Software snag grounds L.A. flights

Air traffic controllers had to ground hundreds of flights headed for Los

Angeles International Airport Thursday morning after new software loaded

overnight crashed the main computer system.

Controllers at Los Angeles Air Route Traffic Control Center reverted

to a manual backup computer system to monitor air traffic coming into LAX

after they discovered at 6:58 a.m. EDT that new software had shut down the

host computer system, an FAA spokesman said.

The host system is the base for the modernization of the nation's 20

air route traffic control centers. It processes radar surveillance data

and flight plans, displays it on controllers' screens and provides alerts

of potential conflicts.

The backup system made it more difficult for controllers to hand off

aircraft moving from sector to sector, but controllers still received radar

data, the FAA spokesman said.

Controllers fixed the problem by reloading the old software onto the

host system, the spokesman said.

Service into the Los Angeles airport was partially restored at 11:15

a.m. EDT and fully restored by 1 p.m. EDT. About 84 aircraft normally land

at the airport per hour.

A similar problem in 01/at the Washington Air Route Traffic Control

Center in Leesburg, Va., affected more than 300 flights. In that case, a

manual restart of the host system held up a flight plan from Raleigh-Durham,

N.C., just as it was about to be printed. Because the printer did not respond

to the flight plan, the flight plan got stuck in the buffer and backed up

the transmission of other flight plans to the printer.

The details of the Los Angeles system failure will be investigated.