Aviation safety is top-of-mind for everyone in the industry, from manufacturers to airlines, airport authorities, air traffic controllers and the Federal Aviation Administration (FAA). The air traffic control system for managing terminal area airspace for both the FAA and Department of Defense (DoD), the Standard Terminal Automation Replacement System (STARS), has been helping keep aviation safe since 2000. A potential new STARS capability, called Approach Runway Verification (ARV), is being evaluated to ease airport safety concerns by warning controllers if an aircraft is lined up to land on a taxiway or on the wrong runway, taking aviation and airport safety to the next level.
STARS, developed and provided by Raytheon, receives radar data and flight plan information and presents the information to air traffic controllers in both control towers and terminal radar approach control (TRACON) facilities so they can monitor, control, and accept hand-off of air traffic. Through Terminal Controller Workstations (TCW) and Tower Display Monitors (TDW), controllers can see six distinct levels of weather data simultaneously with air traffic, allowing them to direct aircraft around dangerous weather. STARS is used in airports and TRACONs across the United States to enhance safety on the ground and in the air.
With the proof of concept of the STARS ARV, the company has developed a capability that could provide another layer of safety and control for controllers, airports, pilots and passengers. The genesis of ARV was a July 2017 event at San Francisco International Airport (SFO), when arriving Air Canada Flight 759 came within approximately 50 feet of landing on a taxiway that was occupied by several fully loaded aircraft waiting to depart. This incident – while very rare – was not the first time something like this had happened. In fact, at Boston Logan airport in 2016, weather conditions had forced the reconfiguration of landing and takeoff procedures for the airport. Vigilant controllers there averted a similar landing on taxiway incident by ordering the pilot to go-around.
“If an arriving aircraft aligns with a taxiway, where multiple aircraft may be awaiting takeoff, obviously the consequences could be dire,” said Simon Hennin, Raytheon STARS Technical Director. Hennin recently gave a presentation at the Air Traffic Control Association’s Technical Symposium in Atlantic City about STARS ARV. Symposium attendees voted his presentation and paper “Best Technical Paper.”
In the case of the Air Canada flight at SFO, the flight had been cleared for a visual approach, and so was not being guided by the instrument landing system. After the incident was reported, the STARS team accessed recordings from the SFO STARS system, reviewed the track of the Air Canada flight and “created a prototype to see if we could raise an alert to a controller if an arriving flight lined up on a taxiway,” according to Hennin.
The prototype successfully generated the alert, and – of equal importance – did not create an alert for aircraft that were lined up correctly for landing.
“Alignment of a flight with a taxiway is thankfully quite rare; alignment with the wrong runway appears to be a more regular occurrence, but still low frequency relative to the thousands of error-free approaches and landings that occur every single day,” Hennin explained. “In some sense, we are trying to detect a needle in a haystack – and we’re trying to do it without false alarms. While we could wait a long time before knowing whether the tool detects the next taxiway event, it will become evident very quickly if the tool has an unacceptable false alarm rate. A controller’s response to an alarm from this tool would have to be immediate and automatic – to order the pilot to perform a go-around. As you can imagine, controllers and pilots alike will not appreciate having to do this for the wrong reason.”
The STARS ARV proof-of-concept prototype was first demonstrated in the fall of 2017, and the team now is evaluating how to convert that into a real, operational capability that could be put into the field as part of the STARS system.
Jack McAuley, Raytheon’s Program Director for Air Traffic Systems Automation, said that the main benefit STARS ARV can bring to the FAA and the entire aviation community is enhanced safety. He pointed out that it also can be used as an added layer of safety when weather causes an airport to change landing and takeoff configurations.
“In unusual weather conditions that force the airport into an uncommon configuration, controllers are faced with pilots who may not be familiar with the airport operating in that configuration,” McAuley explained. “This could lead to an incident similar to the one at Boston Logan. The STARS ARV capability could be used in these situations to help avoid potentially tragic incidents.
“It is an automated enhancement designed to enhance airport safety that could benefit the FAA and the entire aviation community,” McAuley continued. “The STARS team saw the SFO incident and knew about the Boston Logan incident and wanted to find a way to keep something like it from happening again. ARV could do that for aviation and could be integrated into the baseline STARS configuration and tailored to specific airports across the National Airspace System (NAS).”
Aviation safety cannot be taken for granted, and everyone involved – from manufacturers to airlines, airport authorities, air traffic controllers and the FAA – must continue to strive for improvements every day. STARS ARV may help eliminate one potential hazard at American airports in the future.