Restrictions on a $550 million system to prevent runway collisions are compromising safety by keeping the system from accurately tracking snowplows, firetrucks and other ground vehicles at most airports, according to government data and air-traffic controllers.
The National Transportation Safety Board (NTSB) says the risks of a crash on the ground represent the greatest threat in aviation, and the potential for a plane to strike one of the vehicles that crowd commercial airports is a significant part of the problem.
Collisions between vehicles and planes were narrowly averted 26 times from 2003 through January, according to a USA TODAY review of Federal Aviation Administration (FAA) data. That represents 22% of all serious runway incidents, or about one serious incident every other month.
The new system is known as Airport Surface Detection Equipment Model X. It allows controllers, who may not be able to see runways at night or in bad weather, to monitor the location of aircraft on color computer displays in the tower. The system has been hailed by the government and safety advocates as a major improvement over previous technology because it can track aircraft on the ground in all weather.
However, the FAA is blocking the system's ability to track ground vehicles, the agency acknowledges. Because the FAA won't allow those vehicles to carry radio identification beacons, the system has difficulty tracking them, particularly during heavy rain.
The agency is worried that the beacons -- known as transponders -- could interfere with broadcasts from similar beacons on planes. That could cause planes to disappear from radar screens or trigger other safety problems, spokeswoman Laura Brown said. The agency is moving slowly because it wants to avoid unanticipated problems, Brown said.
Controllers at several airports with the new system believe the government's decision undermines safety and is unnecessary, said Brad Rosenthal, local president of the National Air Traffic Controllers Association at Lambert-St. Louis International Airport.
Rosenthal and others say airports that tested the runway system, including Milwaukee and Providence, have beacons on ground vehicles, and the system has functioned well. Similar systems being installed in Europe and Asia include beacons for ground vehicles.
The FAA switched on the system last year at Hartsfield-Jackson Atlanta International Airport, the world's busiest, but not one of the airport's fleet of 1,500 ground vehicles has a radio beacon, said Gary Brittain, local president of controllers.
"It's just amazing to me that they don't have transponders on these vehicles," Brittain said. "I don't know how they justify that. I have a feeling they are making a safety decision based on dollars instead of sense."
Brown said the FAA believes that, in spite of the difficulty with ground vehicles, the system is a significant overall improvement on previous runway safety equipment. Runway safety is a top priority at the agency, which has spent nearly $1 billion on improvements over the past decade, she said. The agency hopes to require beacons on ground vehicles as it scraps radars and moves to satellite-based technology, she said.
Eight airports now have the runway system, including Seattle, Orlando and St. Louis. It will be installed at an additional 27 airports, including all of the USA's largest, over the next several years.
The system was originally intended for smaller airports, but its color displays and advantages in bad weather persuaded the FAA to install it at larger ones.
The NTSB considers runway collisions a top priority. "We've been running on luck too long, and that's no way to run an aviation system," NTSB Chairman Mark Rosenker said at a forum last month.