Computer Outages at Air Terminal Facilities and Their Correlation to Near Mid-Air Collisions

AFMD-82-43: Published: Feb 16, 1982. Publicly Released: Apr 20, 1982.

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GAO surveyed the Federal Aviation Administration's (FAA) Automated Radar Terminal System (ARTS) to determine the extent of computer outages at terminal facilities and whether any correlation existed between near mid-air collisions and computer outages.

GAO found that the computers at the nine terminals surveyed were unexpectedly out of service a total of 202 times during the GAO test periods. The duration of the outages ranged from less than a minute to nearly 10 days. These computer outages, however, did not always result from computer malfunctions. Of the 202 outages, 49 were caused by commercial power interruptions, radar failures, telecommunication breakdowns, and unknown conditions. Although most of the terminal facilities experienced some computer failures, GAO found no direct correlation between the times that the outages occurred and the occurrence of near mid-air collisions. Because terminal facilities are not required to report partial outages to FAA headquarters, FAA does not have the data needed to easily predict when deteriorating equipment needs to be refurbished or replaced. GAO also observed that new computer hardware had been installed and was sitting idle for about 2 years at five of the ARTS terminals reviewed. Completion of the program has been impeded by computer software development problems. The New York Terminal Radar Approach Control facility has unique problems. The ARTS computer does not have sufficient computer capacity to support the five major airports for which it was planned. It also does not have the capacity to handle anticipated traffic increases and does not have an alert feature which would automatically alert controllers of aircraft on a collision course.