Pilots sometimes refer to travel between the runway and an airplane’s parking spot as “the forgotten phase of flight”—and many consider it the most demanding. Sweeping tarmac disappears into the horizon, especially at night, when airfields become a sea of blue taxiway lights. Sophisticated instruments that help pilots navigate in the air offer scant help on the ground, leaving air crews to find their way with little more than paper maps. Pilots must combine what they see out the window with their map of the airport to figure out where they are, at the same time they’re communicating with their airline and ground control and maneuvering the airplane. “There are points when [successful communication] doesn’t happen, and that’s how we end up with incursions,” says Rick Shay, a United Airlines pilot. Experts call the lapses “loss of situational awareness.”
While high-end automobiles now carry color electronic maps that display the car’s location on roads and highways, “we don’t have that in our cockpits,” says Terry McVenes, a US Airways captain who leads safety efforts for the Air Line Pilots Association.
David Foyle, who studies incursions at NASA’s Ames Research Center in California, recalls sitting with two pilots in the cockpit of a NASA Boeing 757 at a three-way intersection at Atlanta’s Hartsfield-Jackson International Airport a few years ago. The pilots couldn’t agree on which way to go. “They stopped the airplane and they started arguing about it,” Foyle says. The airplane was already past signs for the intersection, and the pilots had no way to tell on their own where they were. It turned out neither pilot was right.
It doesn’t help that many busy airports were not designed for today’s booming air traffic, says Paul Erway, the FAA’s acting director of runway safety. As incursions multiplied, the FAA increased training for controllers and launched campaigns to educate pilots. That has helped, says Erway. What’s left are a stubborn few errors that may never be eliminated as long as people are involved.
“Because we’re human, we’re going to make mistakes,” he says. “What we’re looking at now is modifying the system so the inevitable human error doesn’t result in catastrophe.”
Los Angeles International Airport has recorded more than 40 runway incursions since 2001. The cramped airport layout, dating to the 1950s, forces airplanes to cross two inner runways and two parallel outer runways to go between terminals. Aircraft cut across the inner runways roughly 900 times a day. Twice last year, controllers told pilots to stop before crossing and heard the pilots repeat the instructions back, only to see the pilots go across the runway anyway—into the paths of airplanes that were taking off. Almost every day, says Michael Foote, an air traffic controller at LAX, at least one pilot does not follow his instructions.
In one incident, the pilot of a departing commuter jet can be heard on air traffic control tapes gasping for breath after a British Gulfstream jet crossed in front of him, forcing him to jam on the brakes, even though controllers twice told the Gulfstream not to proceed. The commuter’s brakes took 40 minutes to cool down.
The risk of collisions rises roughly twice as fast as the growth in air traffic, according to Arnold Barnett, a professor at the Massachusetts Institute of Technology’s Sloan School of Management. That’s because as more airplanes travel through airports, risk rises in two ways. First, more aircraft are likely to stray into the wrong place. Second, more airplanes make it more likely a straying aircraft will collide with another one. The top 32 busiest U.S. airports already log about twice as many close calls as others.
Based on FAA projections of increases in air traffic, Barnett calculates that, if nothing is done, by the early 2020s, U.S. airports could experience about 15 fatal accidents, killing as many as 700 to 800 people. The low number of major accidents so far indicates that for airplanes to hit each other, errors must happen at precisely the wrong time—and that’s rare. “Not only do people have to make mistakes, but you also have to have really bad luck for a collision to occur,” Barnett says.
Catastrophes have already struck. On a foggy runway on Tenerife, one of the Canary Islands, in 1977, the pilot of a KLM Boeing 747 apparently misunderstood air traffic control instructions and accelerated into a Pan Am 747 taxiing along the airport’s single runway. Everyone on the KLM jumbo and most on the Pan Am airplane died—583 in all.