DFW’s Perimeter Taxiway

DFW International Airport is in the midst of installing a new perimeter taxiway that will have a dramatic impact on reducing runway incursions, and has become a leader on the logistics of the issue.

Construction ‘Nearly Unnoticeable’
Crites comments that the construction of the perimeter taxiway system, which began in October 2006, is “nearly unnoticeable on the active airport operations area.”

The perimeter taxiway is divided into four quadrants and will come online in phases, with the first phase — around the southeastern quadrant of the 18,000-acre property — expected to be complete by fall of 2008. “We want to put in the first quadrant to verify that all of our best thinking on the part of the pilots, controllers, FAA, airport, and the airlines is going to be realized,” says Crites.

Once the first quadrant is operational, the airport expects to get feedback from operators on the field before proceeding with the final three phases.
The cost of the first quadrant is estimated at $66 million, which includes the cost of relocating a roadway, Crites says. The taxiway itself is roughly $42 million for each quadrant. “So for about $168 million, I’ve just increased the safety of this airport, eliminated runway crossings, and boosted the efficiency of the airport by 35-plus percent — you can’t buy that with a new runway. You can’t buy that with probably two new runways.”

The system will extend an additional 2,650 feet from the end of the runway and Crites says that even though it means an additional two minutes, on average, in taxiing time, it is a very deliberate number. “The reason why it’s 2,650 is we’re looking at not only allowing aircraft to taxi under a departing aircraft, but we want to be able to taxi underneath arriving aircraft to the inboard runway,” Crites says.

“By allowing aircraft to taxi on a perimeter taxiway, underneath an arrival stream, this allows them to have unrestricted feed to both runways for departure scenarios, and to do so safely.

“Once again I’m eliminating more runway crossings, reducing communications, eliminating the runway incursion potential, and maximizing the efficiency of the airport to its original design levels because we don’t have any of these interactions going on.”

The distance the perimeter taxiways are from the runways is such that they will be clear of the TERPS (Terminal Instrument Procedures) surfaces — imaginery surfaces that should not be penetrated to provide the maximum enevelope of safety for operating aircraft, explains Crites.

And even though taxiing time will be increased by some two minutes, aircraft should experience an overall improvement in time operating at the airport.
Comments Crites, “Where you make up for this is you’re not waiting to cross a runway and you’re moving more aircraft during peak periods — your out-to-off times decrease 4.28 minutes. So, at the end of the day, I’m reducing your overall time operating by 2.28 minutes.”

Safety, of course, was the original goal intended with the perimeter taxiway, but the bonus benefit is it “restored, at high traffic levels, the optimal capacity of the runways because you deconflicted the operations,” says Crites. “They don’t overlap; they’re independent of one another instead of dependent on one another... Another way to frame that is, no matter what the traffic level intensities, the airport can always operate at the original traffic capacity design levels that the FAA and the airport had in mind for those runways.”

Other good news for the project, says Crites, is that it does not adversely impact the communities surrounding the airport. Because aircraft will spend less time operating at DFW, emissions will be lower and, at the same time, airlines will save money on fuel. “It’s a win-win-win across the board from safety to efficiency, to community relations, to environmental,” he says.

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