GAO: Aging ATC system at risk

The Federal Aviation Administration's critical but antiquated air traffic control system could threaten air traffic because it has failed many times, and fixing the system will be challenging, according to the General Accounting Office.

Air traffic controllers use the so-called host computer system (HCS), which was installed by IBM Corp. at 20 en route centers nationwide, to direct aircraft flying over the country and during approach to some airports. The system is important because, among other things, it processes radar surveillance data and flight plans, links the filed flight plans with actual flight paths and provides alerts to potential conflicts.

In a May 1 letter to Rep. Steve Horn (R-Calif.), GAO noted that for the last three years HCS has not operated satisfactorily due to unscheduled outages. Of the 29 unscheduled outages in 1997, 34.5 percent were due to software, 27.6 percent were due to hardware, and 37.9 percent were due to other reasons such as weather, according to GAO.

The outages are likely to increase because of a shortage of critical spare parts. For example, the FAA expects the main processor to reach its end-of-service date by Sept. 30, and prime HCS contractor Lockheed Martin Corp. said last year that it could not guarantee the availability of spare parts for the processor. The FAA is responsible for furnishing any spare parts once the end-of-service date is reached.

As a result, the FAA predicts it will encounter longer system outage times, thereby "reducing the availability of en route automation systems and threatening air traffic services," GAO said.

Lockheed Martin declined to comment.

If HCS fails, there are two levels of backup for controllers, according to the FAA. A host computer redundant system is automatically activated, and an independent radar display system is immediately available. HCS system outages have "not had a detrimental impact on passenger safety, and the new processors that the FAA is installing will have greater reliability," the FAA said in a written response to questions.

Meanwhile, the Year 2000 computer problem poses a serious threat. The HCS processor's microcode, which is low-level machine instructions, will probably malfunction after Dec. 31, 1999, according to IBM. "If there are date dependencies in the processor's micro-

code, HCS could malfunction or shut down, thereby forcing the FAA to operate with the degraded flight processing capabilities provided by its backup system," GAO said.

IBM recommended that the FAA purchase new HCS hardware, which the agency said it will do by October 1999. Lockheed Martin has already started work on the host replacement— without government funding— under its existing host computer contract. The FAA expects the statement of work for the HCS replacement program to be finalized within the next six months. The FAA estimates that the cost to replace HCS will be $607 million, and work would be completed in 2008.

While GAO agreed the FAA "must act quickly" to resolve the HCS problems, risks remain. GAO concluded that the FAA will find it difficult to deploy new hardware to 20 en route centers in less than two years.

In addition, the FAA will find it difficult to deploy a new HCS at the same time it plans to undertake the Display System Replacement program, which replaces hardware, software and controller workstations at en route centers.

To reduce the risk of building the new system, the FAA said it plans to phase in the HCS replacement, deploying new hardware first and then installing new software and peripherals. Meanwhile, the Transportation Department's inspector general plans to review the cost, schedule and risks associated with the HCS replacement, as well as the plans to concurrently deploy HCS and DSR.