GRAPEVINE, Texas -- As American Airlines Flight 629 rolled slowly onto the runway for departure one recent morning, it entered one of aviation's most dangerous places.
Many of the worst aviation disasters around the world have occurred on runways. Despite repeated attempts to reduce the risks, near-collisions happen in alarming numbers throughout the USA.
But on this particular day at Dallas/Fort Worth International Airport, the pilots of the American MD-82 had the benefit of a safety system being tested that for the first time warns pilots directly of runway perils.
As Flight 629 waited for takeoff clearance from controllers, a brilliant string of red lights embedded in the runway lit up because two other jets were crossing farther down the runway. If there was any misunderstanding, the red lights made it clear that Flight 629 did not yet have permission to take off.
After a year of tests at one of the nation's busiest airports, officials with the Federal Aviation Administration (FAA) are optimistic that the runway status light system can be approved for use at busy airports around the country.
In the world of aviation, where new systems frequently run into problems and face criticism from users, the runway lights have received near-unanimous support from safety advocates, pilots and air-traffic controllers.
"It's a great system," says Capt. Jack Eppert, a regional safety coordinator for the Air Line Pilots Association. The pilots at American, which dominates the airport here, also endorse it, says Capt. Bill Mino, a safety chairman at the Allied Pilots Association.
Mark Rosenker, acting chairman of the National Transportation Safety Board, says the system appears to fulfill one of the agency's long-standing recommendations that pilots be given better warnings of potential hazards on runways. "It's one of the most important issues to us," Rosenker says.
The money-strapped FAA has not committed to fund the system, but Administrator Marion Blakey says she is encouraged by early results. Blakey, who headed the accident investigators at the NTSB before becoming the chief aviation regulator at the FAA in 2002, has made runway safety a priority. She calls the system "very promising."
On March 27, 1977, the pilots of a KLM Boeing 747 carrying 248 people sped down a fog-enshrouded Canary Islands runway after mistakenly thinking they had permission to take off.
The pilots did not realize that a Pan Am 747 carrying 396 people was taxiing in the opposite direction on the same runway. The two jets slammed into each other at more than 100 mph.
The fiery collision killed everyone aboard the KLM jet and 326 on the Pan Am flight, a total of 574. The accident remains the worst in the history of commercial aviation.
In the nearly 30 years since the accident, new technologies and training have dramatically lowered accident rates. Entire categories of risk, such as midair collisions and wind-shear crashes, have been virtually eliminated. The complex mix of human failures that cause runway collisions, however, remains.
At least 76 people have died in three runway collision accidents involving commercial aircraft in the USA since 1990. More than 300 incidents a year occur on runways in this country; 30 to 50 of those are categorized as most risky, according to the FAA.
Such incidents, in which FAA investigators have determined that there was a significant risk of collision, have declined since 2000, but enough occur each year that the NTSB considers the issue one of aviation's top safety priorities.
Last month at Chicago's O'Hare International Airport, three runway incidents were reported, including one that investigators considered severe. Another near-collision in Chicago in 1999 -- in which two 747s came within 75 feet of a high-speed collision -- prompted the NTSB to recommend a better runway warning system.
Quest to warn pilots
Current warning systems alert controllers, not pilots, if planes get too close on runways. NTSB investigators have found that the warnings are better than nothing, but they leave much to be desired.
The quest for a way to warn pilots directly goes back to the early 1990s. Scientists at MIT Lincoln Laboratory experimented with runway warning lights at Boston's Logan International Airport. The system did not work well because it was difficult to track planes on the ground with radar, says Jim Eggert, who is the laboratory's project leader in Dallas.
In the ensuing decade, however, the technology to monitor aircraft on the ground improved exponentially. Computers can follow planes with great precision. The system was revived in Dallas, where airport officials had spent $6.4 million on a state-of-the-art system to track taxiing aircraft.
Controllers are still in charge of choreographing departures and arrivals. Richard Loewen, who heads the National Air Traffic Controllers Association's Dallas tower branch, says controllers appreciate the fact that the lights provide additional safety without slowing traffic.
If there is a downside to the system, according to Loewen and others, it is that it may take several years to receive final permission and funding from the FAA.
The basis for the system, computers that track planes on the ground, was supposed to be put into 35 airports, but budget shortfalls have slowed its deployment.
Loewen says air-traffic controllers don't understand why it's taking so long. Those who work in a tower on the other side of the airport, where the lights are not in operation, want the system installed there, too, he says.
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