A computer system that air traffic controllers rely on fails and radar screens go blank. Error messages flash on computer screens. Controllers scramble for pencil and paper and try to plot where the planes were.
Unknown to controllers, two jumbo jets carrying a total of 372 people are on a collision course 6 miles above the East Coast.
It is not the stuff of made-for-TV movies. It happened. In December. As the planes neared each other, computers on both aircraft alerted crews to the problem.
A week earlier, a similar incident occurred. Two planes came within 300 feet of each other. That time, the on-board computer system brought the planes that close.
Long-range forecasts that call for more airplanes, more flights and more crowded skies make one wonder: How safe is it to fly?
The simple answer is it is very safe–for now.
But there are signs that the air traffic control system is strained to the breaking point, and the accident rate, though low, has plateaued since the last big safety breakthrough of reliable jet engines. If air traffic increases at expected rates and if promised safety measures are not taken–or fail to make the system safer–experts say that within 20 years, we can expect an airline crash every eight to 10 days.
Now, the risk of being in a fatal air crash on a U.S. commercial jet is about one in 3 million.
“With these two (near misses), it was either a TCAS (the on-board computer that warns pilots of approaching airplanes) problem or an ATC (air traffic control) problem, but not both,” says Arnold Barnett, a statistician at the Massachusetts Institute of Technology.
“It seems to me you’d have to have a TCAS failure and an ATC failure, and some very bad luck, to have a midair collision,” he said. “So in some ways, these incidents suggest the margin of safety, rather than it is on the brink of collapse.”
Taking the long view, there is reason for concern about the nation’s air-traffic control system. Unplanned outages of power, computers and radar have been increasing steadily in recent years as equipment is extended well beyond its normal life.
Consider the Boston Center, in Nashua, N.H., where controllers handle high-altitude flights over New England and Upstate New York. Last year, they faced, on average, an outage a day that lasted from a few seconds to more than a half-hour. But when a radar screen loses crucial data, controllers responsible for keeping planes separated have no way of knowing whether it will reappear with the next radar sweep, in 12 seconds or in 12 hours.
And nationwide, in 1983 the total unscheduled downtime for air traffic and navigation equipment was 210,000 hours. In 1997, it was 600,000 hours.
In the early 1980s, the Reagan administration vowed to rebuild the air-traffic control system with new technology. But the Federal Aviation Administration underestimated the cost and complexity. Parts of the system were obsolete before they could be delivered. So equipment that was old in the early 1980s is still being used.
The FAA says it will have to spend at least $42 billion to modernize the air traffic system. Administrator Jane Garvey said modernization is her top priority.
Some new equipment, long-range radar systems, computers and controller displays, are being installed in centers that handle high-altitude traffic; to facilities (called TRACONs) where controllers direct planes when they leave major airports or just before they start final approaches; and to airport towers, which handle arriving and departing planes and those on the ground. But modernization is still a ways off.
Perhaps even more alarming than the old equipment is the shortage of people qualified to fix it. And spare parts can be as hard to come by as a technician.
“We have major facilities across the country that do not have certified people on duty during critical times, and the agency rolls the dice that nothing will occur during those hours,” says Michael Fanfalone, president of the Professional Airways Systems Specialists, the union representing the technicians who maintain and repair computers, radar, power systems and navigation aids. Los Angeles International Airport, he said, does not have technicians on duty 24 hours to repair radar. And in one metropolitan New York facility, technicians are cannibalizing radar displays for parts to keep the system working.
Why the shortages? In large part it is due to the FAA’s failure to modernize the system as it planned nearly 20 years ago. Why keep technicians on, the agency reasoned, if we will have a new automated system? But the new system has not arrived.
Some of the IBM computers used to run air traffic are so old all the engineers who worked on them have retired. The FAA could find only one former IBM official willing to go over millions of lines of code in a mainframe computer used by controllers to see whether the system will be affected by the Year 2000 problem.
Nevertheless, the FAA insists the system remains safe.
While one can argue about how much safety is compromised by old equipment, understaffing and lack of parts, it is irrefutable that those problems slow the system. Planes that would have been in the air are kept on the ground, and those in the air are spaced farther apart. The results are costly delays and cancellations.
A panel appointed by Congress, the National Civil Aviation Review Commission, warned a year ago: “Unless the FAA and various aviation stakeholders–the Congress, the Executive Branch and the aviation community–change the status quo, internal and external to the FAA, our nation’s aviation system will succumb to gridlock. Delays will skyrocket while we reminisce about the reliable flight schedules of the past. This current course will impair our domestic economy, reduce our standing in the global marketplace and result in a long-term deterioration of aviation safety.”
The FAA has big plans, including the use of an enhanced global positioning system to help planes navigate more accurately and enable them to fly from point A to point B without having to follow the sometimes-winding route required by ground-based navigation aids. But the FAA recently had to scale back its vision of the enhanced GPS satellite systems (known as WAAS and LAAS) because of a variety of risks, including cost.
Such “free flight” will take many years, but under phase one, some facilities will receive equipment by 2002 that will let pilots and controllers communicate by airborne e-mail, which should improve communications, and controllers will have better tools to help them identify potential conflicts in flight patterns. Prototypes are in Memphis and Indianapolis.
But long before free flight happens, the FAA is likely to experience problems upgrading computers and radar displays.
The backup system is referred to as DARC. But controllers say they have little experience on DARC. So, there is confusion when the primary system fails.
The Department of Transportation inspector general, in a report released late last year, and the National Transportation Safety Board, in a report released two years ago, agreed with the controllers’ demand for more DARC training. The FAA says the twice-a-year training (much of it video-based) is sufficient, though it does not include using simulated traffic patterns on the computer system.
While Mike McNally, president of the National Air Traffic Controllers Association, applauds many of the technological improvements the FAA is pushing, he says it is imperative controllers get more training in DARC. And McNally said controllers also need refresher training in how to safely separate airplanes when there is no radar.
