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Communications of the ACM

Communications of the ACM

Are We Ready?: The FAA's Y2K Preparedness

Over the last few years, media attention has focused on the Y2K computer problem and potential disasters that it may cause. Computer systems worldwide may encounter problems ranging from slight anomalies, such as time tracking and problem reporting, to total system failures. Electrical power grid failures, elevator and security system interruptions, and airline crashes have been prophesied.

The Federal Aviation Administration has been aggressive in addressing the concerns that the U.S. air traffic control system would cease to work as the clocks rollover on New Year's Eve. The FAA has shed its old mentality and developed a new paradigm to make up for lost time and planning. After extensive testing, the FAA can say with confidence that the U.S. air traffic control system will be fully operational well into the new millennium.

In order to understand the complexity of the problems facing the FAA, we must examine and understand the operation of the Air Traffic Control System (ATCS) and the Air Route Traffic Control Center (ARTCC).

The ARTCC is made up of tracking stations that monitor and track all air travel around the U.S. Currently, 20 such centers are in operation. Through radar and other communications, information on each aircraft's altitude, speed, heading, type, and airline/owner is monitored. The ARTCCs manage air traffic between airports and within the National Airspace System (NAS). Airport control towers manage local air traffic, including but not limited to, takeoffs, landings, and taxiing.

Today, the overall management of U.S. airspace, the identity of each aircraft, as well as the safety of the passengers, is the responsibility of this system, created in the 1960s. The system relies heavily on instantaneous communications between pilots and air traffic controllers, as well as automated systems, in a network that is nearly 40 years old.

The mainframe computers acting as the central computers, or hosts, for most of the ARTCC systems—IBM 3083s, IBM 9020Es, IBM ES/9121s, and the Raytheon 750—are antiquated vacuum tube systems. Complicating matters for the FAA is the fact that these systems are water-cooled. IBM and others have warned that hardware and code that handle the water pumps cooling the tubes, processors, and wiring will fail due to Y2K noncompliance.

Additionally, when the software managing the communications for the national aviation system was written, programmers truncated certain fields, such as the date fields, in order to save space and time. By omitting the first two of the four digits in the YEAR date field (YYYY), they didn't anticipate that many computers would interpret this truncated field on January 1, 2000, as January 1, 1900, thereby possibly causing a variety of system errors and miscalculations. They assumed their code would be replaced well before the new millennium.

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The FAA's Approach to Y2K-Compliance

As of June 1999, the FAA reported all of its mission and non-mission critical systems fully Y2K-compliant. These systems underwent a detailed system documentation review as part of an independent validation and verification (IV&V) process conducted by an outside contractor. The Department of Transportation's Office of the Inspector General and the General Accounting Office examined a sample set of systems and approved the FAA's work. The host system has been fully renovated and exhaustive testing has been unable to identify any microcode Y2K computer problems with the operational processing of flight and radar data

As a contingency plan for Host micro-code purposes, the verification team initiated, developed, and tested a rollback strategy and found the setback tests indicated that the logic built into the micro-code contain no year-specific processing checks. The FAA continues to conduct this contingency testing with the FAA's host maintenance contractor. In addition to making the current legacy systems Y2K compliant, the old legacy systems have been replaced with new IBM G3 systems. The FAA Y2K Office confirmed that replacement of the host system at all sites was completed in October 1999. If for some unforeseeable reason they fail to function, the old host Y2K-modified systems will provide redundancy and back-up for FAA operations. In the unlikely event the new IBM G3 systems fail and the current legacy systems fail, the FAA can rely on a system known as Direct Access Radar Control (DARC). If DARC fails, air traffic controllers can resort to manual control of airspace.

Work has been so successful that as the year rolls over, the FAA administrator and senior staff are flying commercially from Washington to San Francisco.

The FAA has also followed the GAO guidelines, published in the Year 2000 Computing Crisis: An Assessment Guide very closely. The FAA included Department of Defense and aviation industry representatives as part of its Capacity Impact Team to evaluate Y2K computer risks to the NAS. Part of this contingency plan also includes involving unions representing controllers and technicians, such as the National Air Traffic Controllers Association, the Professional Airways Systems Specialists, and the National Association of Air Traffic Specialists in collaborative decision-making workshops.

The FAA has also engaged several partners, including contractors, to help manage the Y2K-compliance program. The FAA's Program Office is responsible for all of the FAA's Y2K remediation efforts and established the following four goals for the agency:

  • Ensuring the NAS and all other core FAA systems will operate reliably through 2000 and beyond,
  • Ensuring all lines of business across the FAA follow a consistent approach and adhere to the project schedule,
  • Monitoring the status of all FAA Y2K efforts throughout the entire repair life cycle, and
  • Minimizing risk associated with the FAA Y2K repair efforts.

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Despite what are widely viewed as insurmountable odds, the FAA claims it has thus far been successful in ensuring all of its systems are Y2K-compliant, guaranteeing air travel during the transition from 1999 to 2000 is not disrupted. As an organization of contingencies, the FAA has in place redundant systems should the unforeseen problem occur in either the hardware or software managing national air space. Quality control, independent testing, and validation have been implemented and maintained throughout the process. Their work has been so successful that as the year rolls over, the FAA administrator and senior staff are flying commercially from Washington to San Francisco, with a short stop in Dallas, to prove to the traveling public that the systems they rely on will work as expected.

Finally, other countries have noted the FAA's dedication to the compliance cause. The FAA has been asked to lead a panel convened to assess the Y2K compatibility of other countries. The FAA has been working extensively with the International Civil Aviation Organization in Montreal, to assist member nations in achieving Y2K system compliance, and in developing contingency plans of their own.

The traveling public depends on the complex systems that allow so many planes to fly over U.S. airspace routinely and without incident. In a very short period of time, the FAA has been able to break the old bureaucratic paradigm, create a new streamlined paradigm, and take the necessary steps of remediation and contingency planning. The FAA should be commended for taking the bull by its horns and making Y2K- compliance happen.

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Frank Cuccias ( is a member of the adjunct faculty at Averett College, Danville, Va.

©1999 ACM  0002-0782/99/1200  $5.00

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Chris Bigos

"The mainframe computers acting as the central computers, or hosts, for most of the ARTCC systems IBM 3083s, IBM 9020Es, IBM ES/9121s, and the Raytheon 750 are antiquated vacuum tube systems". No they are not. What a ridiculous statement.

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