Danger: Airplane Crossing
Controlling airplanes on the ground is a thornier problem than controlling them in the air.
- By Michael Milstein
- Air & Space magazine, August 2007
(Page 4 of 6)
Controllers need AMASS most in bad weather, but the system mistakes rain showers for airplanes. At John F. Kennedy International Airport in New York City, controllers disabled the system one night in July 2005 because of downpours. An Israel Air 767 missed a turn and taxied in front of a departing DC-8 freighter. The freighter pilot later guessed his airplane’s tail came within 45 feet of the 767.
Investigators concluded the system works backward. Making pilots depend on controllers for warnings is like driving a car while waiting for a cell phone call that tells you to watch out for a truck you cannot see, the Department of Transportation’s inspector general, Kenneth Mead, told Congress five years ago. “The very slow pace of fielding technology, the failure to move forward expeditiously with promising new technology, is a major part of the problem and, hence, must be focused on as a major part of the solution,” Mead said.
The FAA also backed research by NASA into a concept that is called “synthetic vision”: a virtual view out the cockpit window that shows pilots everything they wish they could see, but can’t. It’s computer-generated and projected onto a glass screen in front of the windshield. The screen is called a “head-up display” because pilots look straight ahead to view it. Even when thick fog or darkness obscures the view outside, the bright outlines of runways and—with the most advanced technology—the locations of other airplanes appear.
NASA demonstrated synthetic vision aboard a Boeing 757, along with a separate cockpit screen that showed the airplane’s location against a moving map of the airport. Electronic links with the control tower relayed the airplane’s taxi route and the location of other airplanes, so they showed up on the map too. Test flights at Dallas/Fort Worth International Airport in 2000, using a van to simulate another airplane intruding on the runway, found the onboard system alerted pilots to problems 10 to 20 seconds before controllers were aware.
In NASA simulations, the same airline pilots who made wrong turns and other mistakes taxiing through the Chicago airport in low visibility made no errors when they had the displays in their cockpit.
Current head-up display systems, however, do not carry enough airport details to guide pilots beyond the runway. Rockwell Collins began searching about five years ago for airline backing to develop its Surface Guidance System at a likely cost of several million dollars—the final cost will depend on what sort of aircraft the system is being developed for and what other avionics are already on board.
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?’ ”