Tag: GPS

It’s About Time!

I just added ADS-B Out to my airplane. I’ve been looking forward to this moment for a very long time—48 years to be exact.

Air Facts (May 1970)

Air Facts (May 1970)
click image to read article

It was 48 years ago that my very first aviation article was published. Its title was “The Role of Computers in Air Traffic Control.” I was 26 years old at the time, not long out of college, and starting a career in computer software at the dawn of the computer age. I’d only been a pilot for five years and an aircraft owner for two.

I timidly submitted the 3,000-word manuscript to Leighton Collins (1903-1995), the dean of general aviation journalists (and Richard Collins’ dad). Leighton founded his magazine Air Facts in 1938, the first GA magazine to focus primarily on safety. In the ‘50s and ‘60s, Leighton became a pioneer in using GA airplanes to fly IFR, something that was considered risky business at the time. In 1970, I was a newly-minted CFII and Skylane owner, and Leighton was my hero and Air Facts my bible.

Leighton loved my article, and published it in the May 1970 issue of Air Facts.  I was thrilled. I was also hooked and went on to write more than 500 published aviation articles between then and now.

How big is the sky?

I’d been instrument-rated for about four years when I wrote that article, and had thought quite a bit about the differences between VFR and IFR flying:

A pilot flying VFR in clear weather is unlikely to see more than a few other aircraft on a typical flight; to him the sky seems to be a rather empty place. Yet to the pilot stuck in an IFR hold with an estimated-further-clearance time forty-five minutes away, the sky seems to be an order of magnitude more crowded. Why? Clearly there is no shortage of airspace; every VFR pilot knows that. The aircraft flying under IFR have the best equipment and the most proficient pilots aboard. Where does the congestion come from?

My conclusion was that the fundamental difference between VFR and IFR lies in who is separating aircraft. VFR pilots are responsible for their own separation, while IFR pilots rely on air traffic controllers to keep them separated from other traffic. Thus, I reasoned, the comparatively low capacity of the IFR system must be attributable to some failing on the part of controllers. Yet as someone who has spent many hours visiting ATC facilities and observing controllers at work while plugged in beside them, I can testify that these folks are amazingly sharp, skilled, and well-trained professionals who do their jobs exceptionally well.

So why can’t these hotshot controllers separate IFR aircraft nearly as efficiently as VFR pilots are able to separate themselves? My conclusion was that the very nature of the separation task is fundamentally different:

A pilot is concerned solely with the one aircraft that he’s flying, but a controller must keep track of several aircraft at once. Give a person several things to do at once—even simple things like head-patting and tummy-rubbing—and his performance in each task drops sharply. Keeping track of a high-speed airplane is considerably harder than either head-patting or tummy rubbing. Keeping track of a dozen such airplanes travelling in random directions at random altitudes is simply beyond the capabilities of any human.

Our IFR system is designed to simplify the controller’s job to the point that it is within the realm of human capability. It does this primarily by eliminating the amount of randomness the controller must deal with. It strings airplanes along a few well-defined airways/SIDs/STARs, confines them to a few standard altitudes, and sometimes slows them down to a few standard speeds. Doing these things makes the airplanes much easier for the controller to keep track of and keep separated, but it also wastes most of the available airspace and reduces the capacity of the system.

Do we really need ATC?

It seemed to me that the capacity of the IFR system could be vastly increased if we could just stop relying on controllers to separate airplanes and enable pilots to self-separate, much as they do when flying VFR. In 1970 when I wrote the article, we were right on the cusp of two major technological breakthroughs that I believed had the potential to make that possible.

GPS ConstellationOne of them was the promise of accurate satellite navigation. The Naval Research Laboratory had launched its Timation satellites in 1967 and 1969, the first ones to contain accurate atomic clocks suitable for navigation. Meantime, the Air Force’s Space and Missile System Organization was testing its more advanced system (codenamed Project 621B) for aircraft positioning between 1968 and 1971. These were the progenitors of today’s GPS system—something I could see coming in 1970, although a seriously underestimated how long it would take to become operational. The first constellation of 10 “Block-I” GPS satellites wasn’t in orbit until 1985, and the system’s full operational capability wasn’t announced until 1995.

