13 min read

When ADS-B traffic uplink was announced, there were great expectations for what it could do to improve safety, specifically, to reduce mid-air and near mid-air collisions. After some years of flying with ADS-B traffic, my expectations have been, shall we say, down-sized. It’s nice to think that improvements are easy, but there are real world constraints.

Please note that while some features of some products are discussed below, this article is about ADS-B traffic displays in general and is not a product comparison. And if I got some product details wrong…

Expectation 1: Reducing Midair Collisions


Portable ADS-B receivers mean more pilots than ever before are flying with traffic on their screens.

There’s a lesson from thirty years ago that ADS-B traffic display designers seem to have missed. When the airlines got TCAS (Traffic Collision Avoidance System) in the late 80s, the hope was that it would solve the problem of midair collisions. While TCAS has indeed saved lives, one of the lessons learned was it wasn’t enough to just toss hardware into the cockpit and expect the pilots to figure out what to do with it. TCAS was not a stand-alone system, rather, it was part of the larger system of airplanes, airspace and ATC. In particular, when TCAS gave resolution advisories (commands), both flight crews needed to follow TCAS and ignore any ATC commands. Eventually that became standardized, but there was at least one mid-air collision in which one airplane followed TCAS and the other followed ATC.

ADS-B now gives traffic data but the question is, what are pilots supposed to do with that data? ADS-B does not give resolution commands, nor do ADS-B cockpit displays interact with ATC. When ATC asks the pilot to report traffic in sight, that means visual, not ADS-B. There is no pilot/controller terminology for ADS-B. Is ADS-B just another system tossed into the cockpit that the pilots are supposed to figure out on their own what to do with?

There are new regulations requiring drones to have position reporting equipment on board. It remains to be seen if the TCAS mistake will be repeated yet again, with drones showing up on cockpit displays as raw data with the expectation that the pilot will have time to see it and figure out what to do with that data.

Expectation 2: Aid to Spotting Traffic

In my airplane, I can display ADS-B traffic on two different kinds of screens. One is analogous to a radar scope. Fully zoomed in, the screen will show runways, but otherwise, no background at all. This means that the display doesn’t help the pilot look for a target over a specific area, like on a final approach path.

Worse, that radarscope-style display shows all traffic around the airplane. Traffic behind the airplane is often irrelevant, and dedicating screen space to unimportant traffic means less screen space for important traffic. Yes, there is the case of traffic overtaking from behind that needs to be considered, but the key measure of threat traffic is not how far away it is in distance, but how far away it is in time. ForeFlight, for example, displays traffic based on distance and on time. I’ve read that in Australia, arriving traffic calls state minutes to the airport, not distance.

Other kinds of cockpit screens that can show traffic have different kinds of map backgrounds, but those map backgrounds can have enough background clutter that traffic symbology can be hard to spot. Zooming in on the display seldom increases the size of the traffic icon, so the targets are still hard to spot.

FltPlan Go traffic

Sometimes more information is just distracting.

Especially in the vicinity of an airport—where collisions are more likely—what would be best would be a background designed specifically to help in spotting traffic. That background should show airports and runways, extended runway centerlines, and maybe a very few prominent ground features like rivers, maybe not. This is a different concept from tossing ADS-B traffic icons onto an existing map not designed for spotting traffic.

Yes, when a map is shown and is primarily being used as a map, showing traffic on that map is useful. However, that’s a different case from a screen designed primarily to show traffic.

It’s not that easy, though. At the high end, there may be standards that displays must conform to, and some vendors may have compatibility to maintain across all product lines. I think this is a solvable problem, but then, I’m not in charge of implementation or convincing the regulators.

Expectation 3: Aural Alerts

A human factors challenge is what and how much information should be conveyed by voice and how much by a warning sound. That topic is far beyond the scope of this article, but the bottom line is that voice alerts are too compelling to use casually in the cockpit as they can distract the pilot from other tasks. Also, voice alerts can and have blocked radio communications. Recall that TCAS (airline level Traffic Collision Avoidance Systems) give voice notifications but on the first Traffic Advisory say only, “Traffic, traffic,” not all the details. And TCAS Resolution Advisories are similarly terse. Sometimes less is more, especially when it comes to voice alerts.

