[Avionics Today 11-24-2014] The FAA
announced its latest Metroplex-related airspace improvement activity under its nationwide rollout of the NextGen program: a new Optimized Profile Descent (OPD) for the Washington, D.C. Metroplex initiative. According to a statement from the agency, the Washington, D.C. airport system is the first Metroplex in the United States to now have three "satellite-based highways in the sky running side by side by side, each dedicated to one of the three major airports in the region."
An aircraft takes off from Reagan National Airport. Photo: Metropolitan Washington Airports Authority.
OPD is the FAA
's description of a method of operating an aircraft on its approach to an airport by minimizing changes in engine thrust through the use of a favorable initial flight path angle and by strategic flap/landing gear management. Instead of the traditional method of landing an airplane, which follows a stair-step approach, constantly lowering the altitude through reduced engine thrust, OPDs allow the pilot to follow a more efficient descent trajectory with less time spent in level flight, resulting in reduced fuel burn and carbon emissions.
"The easiest way to understand how they work is they enable aircraft to make a smooth, continuous descent from cruising altitude to the runway," Paul Takemoto, a spokesperson for the FAA told Avionics Magazine. "Traditional descents (using ground-based navigation aids instead of satellite-based) step down to lower altitudes; each step-down burns fuel and also requires a voice clearance with a controller. OPDs are like sliding down the bannister, with only voice comm at the beginning and end. They save time, fuel and reduce carbon emissions while also eliminating the possibility of voice comm errors."
According to the FAA, about 97 percent of commercial aircraft serving the D.C. Metroplex airports are equipped to use OPDs. Included in the D.C. Metroplex airport system are Baltimore/Washington International Thurgood Marshall Airport (BWI), Dulles International Airport (IDA) and Ronald Reagan Washington National Airport (DCA). The OPD into Baltimore/Washington opened this month, joining existing OPDs at Dulles and National, all three of which are among the busiest airports in the National Airspace System (NAS).
This most recent announcement of the improvement to the Washington, D.C. Metroplex follows an announcement made by the agency last week regarding the completion of the North Texas Metroplex
, implementing similar airspace efficiency improvements for flights serving Dallas/Fort Worth (DFW) International Airport and Dallas Love Field (DAL). The North Texas announcement also followed the completion of the Houston Metroplex project
for flights serving David Wayne Hooks Memorial (DWH), William P. Hobby (HOU), George Bush Intercontinental (IAH) and Sugar Land Regional (SGR) airports.
Due to special use and military airspace within the Washington, D.C. Metroplex airport system, the airspace has become increasingly congested as air traffic volume in the region and throughout the NAS continues to increase. For example, passenger traffic at Reagan National Airport exceeded 20 million in 2013, well in excess of the 15 to 16 million passengers the airport has traditionally served and the fourth consecutive year of record passenger levels, according to the Metropolitan Washington Airports Authority. Thus, the FAA’s OPD rollout in this area is much needed.
"Historically the way we've handled aircraft in our air traffic system has been more of a structure of a step-down approach, and now, with these more environmentally friendly satellite-based procedures, we're essentially sliding down a stairwell. Simply put, what we are trying to do with the procedures are provide more environmentally friendly procedures or ways arriving and departing airports with the least amount of impact on the environment," Brian Townsend, a captain and tech pilot for the airspace optimization division of American Airlines said in a video describing the new OPDs in the D.C. Metroplex.
The FAA achieved the deployment of the new OPDs by organizing teams of aviation professionals, including Air Traffic Controllers (ATCs), pilots, avionics manufacturers and more. The teams analyze the current flow of aircraft and then create more efficient paths into the busy airspace. According to the FAA, the three new flight paths in the D.C. Metroplex include the Anthem OPD into BWI, the Gibbs OPD into Dulles and the Freedom OPD into Reagan National. All three use the precision and predictability of satellite-based navigation to allow aircraft to follow the most fuel-efficient landing approaches into the different airports.
Under the deployment of the three OPDs, the FAA estimates airlines will see a reduction of the amount of fuel they burn by 2.5 million gallons and will also reduce carbon dioxide emissions by 25,000 metric tons. Implementation of the third OPD in the D.C. Metroplex was achieved ahead of the start of the holiday travel season, when the agency expects the number of flights on Tuesday and Wednesday to be about 1.5 percent over a typical Tuesday and Wednesday. Saturday and Sunday will see a 15 to 18 percent increase in flights over a typical Saturday and Sunday. During this period, the Department of Defense is also releasing unused military airspace to the FAA from Wednesday, Nov. 26 through Sunday, Nov. 30.
In addition to improving air traffic flows at Baltimore Washington International, Dulles and Reagan, the FAA said the three OPDs will help improve the efficiency of flights at nine smaller airports in the region, including: Easton/Newman, Frederick Municipal, Leesburg Executive, Montgomery County Airpark, Manassas Regional, Eastern West Virginia Regional, Winchester Regional, Stafford Regional and Martin State, according to an emailed statement.
"The OPDs will help flights to all area airports because they greatly reduce congestion in the area. Air routes over Metroplex regions prior to the implementation of these procedures are like a complicated, though safe, web. OPDs serve to eliminate much of the entanglements, making things easier for everyone," said Takemoto.