MicroprocessorThe second breakthrough was large-scale integration (LSI)—the creation of integrated circuits containing tens of thousands of transistors on a single silicon chip—and the emergence of the microprocessor. Microprocessors weren’t yet invented in 1970 when I wrote the article, but as a computer scientist (my day job at the time) I could see them coming, too. As it turned out, Intel introduced its 4004 microprocessor in 1971, its 8008 in 1972, and the 8080 (which really put microprocessors on the map) in 1974. This watershed development made it feasible to equip even small GA airplanes with serious computing power.

The ATC system of tomorrow

Traffic DisplayIn my 1970 Air Facts article, I painted a picture of the kind of ATC system these new technologies—GPS and microcomputers—would make possible. I postulated a system in which all IFR aircraft and most VFR aircraft were equipped with a miniaturized GPS receiver that continually calculated the aircraft’s precise position and a transmitter that broadcast the aircraft’s coordinates once per second. A network of ground stations would receive these digital position reports, pass them to ATC, and rebroadcast them to all aircraft in the vicinity. A microcomputer aboard each aircraft would receive these digital position reports, compare their coordinates with the position of the host aircraft, evaluate which aircraft are potential threats, and display the position, altitude and track of those threat aircraft on a cockpit display.

Such a cockpit display would enable IFR pilots separate themselves from other aircraft, much as VFR pilots have always done. It would permit them to fly whatever random routes, altitudes and speeds they choose, giving them access to the same “big sky” that VFR pilots have always enjoyed.

I theorized that pilots are highly incentivized to self-separate and would do a much better job of it than what ground-based air traffic controllers can do. (Just imagine what driving your car would be like if you weren’t allowed to self-separate from other vehicles, and instead had to obtain clearances and follow instructions from some centralized traffic manager.)

What took so long?

NextGen controllerWhen I re-read that 1970 article today, it’s truly eerie just how closely the “ATC system of the future” I postulated then resembles the FAA’s “Next Generation Air Transportation System” (NextGen) that the FAA started working on in 2007 and plans to have fully operational in 2025. Key elements of NextGen include GPS navigation and ADS-B—almost precisely as I envisioned them in 1970.

I was wildly overoptimistic in my prediction that such a system could be developed in as little as five years. If the FAA does succeed in getting NextGen fully operational by 2025, it will be the 55th anniversary of my Air Facts article.

NextGen also includes improved pilot/controller communication (both textual and VOIP) and various improvements designed to allow use of more airspace and random routes. Sadly, it stops well short of transferring responsibility for separating IFR aircraft from ATC to pilots as I proposed in 1970—although our aircraft will have the necessary equipment to do that if the FAA would just let us. Maybe that’ll have to wait another five decades until NextNextGen is deployed (and there’s an autonomous self-piloting octocopter in every garage).

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

The return of the “Since You Asked” poll

FT dig tagYou may have noticed that our much-loved columnist Rod Machado changed neighborhoods in the magazine.

Starting with the September 2015 issue, Rod discontinued his “Instructor Report” and resumed his popular “Since You Asked” column. It now resides each month in the Preflight section.

When Rod was contributing “Since You Asked” in previous years, we took advantage of new-ish technology to include a reader poll in the digital edition whenever possible. (For paper subscribers, the “Plus” icon [show above] means there’s a digital component to any given article.)

With the return of “Since You Asked,” we also are returning to digital polls. In October, we asked readers whether they used a GPS during dual cross-country flight training.

The vast majority (57 percent) of respondents said they did not use a GPS. Another 29 percent said they didn’t use one because the airplane didn’t have one. And 14 percent said they did use a GPS during dual cross-country flight training.

The poll question concerned a reader’s question to Rod: “Should student pilots be allowed to use a GPS’s moving map display during their dual cross-country flights?”

Rod said he has no problem with student pilots using a GPS moving map at any time during their cross-country training, so long as they meet a few requirements: “Technology should never be used as a substitute for the acquisition of the basic skills replaced by that technology. As long a a student learns the basic navigation skills required by the regulations first, then the use of a GPS moving map seems reasonable.”

