FAA Touts Advantages Of OPD At Denver International Airport

Seven miles above the Mile-High City, the pilot of Kim Day's flight pulled the engines to idle and began a 150 nautical-mile glide to earth. The pilot was flying an Optimized Profile Descent (OPD) into Denver International Airport, rather than the traditional stair-step descent.

OPDs provide a smoother ride while using less fuel, a benefit for both passenger and airlines. But for Day, manager of Denver International Airport, this was the culmination of a three-year process to create one of the most comprehensive operational networks of NextGen satellite-based arrivals and departures in the nation. The FAA estimates these procedures will annually save operators $9.8 million from using 3.2 million gallons less fuel.

Day and other Denver-area airports and aircraft operators worked with the FAA to design a suite of performance-based navigation procedures that make the best use of the airspace around the Denver metroplex, enabling more flexibility and better access to the airports in the area. A metroplex is a geographic area with several airports and lots of air traffic that interact in the same airspace. The FAA is working to improve how air traffic flies into, out of and through metroplexes rather than dealing with airports one at a time.

"It was clear to me that the things we had implemented were having the effect that we planned," said Day. She said she is impressed with the initiative the FAA took to get all of the local stakeholders involved in the project. Approximately 80 percent of the aircraft that fly in and out of Denver International are equipped to fly the new procedures.

The Denver metroplex now has a network of 51 satellite-based procedures designed to provide more direct routes, deconflict the airspace, save fuel and reduce emissions. This includes 21 arrivals with OPDs, 16 departures and two GPS approaches, which were published in January 2013. The procedures are enhancing safety with more stabilized approaches that reduce the number of go-arounds, among other benefits.

"We have seen about a 35 percent decrease in the number of go-arounds caused by aircraft coming in too high or too fast," said John Connolly, acting FAA air traffic manager at Denver Tower. "This is because aircraft on the new arrival procedures are more stabilized on their final approach as they usually arrive on a more predicable course and speed."

Twelve sophisticated approach procedures, known as Required Navigation Performance Authorization Required (RNP AR), went into operations in late June 2013. These RNP AR procedures provide a more stable but curved approach, equaling a shorter flying distance. Flying these approaches requires specific aircraft instruments that contain the aircraft in a very narrow and precise corridor of airspace.

In addition to Denver International, which is the fifth busiest airport in the country for passenger traffic, the Denver metroplex also includes Centennial Airport. Centennial is one of the top 10 most active airports for domestic business jet operations in the United States. The 6,000 businesses located within a few miles of Centennial represent more than a quarter of Colorado's gross domestic product, said Robert Olislagers, Centennial's executive director.

Corporate pilots at Centennial benefit from flying more stable descents that keep them at higher altitudes longer. In many cases, this reduces exposure to mountain wave turbulence. Olislagers, who was part of the planning process, said the new routes for Centennial are safer and more direct, enabling pilots to fly fewer miles and conserve fuel.

Buckley Air Force Base, the United States Air Force Academy Airfield and four additional general aviation airports — Rocky Mountain Metropolitan, Fort Collins-Loveland, Front Range and Greeley-Weld County — round out the Denver metroplex. Leaders of these facilities collaborated in the planning and design of the new procedures.

The effort also added a new arrival procedure to Colorado Springs Airport even though it is outside the Denver metroplex. This procedure provides a more efficient route into Colorado Spring and keeps the traffic away from Denver arrivals.

Day is not the only one who is excited about the new procedures. "The pilots are thrilled, the operations people at the airlines are thrilled," she said.

United Airlines was the lead carrier working with the FAA on the Denver project. "This has been the best collaborative effort I have ever seen on this type of project," said Mark Sims, a United Airlines technical pilot who led the Denver effort for his airline.

All of United's aircraft are equipped to fly satellite-based procedures and the airline estimates saving 100-200 pounds of fuel on each arrival. With an average of 120 flights per day, that equates to an estimated annual reduction of 4.35 — 8.7 million pounds of fuel and 13.8 — 27.6 million pounds of carbon dioxide emissions. That figure could triple when an arrival procedure connects to an RNP procedure and eliminates about ten miles of flying for aircraft equipped to fly the more sophisticated routes.

FMI: www.faa.gov