Imagine planes arriving at Denver International Airport relying on GPS satellite data to navigate smoothly and seamlessly from an altitude of 23,000 feet to runway touchdown in a way that reduces aircraft noise, fuel burn and emissions.
Officials from the Federal Aviation Administration, the air-traffic controllers union, DIA and leading airlines in Denver have been working for months on a comprehensive new satellite-based navigation system that experts say should improve safety and reduce flight times.
The system, called Area Navigation (RNAV) and Required Navigation Performance (RNP), is designed to have arriving aircraft use a technique called optimized profile descent for a smooth, continuous approach to the runway instead of the stepped-down technique required by current air-traffic control procedures.
Planes approaching DIA now typically are directed by controllers to proceed from one navigational fix to another in a linear fashion that can add time to a flight.
Controllers also direct pilots of arriving aircraft to reduce altitude and level off, then repeat such stair- stepped maneuvers until they reach the runway.
It’s an inefficient technique that can be overcome with the new satellite- based navigation procedures, said Mark Phipps, the FAA manager who is heading up the RNAV/RNP project at DIA.
“Every time you level off, you push the throttle back up and burn more fuel,” said Phipps, who is support manager for airspace and procedures at the FAA’s terminal radar control facility near DIA, known as Denver TRACON.
Advanced satellite technology should give aircraft the ability to navigate more precisely in ways that could yield as much as a 6 percent reduction in fuel burn and emissions at DIA, Phipps said. “It’s enormous.”
Once the procedures are in place, pilots of properly outfitted planes arriving at DIA should be able to bring the throttles back to idle until final approach for a continuous arrival that could save as much as 400 to 800 pounds of fuel per flight, said Capt. Joseph Burns, managing director for technology and flight test at United Airlines.
A gallon of fuel weighs about 6 pounds.
United has teamed with the FAA on the RNAV/RNP project, and officials have used simulators at United’s flight training center in Stapleton to help design the new navigation procedures.
United, DIA’s largest carrier, hopes the procedures will allow it to to “shave off” between 5 and 20 miles from each Denver flight, Burns said.
FAA expects to have the new arrival and departure routes designed soon, but it will take more than a year to conduct an environmental review of the procedures.
Once they are in place at DIA, the procedures could lead to a 35 percent to 40 percent reduction in the number of required radio transmissions between controllers and pilots, according to Phipps and Dave Riley, a TRACON controller who heads the facility’s unit of the National Air Traffic Controllers Association.
Reducing controller-pilot communications should increase safety, Riley said.
“One of the biggest reasons for errors is human,” he said, referring to “hear-back/read-back errors” that can lead to aircraft getting too close to each other.
Other airports around the country, including Dallas-Fort Worth International, Atlanta’s Hartsfield-Jackson International and Seattle-Tacoma International, already are using elements of the satellite-based navigation system.
At DFW in Dallas, pilots have been using RNAV on what are called standard instrument departures, or SIDS.
The aim, as with satellite-guided arrivals, is more precise and efficient flying.
Yet earlier this year, American Airlines issued a bulletin to its pilots, saying: “In January and February 2010, we experienced a significant increase in the number of deviations on the DFW RNAV SIDS.”
Deviations potentially put planes too close to other aircraft, and in some cases occurred because pilots had the wrong runway entered in the flight management system computer before takeoff, the bulletin said.
Jeffrey Leib: 303-954-1645 or jleib@denverpost.com