Expectation 4: All Traffic of Interest is Displayed, Part 1

Many ADS-B traffic displays display traffic only within a selectable altitude band. For example, jets thousands of feet up in the flight levels are appropriately not displayed. This altitude band concept works satisfactorily in cruise flight for us low performance GA types, but it doesn’t work well around busy airports. Here’s why.

Around an airport, an ADS-B display should show all traffic of interest, i.e., most all traffic.

Traffic filter

Traffic filters are a double-edged sword.

When I’m in the pattern at my local airport with Class C airspace, ADS-B won’t show incoming fast jet traffic until it’s within the altitude band selected on my traffic display, even though that fast jet traffic is already talking to the tower. Sometimes ADS-B shows traffic talking to the tower, sometimes it doesn’t. Sometimes I can count on ADS-B to show me all the traffic of interest, but sometimes it won’t.

The “solution” is for the airborne ADS-B system to look for fast moving traffic descending within, say, 20 miles of the airport. If such traffic appears, the ADS-B system could display that traffic with the reasonable expectation that the traffic is inbound to the airport and will soon be within the normal altitude band.

Here’s the rub: not all the airliners have ADS-B Out. If they don’t have it, the ADS-B uplink system will only send traffic within 3500 feet of my altitude, only slightly larger than the 2700 foot plus/minus altitude “Normal Band.” It would still be worth it, says I, for ADS-B equipped jet traffic, like bizjets. That data could come via ADS-B air to air.

Yes, it is possible to reset the altitude band of the ADS-B near the airport, but that’s extra work at the wrong time and would show much more traffic than is of interest.

Expectation 5: All Traffic of Interest is Displayed, Part 2

A few months back, I was in cruise flight, fat, dumb and happy with no traffic on the ADS-B screen. ATC called and reported traffic at three o’clock, altitude unknown. Sure enough, over at three o’clock, at my altitude, was an older plane, possibly not even transponder equipped.

I had started to get into the habit of expecting ADS-B to show me all traffic, but… If there is threat traffic around, I want ADS-B to tell me about it, and not to disregard it if that plane is not ADS-B equipped.

Expectation 6: The Screen Will Always Be Readable and Meaningful

Here are some screen shots taken over the past few years:

Here’s why predictor arrows necessary! Pilots don’t have enough time to watch the screen to determine relative velocities and collision threats.

Better, but… some of these are irrelevant if the pilot continues straight ahead, especially if groundspeed shows that my plane can’t catch them or that they can’t catch me. Those irrelevant targets increase workload and potential for error. Note how much of the screen is reserved for traffic behind, which is not a factor. Some targets are filled in, some are outlines. That too-subtle distinction does not reduce screen clutter. In the traffic pattern, however, it can be useful to see planes behind you.

Can you find the traffic? There are two planes shown…

This map display is useful as a map but not so useful as a dedicated traffic display, particularly when zoomed out this far. Some targets are not threats and are distracting clutter, meaning more workload to interpret the display. Note that airport and VOR labels are, for purposes of tracking traffic, meaningless clutter. These targets are displayed with motion relative to own ship, a Garmin patent. (The symbology on this screen shot is not consistent with the most recent Pilot’s Guide.)

Here’s what a good traffic display background might look like, but this is not a default screen, this is a manually decluttered ForeFlight screen on a tablet.

To revert to a “regular” map background, all the map symbology has to be turned back on manually, one feature at a time. ForeFlight has no concept of stored screens, unlike many panel-mounted avionics. Note the use of color to show threat levels. But at Boeing, a rule was to never use color alone to convey information, and this display violates that rule. Also note that target aircraft motion is displayed relative to the ground, not relative to own ship.

A full traffic pattern and then some at Prescott, AZ. No wonder I’m hightailing it out of there…

Expectation 6: ADS-B Traffic Improves Traffic Awareness

Sometimes no, sometimes yes.

Sometimes ATC will call out traffic by aircraft type, distance and relative bearing. ADS-B will display an N-number, so I’ll ask ATC if that traffic matches the N-number on the ADS-B display. That won’t meet ATC’s requirement for visual identification, but it will let me get benefit from the ADS-B display.

And again, there is no terminology with FAA-approved significance to communicate to ATC that I am tracking traffic on ADS-B.

