UPDATE 1-US Air Force delays rescue helicopter selection

(Adds quote, details, background on disputed contract award)

By Jim Wolf

WASHINGTON, Nov 5 (Reuters) - The U.S. Air Force said on Monday it had pushed back to the summer its latest plan to award a hotly contested contract for a potential $15 billion combat rescue helicopter fleet.

The new target for choosing among Boeing Co (BA.N), Lockheed Martin Corp (LMT.N) and United Technologies Corp (UTX.N) is "early summer," said Lt. Col. Jennifer Cassidy, an Air Force spokeswoman, responding to questions from Reuters.

As recently as Oct. 24, Air Force Secretary Michael Wynne told Congress he expected a winner to be named by mid-February. Other senior Air Force officials had said it was likely to be no later than the spring.

At issue is a rerun of a competition to supply 141 combat search and rescue helicopters, known as CSAR-X, the Air Force's No. 2 acquisition priority after a $40 billion plan to start acquiring a new aerial refueling fleet.

The Air Force did not respond to requests to spell out the reasons for the fresh delay in the program to replace aging HH-60G Pave Hawks used to rescue downed pilots. The Pave Hawks have been used heavily in Iraq and Afghanistan.

"I don't know why SECAF said Feb.," Cassidy wrote in an e-mail, referring to the air force secretary's reference to a projected mid-February award.

The CSAR-X contract has been in dispute since Nov. 11 last year, when it was awarded to Boeing for its HH-47, a variant of its tandem-rotor Chinook helicopter. A relatively heavy choice, the choice of the HH-47 drew a public expression of surprise from Air Force Chief of Staff Gen. Michael Moseley.

Lockheed Martin and United Technologies' Sikorsky unit, the loosing bidders, successfully contested the award with the General Accounting Office (GAO), a congressional watchdog.

The companies, which offered single-rotor aircraft, argued the Air Force had failed to properly consider maintenance costs, among other things. They then challenged the Air Force's narrowly drawn terms for a new competition, prompting it to go back to the drawing board again at GAO's request.

Last month, the Air Force released revised draft bidding rules that would let the competitors submit new information in all categories, including technical and cost-related issues.

Boeing said on Oct. 24 it had cooperated with every Air Force request and revision in good faith "and we believe it's time our competitors did the same thing."

Lockheed has teamed with AgustaWestland, a unit of Italy's Finmeccanica SIFI.MI>, to offer its US101, which won a contract to replace the current fleet of U.S. presidential helicopters. Sikorsky is pitching its HH-92, a variant of a helicopter that has been widely used by offshore oil companies. (Reporting by Jim Wolf; Editing by Tim Dobbyn)