FAA BLAMES UPKEEP LAPSE RADIO FAILURES LED TO SEVERAL NEAR-COLLISIONS.

Byline: Charles F. Bostwick Staff Writer

PALMDALE - Three pairs of jets came close enough to set off cockpit alarms after air traffic communications shut down because of the failure to do routine maintenance on a radio system, officials said Wednesday.

Two more pairs of planes got close enough to violate Federal Aviation Administration separation standards in the first 13 minutes after Tuesday's three-hour communication breakdown at a Palmdale control center, which FAA officials said resulted from a maintenance lapse.

``It was very dangerous,'' National Air Traffic Controllers Association official Mark Sherry said Wednesday of the communication breakdown. ``This is as ugly as it gets, short of running two airplanes together. We could have had 10 airplanes go down.''

FAA officials said none of the incidents equated to a near-mid-air collision. They added that airplanes will be allowed to fly that close after Jan. 1 because American standards are changing to match international ones.

``A loss of communication is a serious matter and should never have occurred. We take it seriously,'' said Rick Day, the FAA's vice president for en-route and oceanic traffic control.

FAA officials said they were modifying communications systems nationwide to prevent further failures, as well as trying to find out why the maintenance was not performed and why the backup system was not configured properly to take over.

Stranding tens of thousands of travelers and forcing hundreds of planes to be rerouted, the air traffic breakdown occurred after a problem in a computerized radio system by which controllers in the Los Angeles Air Route Traffic Control Center in Palmdale talk to pilots and other control centers.

A technician switched to the backup communication system, but it failed after about a minute, officials said.

Within minutes, a Northwest 757 traveling at 35,000 feet from Detroit to San Diego came within 0.9 miles and 900 feet vertical separation from a Gulfstream III business jet climbing out of Long Beach, controllers said.

FAA officials said the planes were 1,400 feet apart vertically.

A UPS 757 heading to Orange County from Louisville, Ky., at 35,000 feet came within 1.9 miles and 1,000 feet vertical separation from a Cessna Citation business jet heading out of Phoenix, controllers said. The FAA said the planes were 1,100 feet apart vertically.

FAA regulations now require planes higher than 29,000 feet to be at least 2,000 feet apart vertically or five nautical miles - 5.75 standard miles - apart horizontally. That will change Jan. 1 to at least 1,000 feet vertical separation, the same standard as below 29,000 feet.

The other aircraft were not identified.

Within minutes of the breakdown, the 400 aircraft being tracked by the Palmdale center were taken over by centers in Denver, Albuquerque and Oakland, as well as the Phoenix airport tower and Southern California's radar approach and takeoff control center in San Diego, FAA officials said.

The FAA said the failure occurred after a monthly maintenance procedure instituted nationwide last year after a less-disruptive communication failure in Atlanta was inexplicably not performed, and the backup system was not configured to take over properly.

``There were no software glitches, there was no component failure. There was human error. We failed to do the maintenance,'' FAA chief spokesman Greg Martin said Wednesday.

Revised software was developed and tested after the Atlanta failure, has been installed in Seattle and is being installed nationwide, officials said. Similar failures have occurred in Houston and elsewhere, but in all those the backup communication system worked, officials said.

After Tuesday night's failure, the FAA rechecked each of its air route centers to make sure that the monthly maintenance procedure - called a ``buffer purge,'' and equated to rebooting a computer processor - was being followed.

While the communication system is about seven years old, the new procedure was instituted after an upgrade about two years ago to replace an older computer that grew too old to get parts for, said Steven Michaleski, the Palmdale spokesman for the union representing maintenance technicians.

``We believe the reason that hadn't got done during maintenance was because the person doing the maintenance hadn't been trained,'' said Ray Baggert, a regional officer of the Professional Airways Systems Specialists, the technicians union. ``We have such short staff they can't get people out to get training.''

FAA spokesman Martin said the procedure that was not done was a routine one that is spelled out in maintenance manuals.

Sherry, the controllers union official, scoffed at the FAA's explanation that the distances between the planes were ones that will be allowed after Jan. 1, saying that controllers who allow such a thing to happen now would be demoted or fired.

``Were we safe when nobody could talk to 400 airplanes at 500 mph each? I don't think so,'' Sherry said.

He also dismissed blaming the breakdown on a maintenance failure, asking why the backup went out.

``You're going to blame some poor schmuck for not doing the maintenance?'' he asked.

Air route centers like the one in Palmdale control airliners and other planes as they fly from airport to airport. They give pilots instructions, air traffic clearances, and advice regarding flight conditions, and keep the planes flying at safe distances.

Controllers hand off direction of aircraft to controllers in adjacent centers, or to approach control centers. Airport towers take over control a few miles from the airport.

Charles F. Bostwick, [phone]

chuck.bostwick(at)dailynews.com