Here’s an idea: suppose active N-numbers were stored in the airborne ADS-B units, paired with aircraft type? That would reduce some of this N-number / make / model Q&A. This wouldn’t necessarily be perfect, of course, with an obvious example being Skyhawk versus Cessna 172. Space limitations on the display might require terse identification, like C172. Another possible error source is changed N-numbers. If research shows that problem to be significant, maybe N-numbers could change on the same 28 day cycle as chart data. But in any case, the key to success will be to make the information pilot-centric and not to just throw more information over the fence for the pilots to figure out what to do with it.

There’s hope, however. The current Rev B ADS-B standard is being replaced with Rev C, which will allow four times as much data to be sent from the airplane. No surprise, there are hundreds of proposals on what to do with that extra payload, as it’s called, including weather downloads from the airliners, or maybe even from little planes like mine. And the new payload can carry multiple kinds of messages. How? Avionics engineers often package data as a label that says what kind of data is being sent plus the data per se.

It is a reasonable expectation that the new ADS-B systems will be backwards compatible with existing systems, but older systems might not be able to send data in the new format—like aircraft type.

Expectation 7: ADS-B Lets Me Fit In Better With Traffic Flow

There are really three classes of traffic that ADS-B can help the pilot with: immediate threats, potential threats, and non-threat aircraft that are traffic to fit in with.

ATC tower

ATC and pilots are not always on the same page when it comes to ADS-B traffic.

Sometimes ADS-B helps me fit in with other traffic, sometimes not. When there is jet traffic landing at the same airport I am, the controller has a plan that I gladly fit in with, most of the time. Sometimes I get excessively large vectors that seem to be more for controller comfort than for any reason obvious to me. And there have been times when I’ve been asked for maximum speed, followed shortly thereafter by minimum speed. Hey, no problem, I’m a big boy.

What is useful, though, is when I’m on final behind a local flight school Cessna 172. When I see their groundspeed, I can make sure that I’m not closing in on them. They might be slow clearing the runway because a student pilot is flying. Again, no problem. Or if they’re flying downwind on the other side of the runway, I can adjust speed to fit in behind or ahead of them.

Similarly, when I’m waiting to take off, occasionally I can tell the tower I can accept an immediate takeoff if the ADS-B shows me the traffic on final. How? From the groundspeed of the traffic on final, I can easily calculate their approximate rate of descent (rule of five) and use that with their altitude to calculate how long till touchdown. In my plane, from clearance to take off to crossing the other runway is 60 seconds. Sometimes, though, it’s an exercise in frustration when an excessively conservative controller slows things down.

Meeting More Expectations for Usability

  1. There are significant increases in ADS-B traffic display usability to be easily achieved with cockpit screen displays designed to aid in visually spotting traffic.
  2. Aircraft type could be added to ADS-B displays. Screen real estate could impose limitations on how many characters are used for the aircraft type, but this idea seems at first blush to be valuable for matching ATC callouts with ADS-B traffic. This idea is one of many candidates in the upcoming new ADS-B data protocol.
  3. Arriving high speed traffic could be displayed around airports, even outside conventional altitude bands. This would work for jets with ADS-B Out, but not all airliners have ADS-B Out.
  4. There may be good reasons why ATC does not care whether a pilot sees traffic on ADS-B or not. If those reasons have been publicized, that publicizing has been inadequate. If there are no reasons, ADS-B traffic could be utilized to improve things for both ATC and pilots.
  5. All traffic should be uplinked to ADS-B equipped traffic, even non-transponder traffic. Not sending traffic information to pilots “just because” wastes ADS-B as a safety resource.
  6. If it hasn’t been done already, the FAA should figure out what pilots are supposed to do with drone traffic on an ADS-B display. Inundating the pilot with raw data can degrade safety, not enhance it.

Acknowledgement: Thanks to Garmin media relations for access to their ADS-B guru for technical information.

Ed Wischmeyer
24 replies
  1. Ken T
    Ken T says:

    Good article. I certainly agree with the idea that navigating by sectional makes it almost impossible to see ADSB traffic. That’s why I virtually always fly with the aeronautical chart only. It gives me a nice, clean slate to see all targets easily.