Rod clarified his comment by adding that it’s not reasonable to expect a student to learn dead reckoning and pilotage skills while simultaneously monitoring a moving map. His responses, as always, are thoughtful and make the basis of a good discussion for you and your flight instructor. Preview the October 2015 digital issue here. (You don’t need to log in; simply push the “Preview” button on the login screen.)—Jill W. Tallman

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It’s early on in your academic training these days when a teacher refers to the GIGO principle. Simply stated, if you are using a computer, it doesn’t matter how great the machine or the program is if you input bad data. If you put in garbage, it will give you garbage results. Garbage in, garbage out: GIGO.

In flying this is a very real concern, particularly when it comes to programming a GPS. It’s one thing if you inadvertently put in a wrong fix that’s close to the right one, but that’s rare. What’s more likely to happen is that you put in the wrong fix or the wrong piece of performance information, only to suddenly find yourself asking what is going on. When the airplane makes a turn you aren’t expecting, you’ll be scrambling to figure out where the mistake is. It’s great if it happens on the next fix. That usually becomes readily apparent. It’s not so great if you programmed in the wrong fix several legs down the road.

This is an easy mistake to make on a GPS that is programmed with a knob, and it’s an easy mistake to make in a crew environment. I’ll give you an example: I was in a simulator event, and I had the airplane doing exactly what I wanted it to do. Trying to stay ahead of things, I decided to program the climb performance, not registering that the performance I was asking for was for the cruise climb. Asking the airplane to change its profile would cause all kinds of problems on the departure procedure. Following our prescribed procedure, I asked the captain to verify what I was getting ready to do. He did. I hit the button and executed the new plan. To my horror, the airplane began to accelerate and climb like it had a date with Mars.

I quickly turned off the autopilot and autothrottles, and I asked the captain to reprogram “the box” while I hand-flew and kept us out of further trouble. In my peripheral vision, I saw the instructor smile and write furiously. In the debrief, we got kudos for catching the problem immediately and fixing it, but we also got a reminder that GIGO can happen at any time, at any place. It was a great lesson, and it happened in the sim, where nobody could get hurt.

I’ve flown now for more than 20 years, and I have a litany of such GIGO examples—some mundane, some not so much. What I can say is that I don’t tend to make the same mistake twice, but I’ve learned that I am never going to be immune to this kind of error, which is good, as it keeps me on my toes.

But if you want to see how catastrophic GIGO can be, just look at the report for American Airlines Flight 965, which crashed into a mountain in Colombia in 1995 because of a flight management system programming error. It’s a stark reminder of how quickly things can go wrong, even for an experienced crew.—Chip Wright

Which comes first: flying or ground school?

It’s a classic aviation topic of discussion: Do you start with ground school or flying lessons?

The answer, of course, is yes.

Back in the day, pilots-to-be overwhelmingly sat in a classroom and learned the academic side of flying the same way they learned algebra, English, and history. Courses would run several weeks depending on how many days a week it met, and most students were flying concurrently. Nowadays, so many pilots engage in the self-paced home-study courses that it’s probably difficult to find a traditional ground school.

The advantage of starting with flying right away is that you have a much easier time keeping up your enthusiasm, and besides, flying is fun, so why not do it? The truth is that you can do both at the same time, but you need to learn how to do it efficiently and effectively.

The home-study courses available today are a far cry from what was available even 10 years ago, and they are light years ahead of where they were 20 years ago. Jeppesen used to charge a king’s ransom for a series of video tapes that accompanied the private pilot curriculum. Now, online classes and DVDs have replaced VHS, which means you can go right where you want to study, and better yet, it’s all interactive, which keeps you more engaged. The video quality is better as well. And Jepp being Jepp, they still charge a king’s ransom, but the Kings are still doing their thing as well.

There are some areas of study you should start with right away. Aerodynamics, the FARs, and weather are topics that you can’t get a jump on fast enough. Most people are more weather savvy today, thanks to the Weather Channel and the Internet, but aviation weather is still information intensive, so getting a leg up on it early is always a good idea.

