Heat found to be cause of F-35 engine blade crack

EAST HARTFORD, Conn. (AP) — Jet engine maker Pratt & Whitney says heat was the cause of a cracked blade on an engine outfitting the U.S. military's F-35 fighter jet.

Bennett Croswell, president of the company's military engines division, said on a conference call Wednesday that finding the cause was "very good news." He said heat is preferable to the effects of fatigue on the engine part because fatigue spreads, making the problem worse.

What Croswell called "thermal creep" was due to the engine operating longer than usual at a high temperature. He says it was the only affected engine of about 75.

The Pentagon briefly grounded its fleet of F-35 fighter jets on Feb. 22 after discovering the cracked engine blade at Edwards Air Force Base in California.

Pratt & Whitney, based in East Hartford, Conn., is a subsidiary of United Technologies Corp.