  2. David Ward Sandidge
    David Ward Sandidge says:

    Good article. Very thought-provoking. Because I’m still legally a flight instructor, I fly with a friend occasionally in his C-177 when he needs a checkoff of some sort… Flying around below ten thousand feet AGL in the Phoenix, AZ vicinity with ADBS-B in is about as nerve-racking as trying to go north for the weekend on a scalding-hot Friday on Interstate 17 at five p.m.. About every ten seconds or so he’ll yell out quite anxiously: “We have traffic, such-n-such o’clock at our altitude. HE’S COMING RIGHT AT US!!” Immediately, I have visions of a sudden and violent end and begin spinning my head like a top until I ask him, “How far away?” He’ll calculate for a few seconds and then reply, “Oh, about twenty miles.” Good grief!! At my age I can’t spot a pregnant C-5 at twenty miles!! Then, just as my blood pressure begins to settle down, he’ll sound the next alarm. Sometimes I wish we’d never heard of ADS-B. I suppose it is nice to have, but even with it telling me where the traffic is I hardly ever see anything at all. Makes me think that being fat, dumb and happy back in the day wasn’t so bad… So, I guess I’ll just stick to my Merlin flying in the high teens to mid-twenties. There’s hardly any airplanes up there anymore – maybe an occasional King Air, or a huffin’ and puffin’ Mooney… Generally, the air is much smoother at 22,000 feet than the air below ten-thousand and the air above FL300. I used to get frustrated at the airline because of the persistently rough air starting at about 50 feet before leveling off at your chosen cruise flight level – no matter what that was… Over the past year – and about 600 hours of flying – I would estimate that I have had no more than five conflicting traffic alerts up at the 18,000 to 24,000 feet altitude range. But don’t tell anybody, would ya? I’m not ready to fight the high blood pressure thing again.

  3. Kim Hunter
    Kim Hunter says:

    The fact that many airliners are invisible to ADS-B is by the airlines’ design.

    Many years ago the airlines, and their lobbyists, went to war against the FAA’s WAAS GPS implementation program. Two prominent reasons were; 1) they saw most of the benefits going to GA, and 2) they did not want to spend the money (or down time) upgrading their existing GPS-based FMSs to WAAS standards. The airline lobby was able to strong-arm the FAA into granting airlines a 5 year extension to upgrade their fleets to WAAS-based ADS-B.

    The major carriers have no intention of upgrading any existing FMS. Instead, they are relying on newly purchased aircraft, which come equipped with WAAS and ADS-B, to gradually phase out their older non-compliant airframes. If some of these ‘invisible’ ships are still flying when the extension runs out, the airline lobby will demand another extension. The FAA will surely comply.

    • JOhn
      JOhn says:

      The next question then becomes… will ‘LEGACY’ rotated out of the Airline fleet and sold to freight companies EVER be equipped with ADSB-OUT? FWIW, that Boeing 737-200 that ditched shortly after departing a Hawaiian airport was 60 years old!!! Will these legacy aircraft become ghosts that continue to degrade the much lauded aviation safety benefits touted by the FAA and others when ADSB-OUT was sold as “the” answer to MAC?

  4. Ed Wischmeyer
    Ed Wischmeyer says:

    In this article, I hinted at but had not yet fully realized that there are two (at least) major categories of ADS-B traffic use:
    * Around the airport, both own ship and targets are navigating relative to the same fixes, namely, the airport environment (including extended runway centerlines). In that environment, relative target motion is less important than the target location referenced to the airport environment, because the underlying structure of traffic patterns and approach and departure paths makes it easier to track targets. Relative motion display is not only irrelevant but also distracting. Having a background with appropriate landmarks (runways, extended centerlines, maybe coastlines) is very useful for tracking traffic.
    * In cruise flight, relative motion is much more useful because there is no underlying structure to help the pilot anticipate the motion of the other plane. Geographical landmarks will be much less useful, especially at altitude.

    The next question is, of course, how to switch the two display types without unnecessary workload.

