In early January, the eighth and final SpaceX Falcon 9 rocket lifted off from Vandenburg AFB in California on a mission for Iridium Communications. Seven of those eight rockets carried 10 Iridium NEXT satellites with the final carrying just five, 66 in all. Each satellite placed itself into a low-earth orbit replacing Iridium’s original satellite-phone constellation launched by Motorola in the 1990s. The new Iridium network will improve satellite phone service, but it will also profoundly improve air traffic control and aviation safety around the world, as each new satellite also carries an ADS-B receiver.
Now if you’re thinking a satellite-born ADS-B receiver is simply redundant to the thousands of ground-based receivers that already exist, you’d be right … almost. Those of us flatlanders who fly IFR in the United States almost never hear ATC utter the phrase “Radar contact lost,” because coverage is just short of awesome around big cities and at least a few thousand feet in the air while en route.
Fly out west though, or up in Alaska, or away from the Atlantic, Pacific or Gulf shores and that phrase is probably more familiar. That’s because the radar technology that bounces a radio signal off an airplane making it visible to air traffic controllers, a system first deployed during World War II, works by line of sight, just like VHF radios. That means aircraft operating in mountainous regions, over open water or jungle can’t always be seen. Aircraft flying near heavy precipitation can also become nearly invisible to ATC on standard radar.
When aircraft fly outside of ground-based radar contact, ATC must significantly increase lateral and horizontal separation standards to keep everyone safe, wasting time and fuel, while also reducing the number of aircraft able to use a given chunk of airspace. There are still plenty of airports around where a departure sits on the ground until an arriving IFR aircraft cancels its flight plan. Without radar information, it’s also nearly impossible for ATC to locate an airplane should they lose radio contact. Think Malaysian flight 370, a Boeing 777 with 239 people on board that went missing in March 2016 and was never found.
The advantage of using Global Positioning System (GPS) based ADS-B is its talent for accurately pinpointing aircraft anywhere on earth at nearly any altitude, provided of course that ADS-B receivers can hear the signal. With space-based receivers augmenting the ones already installed on earth, those ADS-B signals won’t be lost, unless the transponder is disabled for some reason.
While ADS-B receivers on satellites can’t completely prevent another aircraft from going missing, the new system will mean no airplane should ever again go missing with ATC wondering about their last known position. With an ADS-B based ATC system, controllers will see precise position updates as often as once every 15 minutes in the North Atlantic where testing is now in full swing.
In order to make this new-age ATC system viable everywhere, including the U.S., Iridium sells the ADS-B information its satellites receive to a partnership of ATC service providers around the world such as Nav Canada, NATS in the U.K., ENAV (Italy), the Irish Aviation Authority (IAA) and Naviair (Denmark), as well as Iridium, through a new company called Aireon. Working together with Flight Aware, a name already familiar for aircraft tracking data, ATC providers will more easily track an airplane’s callsign, airspeed and altitude, its magnetic heading and transponder code. This positive location information will allow ATC to separate airplanes in areas that were once invisible to them. And the price for entry in this new system doesn’t require extensive aircraft modifications other than what operators are already doing to meet the 2020 mandate.
What It All Means for ATC
Aireon’s supplemental data will appear seamless to air traffic controllers on their radar screens. All controllers will realize is they can now see aircraft data blocks moving across their screens in areas where they never could in the past.
That means when you’re piloting your King Air into Aspen in the not-too-distant future, ATC will be able to follow your flight nearly down to the ground on arrival and see it just seconds after departure. VFR flight following along the West Coast of North America in an ADS-B equipped Bonanza traveling between Seattle and Fairbanks, for example, will be easier and safer.
Flying at 1,000 feet over the dense Amazonian rainforests or across the vast Indian Ocean, ATC will eventually receive position updates as often as once each minute when the service is fully certified.
As already mentioned, Aireon-based ATC is already being tested over the North Atlantic, the busiest oceanic airspace in the world. This allows air traffic controllers to reduce aircraft in-trail separation distances from 40nm to as little as 14nm, making the airspace more flexible, predictable and able to accommodate the immense growth forecasted in the coming years. Aircraft spending less time in the air and able to proceed more directly to destinations saves on fuel and reduces emissions.
No one should underplay the role of satellite-based ADS-B on search and rescue efforts either. Should an airplane like balloonist Steve Fossett’s Decathlon ever again go missing in the Rockies with an ADS-B Out on board, weather permitting, a downed pilot could be located quickly rather than the year it took searchers to eventually locate the adventurer’s taildragger.
Surprisingly, not all countries have yet decided to sign on to receive Aireon’s data stream. During this first phase of testing, many European states as well as Singapore, Malaysia, China, Hong Kong, Taiwan, Japan, South Korea, India and Vietnam have given Aireon the thumbs-up. The FAA plans to begin testing in Miami Oceanic airspace near the end of 2019, with more deployments before 2021. A firm date for fully adding Aireon’s ADS-B data to domestic ATC services will be announced once FAA completes its testing in the Caribbean.
Flying at 1,000 feet over the dense Amazonian rainforests or across the vast Indian Ocean, ATC will eventually receive position updates as often as once each minute when the service is fully certified.
As already mentioned, Aireon-based ATC is already being tested over the North Atlantic, the busiest oceanic airspace in the world. This allows air traffic controllers to reduce aircraft in-trail separation distances from 40nm to as little as 14nm, making the airspace more flexible, predictable and able to accommodate the immense growth forecasted in the coming years. Aircraft spending less time in the air and able to proceed more directly to destinations saves on fuel and reduces emissions.
No one should underplay the role of satellite-based ADS-B on search and rescue efforts either. Should an airplane like balloonist Steve Fossett’s Decathlon ever again go missing in the Rockies with an ADS-B Out on board, weather permitting, a downed pilot could be located quickly rather than the year it took searchers to eventually locate the adventurer’s taildragger.
Surprisingly, not all countries have yet decided to sign on to receive Aireon’s data stream. During this first phase of testing, many European states as well as Singapore, Malaysia, China, Hong Kong, Taiwan, Japan, South Korea, India and Vietnam have given Aireon the thumbs-up. The FAA plans to begin testing in Miami Oceanic airspace near the end of 2019, with more deployments before 2021. A firm date for fully adding Aireon’s ADS-B data to domestic ATC services will be announced once FAA completes its testing in the Caribbean.
Rob Mark is a business aviation pilot, journalist and flight instructor. He also publishes the award-winning industry blog, Jetwhine.com.
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