition after a thorough analysis of the service’s final request for proposals, or RFP, which was published in October. Bids are due Jan. 3.

“We’ve reached this conclusion based on an extensive evaluation of customer requirements under the current RFP,” Mitchell-Jones said in a statement.

Meanwhile, Boeing also said Dec. 11 it would not submit bids based on its H-47 helicopter or the V-22 tiltrotor aircraft built with Textron’s Bell Helicopter unit for the new combat rescue helicopter.

Boeing spokesman Damien Mills said the H-47 Chinook and the V-22 “Osprey” had been proven to be the world’s most capable and cost-effective search and rescue aircraft, but their capabilities exceeded the parameters of the Air Force contest.

“While the Chinook and Osprey exceed the parameters of the USAF’s Combat Rescue Helicopter program, they are often the go-to aircraft for the U.S. Army, Marines and Air Force Special Operations Command when needing to extract personnel from dangerous situations,” Mills said.

He said the two aircraft had been used to save lives in conditions where other aircraft could not operate.