  5. Vic Myev
    Vic Myev says:

    Thanks Ed. Flying in the Phoenix area, I occasionally have two problems with ADS-B. One I call “ghosting” where a target suddenly pops up out of nowhere and then just as suddenly disappears. I believe this is an issue of mountainous terrain and low altitudes, The other one is less common but more scary- the display and callout will sometimes show a target at say 2 o’clock 2 miles, when the actual plane is at 10 o’clock and 2 miles, a kind of mirror image. We have verified the correct position of the aircraft both visually and on the Sentry, after wasting valuable time looking in the wrong place. The mirroring seems to be a hardware/software problem, which was fixed on one of our Cirruses for about $7000, after much back-and-forth with the factory. My students and I now always carry a Sentry or Scout as a backup.

  6. Herny Kuhlman
    Herny Kuhlman says:

    ADS-B and I were friends off and on. In the early days, when few planes had ADS-B and the operation was erratic-at the worst times, we mostly ignored it (airline flying). But as time went on, the information at cruise was “nice to have,” but TCAS was the mantra “Must Have” system to avoid mid air’s. However, in later yeas of flying before my retiring in 2013, ADS-B became quite useful, mostly in he terminals area. Very helpful indeed. At busy airports like “overnight package delivery airlines with large numbers of planes arriving into a hub at the same time, traffic grew to fifty or more — headed to the same outer approach fix. ADS-B highlighted the most applicable targets which could be switched with a button. The ability to see what controllers were seeing, so to speak, synced up the plan on how aircraft were sequenced between each other. A great feature showed the difference in speed closer rates to allow adjustments, especially after the controller says, _____ do you see the traffic at 2 O’clock, three miles, that’s your traffic, cleared visual approach to follow that traffic.” Having speed delta info was nice. As for the dozens of other targets outside our immediate area, we ignored them for the most part. Future generations will improve. Hopefully they will not clutter the display by adding data not important to the task– Awareness of only information relative at the moment. Thank You,

  7. Robert Patlovany
    Robert Patlovany says:

    Let’s consider Ed’s Expectation 1, “… there was at least one mid-air collision in which one airplane followed TCAS and the other followed ATC.” I bet this refers to the 2002 German midair collision. Supposedly, both were required to obey the hemispherical cruising altitude rule (HCAR). However, the one flying 004 degrees was actually at an incorrect westerly altitude specified by HCAR that was not allowed for one flying slightly easterly at 004 degrees. I have yet to see a single accident report that identifies this pilot HCAR compliance human factors error as “the root cause”! That makes the 2002 German collision like the 1997 collision west of Namibia, where the German pilot was flying at a slightly easterly altitude (mostly headed south) while using an HCAR altitude reserved for a westerly heading. The unrecognized (by the FAA and ICAO) BIG DEAL is that all of these accidents were primarily due to unsafe flight in artificially thin cruising altitude layers, forcing aircraft to unnecessarily imitate boats flying on Lake 10,000′, Lake 11,000′, Lake 12,000′, and so on, whether at IFR or VFR cruising altitudes. This boats-on-a-lake (BOAL) layered flight root common cause failure embraces relevance to the 2006 Brazilian midair collision, where ATC ordered the doomed head-on pilots to fly at exactly the same altitude–and two brand new aircraft with the latest TCAS ran into each other within 50′ of an airway centerline with GPS precision flown by autopilots!

    The designed-to-be-unsafe BOAL HCAR strategy is 100% dependent on far less reliable, far more costly, lower safety priority strategies (like TCAS and ADS-B, not to mention ATC remote-controllers with radar and radio networks) discouraged as first-priority safety controls by Chapter 3, Section 3.6, Table 3-7, Safety Order of Precedence, in the FAA System Safety Handbook published on December 30, 2000, two years earlier than the 2000 German midair. While two years may seem like too little time to fix this BOAL problem, the FAA’s own Safety Order of Precedence was basically copied from MIL-STD-882B, System Safety Program Requirements, Section 4.4, System Safety Precedence, March 30, 1984. Therefore, the FAA and its ICAO peers had ignored the system safety engineering state-of-the-art for cruising phase midair collision safety order of precedence for 18 years at the time of the German midair disaster, as foreshadowed by Leighton Collins in the 1960s, and by my 1997 Risk Analysis article proving, with 2000 corroboration by NASA Ames Research Center, that purely random altitude flight is at least six times safer than BOAL flying. In other words, in a safety order of precedence context, it is far safer to cruise at random altitudes that automatically eliminate flight path intersections–than to depend on lower order of precedence, high cost, low efficiency cockpit toys, like TCAS and ADS-B. One of my Colorado pilot commenters noted that he spent $10,000 on a panel upgrade for ADS-B. He reports that 100 percent of his head-on conflicts are alerted by his expensive ADS-B after the head-on threat is behind him.

