NTSB Press Release

National Transportation Safety Board
Office of Public Affairs


JANUARY 23, 1996

(Washington, DC) -- Concerned by recent malfunctions in aging air traffic computers, ground-to-air communications problems, and electric power outages, the National Transportation Safety Board said today that the airways are safe because of emergency backup systems and the infrequency of the problems. However, it said resulting flight delays have had "significant economic impact."

The Board said air traffic controllers needed greater proficiency in operating emergency backup computers and it urged the Federal Aviation Administration to develop hands-on training for all controllers. It also recommended that the FAA develop incentives to retain the dwindling ranks of technicians needed to maintain the antiquated computers in use until the agency's delayed modernization program is fully implemented by 1999.

The Safety Board said the communications and power generating breakdowns, which are separate from problems involving the aging IBM 9020E computers, appeared to pose the greatest threat to safety.

It said the FAA's modernization program was designed to address the power generation problem through the use of new design technology. In the third problem area, the NTSB said the FAA should better identify and address the communications deficiencies likely to remain after the modernization program's completion.

The Board's views were contained in a special investigative report undertaken in response to concern over recent outages and disruptions in the air traffic control (ATC) system. Specifically, the concern was initially over outages in the antiquated 9020E computers, but the Safety Board found anomolies with communications and power generation to be potentially more troubling.

The NTSB report noted that the ATC system handles over 220 millon flight operations annually. Of this, some 250,000 are delayed, with less than 2 percent being ATC equipment related, and most others due to weather, according to the FAA.

The Board's report focused on five Air Route Traffic Control Centers (ARTCC's) -- Washington, Ft. Worth, Cleveland, New York and Chicago -- of the 20 in the contiguous U.S. Interviews were conducted with more than two dozen managers and over 50 controllers at these five facitilies. The five operate 30-plus-year-old IBM 9020E computers that are hard to maintain, while the remaining 15 operate Raytheon 750 computers that are about 25 years old. The Board limited its investigation because of time and resources.

The report found that the IBM 9020E outages are "becoming more frequent" and exacerbated by the lack of spare parts as well as qualified technicians, who are taking retirement. It also said some of the 9020E systems are "increasingly likely" to be operated with "compromised" backup systems, increasing technician workloads and risks of outages.

Potential changes in the civil service retirement system will hasten the departure of the technicians, worsening the situation, said the report, but the FAA is offering technician training and has hired additional IBM 9020E experts, "which should minimize the number and duration of the display computer outages.".

The NTSB's report acknowledged that the equipment malfunctions caused serious delays for passengers and economic impact on the aviation industry. It said, "Despite the issues discussed in this report, the Safety Board believes that the U.S. ATC system is very safe and the public should not be unduly alarmed by recent press accounts of specific ARTCC equipment malfunctions.

"In the vast majority of computer outages that have recently occurred, controllers were able to provide safe aircraft separation using a backup system similar to the primary system. On those rare occasions that computer capabilities were degraded further, controllers were able to reroute planes and prevent aircraft departures."

The Safety Board's complete printed report, PB-96-917001, will be available in about a month. It may be purchased from the National Technical Information Service, 5285 Port Royal Rd., Springfield, VA 22161, (703) 487-4650.

Media contact: NTSB Office of Public Affairs
(202) 314-6100



The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.