New Standard Improves Approaches At Calgary International Airport

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Bill Carey
Nav Canada says a new separation standard it has implemented at Calgary International Airport (YYC), Alberta, allows reduced separations of aircraft making required navigation performance (RNP) approaches to parallel runways, improving traffic flow while reducing noise, emissions and track miles flown to landing.

The result of a three-year project involving multiple parties, the procedure for managing arrivals to parallel runways is seen as a steppingstone to the holy grail of “trajectory-based” operations: time-based management and optimization of flights from takeoff to arrival.

“This is a defined path to the runway, and when you have a defined path to the runway, [you] start to enable that structure around trajectory-based operations,” says Blake Cushnie, Nav Canada national manager for performance-based operations. “It’s a key enabler for the future.

At YYC, aircraft flying RNP Authorization Required (RNP-AR) approaches now can land simultaneously without 1,000 ft. vertical or 3 nm lateral separation, the conventional standard that applies until an aircraft is lined up on the runway, or “established on final.”

The new separation standard, called Established on RNP-AR (EoR), was published in November in the latest update of Procedures for Air Navigation Services Doc. 4444, an International Civil Aviation Organization (ICAO) document. Nav Canada started using it Nov. 8.

The EoR concept stems from a 2011 white paper published by Sheila Conway, a Boeing associate technical fellow. The standard Nav Canada has applied at YYC, and plans for other Canadian airports, is very similar to an EoR procedure developed at Denver International Airport, says Cushnie, who credits FAA technical procedures specialist Ted Goodlin for spearheading that effort. Boeing, ICAO, the National Airlines Council of Canada, Transport Canada, Nav Canada and YYC collaborated to bring it to fruition.

YYC has four runways, including two parallel north-south runways. Of the latter, Runway 17L-35R, which runs 14,000 ft., is Canada’s longest civil runway. It opened in 2014 as part of $620 million runway development program. More than 40% of arrivals at the airport are flown by aircraft equipped to fly RNP-AR, according to Nav Canada.

To take advantage of precise, GPS-guided RNP-AR approaches, pilots must be trained and authorized in advance and their aircraft equipped with navigation performance monitoring and alerting capability.

Properly equipped aircraft are identified with data tags of a slightly different color than other aircraft on controller radar screens. The differentiation enables controllers to organize traffic patterns and ensure that aircraft approved to fly RNP-AR procedures receive the necessary approach clearance. Controllers at YYC track aircraft using conventional Mode C secondary surveillance radar enhanced with alerting tools to flag any deviations, says Cushnie, who notes that RNP-AR-equipped aircraft are inherently accurate.

Managing “high-low” simultaneous approaches to parallel runways using the instrument landing system and maintaining 1,000-ft. vertical separation between aircraft requires a 20-mi. final approach distance to YYC. “What that translates into is a low-level, power-on, high-fuel burn, high-noise scenario on your low-side [aircraft] and a long final for both sides,” says Cushnie. Applying the EoR standard reduces the final approach distance to about 4 mi.

“That is the big initial win for this standard, which is we no longer need to go out that far to establish a separation, because an aircraft on the RNP-AR [approach] is considered established on final as soon as they are on the procedure,” he says. “What that enables is not only a very short final for the RNP-AR aircraft, which in this case is just under 4 mi. in Calgary, but it also means the aircraft on the other side does not have to fly out quite so far as well.”

Applying EoR supports increased use of existing RNP-AR procedures that have been designed at other airports in Canada, and improves traffic flow of both equipped and nonequipped aircraft, Nav Canada says. In December 2017, before implementing the standard, the air navigation service provider (ANSP) recorded 1,100 RNP-AR approaches into YYC. Last December, the first full month since implementation, it counted 2,900 such approaches.

“We basically [more than] doubled our usage by introducing this new ICAO separation standard. Those [approaches] exceeded our personal goals,” says Cushnie. “I am a big believer that this is the new normal for parallel operations.”

Nav Canada estimates that 3,000 RNP-AR approaches per month would save airlines 33,000 track miles to the runway and reduce emissions. Instead of making altitude step-downs on approach, aircraft flying “continuous descent” operations associated with EoR will help reduce greenhouse gas (GHG) emissions by an additional 2,500 metric tons in the first year of implementation, it says.

“These are all lower-level, power-on altitudes that are obviously not fuel- or environmentally efficient, so reducing this extra fuel burn, extra noise, extra GHGs at low altitudes of this volume [of use] is really why we think this is such a fantastic procedure,” says Cushnie.

WestJet and Air Canada, founding members of the National Airlines Council of Canada, are among airlines anticipating benefits from the new standard. WestJet says its Boeing fleet is fully RNP-equipped, as are Bombardier Q400 turboprops flown by sister carrier WestJet Encore.

“After close collaboration with Nav Canada and other partners over several years, WestJet was thrilled and proud to see EoR implemented at Calgary Airport—our home base,” says Chief Technical Pilot David Deere. President and CEO Edward Sims, who previously served as CEO of ANSP Airways New Zealand, says he is “delighted WestJet’s technical teams contributed to this groundbreaking capability.”