But a few areas of study call for caution when it comes to getting too far ahead of where your training is. You should spend a lot of time reading, watching, and studying all of the maneuvers. However, don’t jump into trying to understand all of navigation until you are ready to do your cross-country flying. In more modern aircraft, you may already have a bit of proficiency with the GPS since you use it all the time. In older airplanes, it may just be you and your VOR indicators. I am a firm believer that you will be a better pilot—you’ll certainly be more knowledgeable—if you can do everything the old-fashioned way, and that includes using a manual E6B. After all, it doesn’t ever need to have batteries replaced. As for the panel-mount GPS, a good instructor will take the time to show you all the ins and outs you need to know as you need to know them.

When getting ready for your knowledge test, don’t do it by just memorizing all of the answers. Make sure that you understand the theory and the concepts discussed in each question. Be able to answer them using what you know, especially weight and balance and navigation questions. Some of them are indeed rote memorization (the FARs), but make sure you really know the material and know where to find it!

Learning all that you need to know can seem daunting, but if you break it down into chunks, it is much more manageable. Yes, you can fly before you open a book, but if you combine the two, you will have more effective learning and have a more enjoyable training experience.—By Chip Wright

The best instrument there is

When I first started flying, I used to hear a lot of old timers tell stories about navigating with NDBs and the four-course range. VORs were the sexy new toy of the future. I still didn’t understand how one could safely navigate across the ocean, since VORs didn’t exist on water. I knew that the concept of taking star sightings existed, but I also knew that it was premised on a clear night. Conceptually, I think I knew that the speed of jets would make such triangulation difficult, but not impossible. It also didn’t dawn on me that not every nation in the world could just lay out VORs willy-nilly the way the United States did.

I also heard a lot of stories about the development of the flight instruments. Early versions of attitude indicators and directional gyros were primitive by the standards I was used to. The radios themselves were not always very good. It seemed like there were two classes: top-of-the-line Bendix-King…and everybody else. The Cessna radios were pretty good, but they didn’t have any of the “cool” features like flip-flop windows, DME, and the like. DME, by the way, was some kind of cool. Garmin rules the radio world now, it seems.

It wasn’t long before I began to follow in earnest the homebuilt movement. Kitplanes were just beginning to spread in great numbers—early RVs, Glasair, Lancair, and Kitfox dominated the advertising—and they also spawned a great deal of innovation that we now take for granted. A lot of the modern avionics that cost truckloads of money got started in the experimental arena. Certification wasn’t nearly as stringent, and the rapidly improving computer technologies (both hardware and software) invited a great deal of experimentation. A lot of the inspiration was drawn from airline and military “stuff,” but much of it was simply new. The cost was much lower than it would have been had everything been put through the gamut of FAA testing. It was clear that the homebuilders were leading the way. Nowadays, new airplanes with “glass” technology are taken for granted.

GPS, of course, has changed everything. I personally miss the days when pilots learned the intricacies of aerial navigation not just to pass a written test, but because their lives depended on it. But GPS simply makes a mockery of pencil-and-paper travel. With GPS, you don’t need to call Flight Watch for winds aloft; the heading for the nearest airport is a button push away; and the moving map makes a paper sectional seem quaint…but I still like the paper chart.

NDBs are relatively rare, and the GPS overlay approach can provide lower minimums. Other things long on a pilot’s wish list were an RMI, an autopilot, loran, weather radar, and better “orange juice cans” for the Cessna series. Today, such items have either been leap-frogged or accomplished.

But the most important instrument in the plane doesn’t get much attention. It isn’t fancy or sexy or sold by women in bikinis. It is, however, the cheapest in terms of bang for the buck, and it doesn’t let you down.

As fast as computers are, and as nifty as Nexrad weather is; as efficient and reliable as a moving map is; as handy and helpful as a TCAS display is; the fact is that nothing on an aircraft—or even a spacecraft—can hold a candle to the value and utility of…the windows.—By Chip Wright