    Leighton Collins wrote four Air Facts articles in the 1960s that pillory the FAA for the HCAR formula in particular ignoring FAR SAFER 1928 technology using zero cost randomized flight obeying a FAR SAFER altimeter-compass cruising altitude rule (ACCAR) that randomizes cruising altitudes as a linear function of random headings using a hypothetical or imaginary compass rose sticker on the altimeter glass to match the altimeter 100-foot hand angle (on the sticker) to actual magnetic compass heading. For anyone interested in the gory details of this decades long FAA and ICAO technical error in system safety order-of-precedence ignoring zero-cost random altitude flight with ACCAR in favor of BOAL flying with expensive toys foolishly trying to fix the HCAR designed to cause midair collisions, visit https://tinyurl.com/y24wvzaf or contact me at [email protected].

    • Phil Hertel
      Phil Hertel says:

      Thanks for the Leighton Collins’ articles and other data. I’ll be studying it in detail, because as a former “working pilot” and CFI-I, I too see ADSB as a tool that needs a lot of perfection of “human factors” design elements to reach its real potential as a safety enhancement.

  8. Stephen Phoenix
    Stephen Phoenix says:

    I think the reason that ATC might not care if you claim to see traffic on ADS-B is that it may be adding an extra layer of liability on them if you happen to be looking at the wrong target. That scenario can and does happen with visual callouts also, of course. But it might be a bigger problem with electronic displays and many targets to choose from.

    Overall, I have found ADS-B to be worth the money. I am certain that it has saved me from having a bad day at least twice in the four years I have been using it.

  9. David Dickins
    David Dickins says:

    This is a really excellent article about complex topic that really gets pilots fired up! Like the author, I had great expectations that ADS-B would become my safety net and eliminate mid-air anxiety. So far it is a mixed blessing. I’ve had a few situations where seeing the Scout traffic on my iPad helped greatly in terms of situational awareness e.g. approaching a busy non towered airport or knowing that a fast mover was crawling up my tail closing at 50 knots relative airspeed at exactly my altitude (in a 150, everybody is a fast mover! My confusion over ADS-B is why the system developed over more than a decade at huge expense is still dependent on ground stations? Other countries like Canada are late to the game but are committed to a satellite based system that seems much more advanced in terms of technology. Altogether a mixed blessing but I’ll take some traffic over non at all, recognizing that it is not the full picture.

  10. TedK
    TedK says:

    Who is the threat? It is the aircraft that is on an unchanging bearing and decreasing range. Mariners have a term for this CBDR, Constant Bearing Decreasing Range. My ADS-B has a cockpit display in relative mode. I watch for CBDR traffic. Generally a minor maneuver, to put my nose on them solves the conflict. Like I learned when driving Destroyers in tight maneuvering formations, if your bow is pointed at their stern, you ain’t gonna trade paint.

  11. Kent D Nicholson
    Kent D Nicholson says:

    Sorry, Ed, but this article seems to go out of the way to disparage ADSB traffic. I find the exact opposite to be true – with Foreflight and “Hide Distant Traffic” selected, I find it an easy to visualize and highly useful system. I can’t believe how much traffic I see on the display (both called by ATC or not) that I never see visually – makes me wonder how much I missed before the technology existed, including two close encounters that would have been obvious with ADSB. Is it perfect? No, but nothing is.
    As a CFII, I find the benefits of ADSB traffic far greater than any little imperfections, especially in the vicinity of airports while trying to conduct practice approaches. As a retired ATCS, I was around for the implementation of TCAS and the associated growing pains, but the system was eventually excised of most of the bugs, and safety improved.
    I have found ADSB traffic to be worth the price of admission since installed in 2017, and that is just a bonus over the weather information we also have available to us.

