Power outage halts flights at Washington DC airport

WASHINGTON Jan 4 (Reuters) - A power outage on Monday temporarily halted flights and security operations at Washington Reagan National Airport, airport officials said.

The midday power failure affected all terminals and departing flights at the suburban Virginia airport across the Potomac River from Washington, D.C. Security screening was halted for about 50 minutes.

It was the second disruption in as many days at a big U.S. airport. On Sunday night, a security breach prompted authorities at Newark airport in New Jersey to evacuate a terminal and rescreen passengers.

Flight delays at Newark over the incident stretched into Monday.

Airports are on heightened alert after a failed attempt to blow up a Detroit-bound jetliner on Dec. 25.

The power failure at Reagan National was located in an airport electrical substation, according to airport spokeswoman Courtney Mickalonis. Dominion Virginia Power, a unit of Dominion Resources (D.N), said it was able to restore service once the source was identified.

The cause of the substation failure was under investigation.

The air traffic control tower lost primary power but was able to function on a backup generator, the Federal Aviation Administration said.

Departures were grounded temporarily with security screening halted. Related delays were expected to continue through the day.

Newark is a hub for Continental Airlines CAL.N while Reagan National is a hub for US Airways (LCC.N).

(Reporting by Jim Wolf and John Crawley in Washington and Scott DiSavino in New York; Editing by Eric Beech)