UPDATE 2-U.S. FAA directive enshrines changes to Boeing 787 Dreamliner

(Adds details on Dreamliner aircraft, paragraphs 3-6)

By Eric M. Johnson

SEATTLE, May 1 (Reuters) - The U.S. Federal Aviation Administration on Wednesday said it was mandating new flight control software and parts to Boeing Co's 787 Dreamliner to address what it called an unsafe operating condition of certain products on the plane.

The FAA's airworthiness directive to plane operators makes compulsory changes Boeing outlined in service bulletins in 2017 and early 2018 for certain areas in 787's tire and wheel "threat zones" that may be susceptible to damage, the company said.

Boeing's carbon composite 787, of which there are nearly 800 in service, mostly competes with European rival Airbus' A350. These widebody planes represent hundreds of billions of dollars in sales over 20 years.

"This issue has been long since resolved with system improvements that have been incorporated into production for all 787 models," Boeing said by e-mail.

The FAA said damage to the 787's tire and wheel "threat zones" could result in the loss of braking and steering power on the ground at certain speeds.

The FAA said it requires installing hydraulic tubing, a pressure-operated check valve and new flight control software.

The work has been completed on existing 787s and incorporated into the manufacturing process, Boeing said. (Reporting by Eric M. Johnson in Seattle; editing by James Dalgleish and Cynthia Osterman)