    • David M Campbell
      David M Campbell says:

      I kind of thought the same as Kent. Foreflight with distant traffic hidden seems to address most of the downsides pointed out. It has the speed/direction arrows as well with your background selectable. I often hear and sometimes say to ATC when alerted to traffic – “See them on the screen, no visual yet”. A huge increase in situational awareness. I do think it is important to point out – as this article does very well – as with any technology there are limitations. The users do need to understand their equipment and the system as whole for the most benefit.

  12. Rick A
    Rick A says:

    Excellent article. One of things I learned a long time ago the mind set of engineers is that if it can be done, it should be done. As one myself, I understand it. But when presented with a new thing, my job as Chief Engineer was to ask why should it be done? Seems like that question wasn’t asked enough in the evolution of ADS-B.

  13. JackE
    JackE says:

    So we have pilots with their heads buried in multiple iPads, smartphones and cluttered panel glass displayed, with three to eight Go Pro’s stuck on multiple windows, blocking their already limited view (on most GA aircraft), and the problem is airliners don’t have ADS-B out?

    • Tom Curran
      Tom Curran says:

      Amen! That, and pilots that really, honestly, actually, respond to ATC traffic advisories/call outs with “Got em on the fish finder”….(if they have a mid-air, at least they’ll be relaxed).

  14. Vince Massimini
    Vince Massimini says:

    Hi: Nice article, but full of your assumptions and errors. For example, please let us know what airliners do not have ADS-B out–it is required in Class B, C, and E (above 10000 MSL)–that will include all of the current jets and turboprops. Most of your comments apply to whatever avionics you have–not to the ADS-B system. For example, my Garmin only annunciates “Traffic” aurally. That is not going to block comm. I can select a restricted traffic view or a broader traffic view. I can see high-speed traffic miles from the airport. And, ADS-B is a FAR more capable traffic advisory system than TCAS (including TAWS A, B, or C).

    I agree that the system is not as rigorous as TCAS on collision avoidance. It was never intended to be–and it would be far too costly if we tried to turn it into TCAS. ADS-B does not replace see and avoid–it is only an assist.

    My suggestion is to work with display vendors to implement improvements.


    Vince Massimini
    Kentmorr Airpark MD (3W3)
    [email protected]

    • Kim Hunter
      Kim Hunter says:


      The answer to your question is that any aircraft operating under part 121 with an FMS that predates WAAS GPS has gotten a 5-year pass on implementing ADS-B. If they are still flying after 5 years the airline lobby (Airlines for America), and their allies in Congress, will write another extension.

  15. ray bohrer
    ray bohrer says:

    great article. My recent experience was being handed an ipad/foreflight combo , and told to watch for trffic in a busy training environment. Your example of a nearly unreadable display is a duplicate of my experience, (not to mention a closer than comfortable plane flying over us near final, that was not noted by my planes pilot, who was trying to read the ipad display) Looking out the window still works in a busy environment. I had not flown with the adsb display before, so should have been briefed more…..just some ideas for discussion.

  16. Ed
    Ed says:

    ADS-B has it good points, but as with all technology, it has it’s pitfalls and traps. The article is a good, honest look at the pro’s and cons of ADS-B, but misses a major one, that is the FAA’s ability to use ADS-B as as a means to create enforcement actions. There are already cases on the books where pilots committed some relatively minor (and some not so minor) infractions, that the FAA enforced, simply because the ADS-B data “had ’em dead to rights”. And while a lot of us might say, you shouldn’t have done that anyway, everyone can and does have a bad day on occasion. Now they have a “Traffic Light Camera” in the sky, they simply won’t be able to resist using it, which means a lot more enforcement actions. That has put a darker color on what is a helpful technology. The FAA admitted this behavior, when developing the NASA Safety reporting system, which is why NASA runs that database. Now, if you’re the saintly type who never drives above the speed limit, or never rolls ever so slowing through a stop sign, you’re probably ok with big brother sitting in the cockpit, if you’re like the rest of us, a slightly imperfect human, you may have some concerns about getting an unexpected notification for something you might not even realize happened, that had no negative repercussions at all, that previously wouldn’t have been worth anyone’s effort to investigate or write up an action for, but with ADS-B and some computer software, will just be an automated system generating revenue and reportable actions – both of which are good for the FAA, but not really helpful for aviation or pilots in general. And as has been demonstrated repeatedly, expecting any sort of commonsense or moderation in government action is pretty unrealistic.


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