Danger: Airplane Crossing

Controlling airplanes on the ground is a thornier problem than controlling them in the air.

Who's at fault when airplanes cross paths where they're not supposed to? Controllers, pilots, and even the Federal Aviation Administration share the blame. (Paul Dimare)
Air & Space Magazine | Subscribe

(Continued from page 3)

The goal was to translate NASA’s demonstrations into commercial reality. The vision was grand: Pilots would see taxi routes projected onto the screen in front of them, advising them how to adjust their speed to make the next turn. Traffic cones would pop up across their paths when they approached a runway they should not cross. But then came September 11, 2001, and suddenly airlines were more focused on survival than investment.

“Everybody thought it was a great idea, but there was no money to develop it,” says Peter Howells, the main system engineer at Rockwell Collins. The other problem, he adds, is that while everyone is concerned about incursions, many airlines see it as a problem caused by the mistakes of other pilots. “They say, ‘It’s not us that has the problem. It’s those other people. Why should we invest in this equipment when it’s the others causing the issue and we’re essentially the victims?’ ”

NASA’s Foyle and Becky Hooey, a San Jose State University researcher based at the Ames center, found a good reason for such investment when they studied the performance of pilots in NASA simulators. Advanced displays reduced pilots’ workload; a moving map helped plot their route, and a head-up display helped them plan upcoming turns. They taxied faster and reached the gate sooner. Rockwell calculates the extra speed would enable a 737 carrying about 150 people to earn another $35,000 to $50,000 a year. That payback will probably drive what airlines will spend on the system, Howells says. But FAA leaders and others caution that an elaborate new system does little good if airlines cannot afford to install it in their airplanes. While new-generation aircraft will likely carry head-up displays as standard equipment, it’s difficult for airlines to make a good business case for installing the displays purely in the interest of runway safety, says Barimo of the Air Transport Association.

As a backbone of its strategy to handle traffic in ever-busier skies, the FAA is now investing heavily in ADS-B, a system that provides more precise air traffic data (see “How Things Work: Aircraft Identification,” Oct./Nov. 2006). The system will help prevent runway incursions too, making it easier for controllers and pilots to see the location of aircraft on runway maps. But it will cost close to $7 billion—with the price split among the FAA, airlines, and others—and will not be completely finished until 2035.

“This is a very important area to us,” FAA spokesperson Laura Brown says. “But we have a lot of other technologies we’re working on, and they always compete for funding.”
There is also a resistance to filling cockpits with gadgets, both because of cost and because no one wants to distract pilots, says Robert Francis, a longtime FAA official who later served on the NTSB. And any new equipment for airplanes must be foolproof before it can be put in place.

“The real challenge is: How do you balance the need to be responsive with the need to be so careful and so precise?” says former FAA administrator Garvey. “The degree of precision in navigating a car is very different than what you have to have in aviation.”
Controllers are getting an important new tool as well: a new ground radar system known as Airport Surface Detection Equipment, Model X. It provides an all-weather view of the airport by combining radar signals with data from airplane transponders. An electronic airport map labels each aircraft on the screen so controllers know which is which. But it, too, is behind schedule, because of funding problems, and will not be in place at 35 leading airports until 2011.

One bright winter day, Markus Johnson, chief test pilot for Honeywell Aerospace, lines up his Beechcraft King Air for takeoff from Salem, Oregon. The sun glares in his eyes, but he’s on the right heading to depart from Runway 16. He guns the engines and the airplane rolls faster. Suddenly, on his headset, he hears an urgent voice: “On taxiway! On taxiway!”
His airplane carries Honeywell’s Runway Awareness and Advisory System, an inexpensive (less than $20,000) software upgrade to a common system that warns pilots when they approach dangerous terrain. It contains electronic airport maps and closely monitors the airplane’s direction and speed. Six airlines have already installed it.

“There are a million different reasons why pilots lose track of their position,” Johnson says. “What we want is RAAS to be this third guy in the cockpit who’s just watching and is going to tap you on the shoulder and say, ‘Here’s where you are.’ If you agree with that, that’s great. If you don’t agree with that, you say, ‘Let’s stop and see what’s wrong.’ ”

For pilots of a Comair commuter jet that took off from the wrong runway in Lexington, Kentucky, last August, the runway awareness system would have given three key warnings they were off course: when they approached, when they lined up, and again when the system recognized the runway was too short for their jet to take off from. As it was, the pilots didn’t realize that until they were beyond the point where they could abort their takeoff; 49 of 50 people aboard were killed.

At San Diego’s Lindbergh Field, the busiest single-runway commercial airport in the nation, the runway is sacrosanct. “Our dependency on the use of that runway is absolute,” says Ted Sexton, vice president at the airport and a former Navy pilot. Airplanes scream in and out less than two minutes apart on average, so if anyone happens to stray onto the runway, “someone gets hit in two minutes.”

Comment on this Story

comments powered by Disqus