Thoughts in Cruise

Cruising across the wilds of central Nevada the other day, my thoughts turned to GPS and the frequent outage NOTAMs we get when the military decides to play games with the signals. Its not uncommon for wide swaths of the western deserts to have warnings that GPS might be unreliable for significant portions of time. Now don't get me wrong - I am the very understanding of the potential military issues of having or not having GPS available (by the military and everybody else), as well as the need to train for use without it. We have to remember that initially, GPS was designed as a military asset - the fact that it has now been incorporated as key technology in everything more advanced than a toaster is simply a testament to its universal acceptance.

I am also a fan of the concept of NextGen - the ultimate air traffic control system that is the end goal of all this ADS-B work we're doing. Basically everything in the air puts out its position so everyone else knows it is there, and you do away with all of the ground radars. Elegant, fast, works without a wide distribution of ground equipment of different vintages and pedigrees. But getting there is tricky, That is a whole lot of change that has to occur.

And one of those changes is that if everyone from us lowly GA pilots up through the airlines and military is dependent on GPS to keep traffic separated, then you absolutely, positively can not let that signal go away - not with tens of thousands of unsuspecting commercial passengers unknowingly depending on it to prevent a reoccurrence of the bad old days of the early 1950s, when several airliners collided before the age of modern air traffic control.

What really has me thinking about this is that nowhere am I seeing a hue and cry from people who recognize this as a problem. I have yet to read a single article that says that the military has promised not to do this spoofing starting in 2020. But if they really did pull out all the radars (won't happen), and the airliners all equip (they aren't going to be anywhere near close to being equipped by 2020), then the only way to separate traffic with all those blissfully ignorant general public travelers on board will be by GPS.  Why aren't we all talking about this?! It would scare the crap out of the average passenger (who worries about fan disks coming apart) if they knew about it.

I am not really into conspiracy theories, but don't you think the airlines will be happy when half the GA fleet is grounded, and they haven't had to spend any money on equipping because they have a deferral? Is there any real intent to make GPS the sole source of traffic separation in anything like the early 2020s?

Now I'll be honest, I really like having traffic and weather in the cockpit. I have gotten weather through satellite for years, but it is nice to have it free.  But the ATC part of the system is just flat broken unless EVERYONE is playing, including the military - and they don't appear to be. I'd love to have NextGen completely up and running - but there are key blocks that aren't being put in place to keep it from falling down.

Fortunately, the other day, no one was playing games, and the IFR navigator that feeds my ADS-B, along with the three VFR GPS receivers in my EFIS, the GPS in my iPad, and the extra receiver in my iPhone all kept tracking and telling me that yes indeed, I really did have a headwind that was going to make me late and put me in the height of the afternoon bumps across the mountains. But that's another story.


Paul Dye

Paul Dye, Kitplanes® Editor in Chief, retired as a Lead Flight Director for NASA’s Human Space Flight program, with 40 years of aerospace experience on everything from Cubs to the space shuttle. An avid homebuilder, he began flying and working on airplanes as a teen, and has experience with a wide range of construction techniques and materials. He flies an RV-8 and a Subsonex jet that he built, an RV-3 that he built with his pilot wife, as well as a Dream Tundra they completed. Currently, they are building a Xenos motorglider. A commercially licensed pilot, he has logged over 5000 hours in many different types of aircraft and is an A&P, EAA Tech Counselor, and Flight Advisor, as well as a member of the Homebuilder’s Council. He consults and collaborates in aerospace operations and flight-testing projects across the country.

7 Replies to “Thoughts in Cruise”

  1. So if the airlines are not going to be fully equipped with ADS-B by Jan. 1, 2020 while GA will be, then how does it make sense to turn over ATC to the airlines?

    When the argument for privatizing ATC is made that the FAA is advancing Next Gen. too slowly, perhaps our GA representatives should point out that it is actually the airlines who are now delaying full adoption rather than the FAA.

  2. I am a firm believer that if the FAA were regulating automobiles,
    half the population would still be driving horse and buggies !

  3. The additional problem with ADS-B is that it is only mandated where a transponder is required now and only Out is required, not In. Here, in AK where I am for the summer, my ADS-B is almost worthless, as some airplanes, including 135 operators, don’t even have transponders installed. Others seem to turn their transponders off to keep competitors from knowing their whereabouts via flight tracking software. I find that ironic in an area where the proof of concept was proven via the Capstone program.

    So after January 1, 2020 the reality is that not much will have changed. We aren’t going to be seeing all the traffic on our fancy gizmos unless we dedicate our flying to Class A, B, C airspace or above 10,000’ (more than 2,500’ AGL), and not everyone will have In. Swell...

    I love having ADS-B In and Out, but the implementation by the govt is fraught with foolishness.

  4. I use an iPad with ForeFlight instead of a certified GPS navigator, and I've never noticed ANY impact from those scheduled GPS outages. I wonder if it's because the iPad's navigation chipset also includes GLONASS capability, and when the GPS outages take place, GLONASS is still up (and perhaps vice-versa)?

  5. Given the current fiscal constraints imposed by our government, what makes you think that Military aircraft were ever going to be equipped with ADS-B. I can tell you that if you brought the ADS-B conversion up with military pilots they'd just tell you "ADS-what?" Military aircraft will be operating Mode III-C transponder-only for the indefinite future.

  6. Hi Paul,
    I fly a RV-10 with a fully equipped and fly IFR on trips using the low altitude enroute routes. I would suggest especially on the West Coast to use these routes and flight following for the VFR pilots. Yes, I have ADS-B. I used to live in San Diego for many years and never had a problem with the routes and flight following.

  7. Your article is great, Paul. I too like ADS-B weather in the cockpit. "Prepaid by other means" is not the same as "free." About 18.000 midair collisions in US airspace annually that won't be prevented by looking at the ADS-B "in" display in the cockpit (bird strikes). GPS MIJI and spoofing equipment is fairly cheap, easy to build, easy to deploy, has been available for years, and could cause immense disruption to the ATC system. It could be a fantastic terrorist tool to cripple the airlines with little fear of being caught much less having to be a martyr. Your reservations and questions are interesting, the answers (if given) could be even more so!

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