- In October 2013, United Airlines began an In-Trail Procedures (ITP) trial with the FAA in select airspace over the Pacific Ocean using 12 Boeing 747-400s equipped with Automatic Dependent Surveillance-Broadcast (ADS-B) In and ITP software. American Airlines and Delta Air Lines participated in a similar ITP trial over the North Atlantic.
- Transatlantic ADS-B ITP-equipped flights saved an average of 670 pounds of fuel and equipped transpacific flights saved 521 pounds.
- Separation Management
- Provides controllers with tools to manage aircraft in a mixed environment of varying navigation equipment and wake performance capabilities.
One key advantage of Automatic Dependent Surveillance–Broadcast (ADS-B) is enabling pilots of transoceanic flights to climb or descend to more optimal, fuel-saving altitudes. In-Trail Procedures (ITP), an ADS-B In application, enables reduced separation between aircraft.
Since radar is not available over most oceanic airspace, pilots have had to maintain aircraft separation of about 80–100 nautical miles — often limiting their ability to change altitude. With satellite-enabled navigation procedures that use GPS and other navigation sensors, this separation can be reduced to about 30 nautical miles.
In October 2013, United Airlines began an ITP trial with the FAA in select airspace over the Pacific Ocean using 12 Boeing 747-400s equipped with ADS-B In and ITP software. American Airlines and Delta Air Lines participated in a similar ITP trial over the North Atlantic.
In an FAA report summarizing the benefits of ADS-B and ITP dated December 2015, transatlantic ADS-B ITP-equipped flights saved an average of 670 pounds of fuel and equipped transpacific flights saved 521 pounds. For ITP-equipped aircraft, operators saved an average of 573 pounds of fuel per flight compared to aircraft without ITP equipment.
Traffic levels are greater over the North Atlantic region than the Pacific, and that traffic is more tightly spaced. This accounts for the disparity in fuel savings, and can make it more difficult for transatlantic flights to receive air traffic control (ATC) approval for climbs.
In addition to potential fuel savings, ITP also enhances pilots’ situational awareness. Aircraft equipped with ITP have an ADS-B In display that gives pilots a top-down view of the surrounding airspace and a vertical view that shows the altitude of nearby aircraft. With a better understanding of the complete traffic picture, flight crews can make more-informed requests of ATC— with a better chance of getting approval for their occasional ITP climb requests.
"What that situational awareness allows our crews to do is to make more intelligent decisions about when they make a normal climb — not an ITP climb — and whether it will be approved or not," said Rocky Stone, chief technical pilot for surveillance systems at United Airlines.
"Because of that, they’re making smarter requests for climbs," he added. "The new display shows all ADS-B traffic within a 250-mile radius, compared to 40 miles with the older system. There’s much more information for the pilots to base their decision on."
In discussions between United pilots and human factors experts at the John A. Volpe National Transportation Systems Center in Massachusetts, pilots generally rated the value of ITP as high, not for the procedure itself, but for the situational awareness enabled by the ITP display. Many pilots said that they could make more efficient and effective altitude change requests based on the ITP traffic display, and that there could be an economic benefit for using the display to make a request.
The FAA will implement ITP software changes to Advanced Technologies and Oceanic Procedures (ATOP) at the Oakland Air Route Traffic Control Center this year, with the New York and Anchorage centers to follow. After the software updates, any ITP-equipped aircraft operating in this airspace may request an ITP maneuver.
"A few years ago, industry prioritized a number of ADS-B In applications and asked the FAA to demonstrate benefits for them," said David Gray, surveillance and broadcast services program manager for the FAA. "This ITP report not only shows that NextGen is here today and that the benefits are real, but it also highlights the importance of FAA’s continuing work on ADS-B In applications."