By 
PALM BEACH GARDENS, Fla. – Pratt & Whitney, a division of United Technologies Corp. [UTX], is pitching engine upgrades to prolong the life of the U.S. Air Force’s aging B-52 bomber and improve the performance of the new F-35 Joint Strike Fighter, company officials said May 31.For the B-52’s TF-33 engines, which Pratt & Whitney built over half a century ago, the company looked at new engines, including derivatives of business jet and regional aircraft engines, but it concluded that…
