Study Offers Ways to Cut Crash Risk on LAX Runways
Los Angeles International Airport could reduce its nation-leading pace of near misses on runways if airport operators changed the way controllers direct traffic on the aging airfield, according to a report expected to be released next month.
The new routes for aircraft would require redesigning part of the south side of the facility to limit the number of planes crossing active runways, the first-of-its-kind study concluded.
Airport operators say the findings could provide short-term solutions to the seemingly intractable problem of near misses at LAX, although the fix could make it more difficult to move planes through the already jammed airport.
“The bottom line is we believe LAX is safe,” said Michael DiGirolamo, deputy executive director of airport operations at the facility. “This is an interim step that increases our safety margin within 2 1/2 years.”
This solution, however, doesn’t replace the need for the $12-billion master plan, which would enhance safety at LAX by separating the runways and adding new taxiways that would not cross the runways, DiGirolamo said.
The Federal Aviation Administration and the city agency that operates the airport commissioned the $485,000 study, conducted by NASA as part of a continuing effort to curtail near misses at LAX.
From 1997 to 2000, LAX runways had 13 serious near crashes, the highest number among the nation’s busiest airports, according to the FAA. For the first six months of this year, the airport logged almost twice as many near misses as during the same period last year--although the FAA found that the chance of crashes in those instances was remote.
NASA conducted the study at a facility known as FutureFlight Central at its Ames Research Center in Sunnyvale, Calif. NASA and the FAA designed FutureFlight to allow airports to test operational changes in a virtual tower. LAX is the first airport to use the facility.
“This is risk free, and it’s a very academic way of analyzing traffic flow,” said Sherry Avery, the FAA’s tower manager at LAX. “The study helped to eliminate things we found wouldn’t work at all, and narrowed it down to options that may work.”
Study participants cautioned that the findings are preliminary. In the next few weeks, the FAA will brief the city airport agency on whether the NASA alternatives comply with federal requirements, Avery said.
Airport operators hope the study will finally advance a years-long effort to increase runway safety at LAX. The city agency has spent $5 million since 1999 to install more lighting and signs on taxiways and runways, enlarge markings at the ends of taxiways and distribute posters showing problem spots to pilots.
To complete its study, NASA worked with airport operators, LAX controllers and LAX-based pilots to simulate traffic conditions at the world’s third-busiest airport.
First the group devised a baseline by simulating traffic during peak hours in the virtual tower. The tower features a 360-degree, high-resolution picture of the airfield--giving pilots and controllers the feeling that they were actually working at LAX.
Then two groups of four controllers tested six proposed alternatives. They included placing additional controllers in the tower, changing the way controllers directed traffic, swapping the runways and changing the airfield’s configuration.
Controllers filled out surveys, rating not only the safety implications of each option, but also how it affected coordination among controllers, ground communication with pilots and the efficiency of airfield operations.
NASA also compared each of the six alternatives to the baseline to determine whether it made the airport “safer than LAX today,” “about as safe as LAX today” or “less safe than LAX today.”
Not surprisingly, participants found that adding controllers under the right circumstances helped improve traffic flow and safety. LAX has long had a tough time retaining its full complement of controllers--it is currently 10 short of the 47 fully certified controllers the FAA allots it.
The alternative with the most potential to make LAX safer would require controllers to direct planes on a more roundabout taxiing path, skirting the end of two runways rather than crossing them.
A majority of near misses--known as runway incursions in airline jargon--at LAX in the last four years occurred on taxiways crossing runways on the south side of the airfield.
“This option eliminated one of the main causes of runway incursions--which is runway crossings,” said Nancy S. Dorighi, manager of FutureFlight Central.
But to complete the new route, the city airport agency would need to extend the south taxiway so that it completely bypasses the west end of the runways and connects with the road encircling the terminals.
Increased traffic on the taxiway could increase complaints from El Segundo, where neighbors have been vocal opponents of airport expansion.
“There’s a very fine line here,” said El Segundo Mayor Mike Gordon, a key organizer of anti-expansion forces. “If expansion of that taxiway occurs, it clearly could reduce runway incursions. But if they do that, are they opening the runways for more takeoffs and landings?”
Controllers said the option would “definitely help reduce runway incursions,” but added that they are concerned it would lead to traffic jams on the south side, with aircraft requiring instructions from the tower to complete the route.
“It would cut the arrival rate in half,” said Michael D. Foote, president of the Los Angeles tower’s chapter of the National Air Traffic Controllers Assn. “It would be perpetual gridlock.”
Another potential traffic solution that had concerned airport neighbors did not fare well in the NASA simulations. That option swapped runways, with planes landing on the strips nearest the terminals and taking off on those closest to El Segundo and Westchester.
But the option proved “less safe,” said Boris Rabin, simulation manager at FutureFlight Central, because pilots landing on the inside runways found themselves in traffic jams near the terminals, with no place to go.
(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)
LAX Plane Routing
A NASA study found that directing pilots to turn left on a taxiway parallel to the outside runway on the south side of the airfield at LAX would reduce near misses at the airport by eliminating the need for pilots to cross the inside runway.
