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View Full Version : Pilot Reaction to an ADS-B Traffic Advisory


Tango Mike
08-21-2014, 04:39 PM
The "Flawed" discussion in this Safety forum is an instructive resource that has identified for me a personal need to understand the ADS-B system better. The technical aspects are confusing, to say the least, and it will take me some time to sort through it.

In the meantime, I'm not seeing much in the way of discussion here or elsewhere, though I may be missing it, about an issue that frankly worries me more than all the implementation issues combined.

Underlying all the technology, whether it be the early contribution of transponders and radar to safe separation of airplanes or the Next Gen concepts being implemented, "SEE AND BE SEEN" (SABS) is the ultimate defense against mid-airs unless the view out the windscreen is obscured. Which, for many reasons, creates a situation with less likelihood of encountering another airplane in the same piece of sky.

For the purposes of this thread, lets assume VFR conditions, under IFR or VFR flight rules with or without flight following, one pilot flying alone or with a passenger who will be of no help because he or she is physically and mentally plugged into an iWhatever.

"Traffic," says the box.

The first reaction of any pilot is to go head down to answer the question that trumps every other consideration at that moment: "Where the heck is he?"

You need to know clock position, range, altitude above/below, and lateral and vertical trends. With that position in three-dimensional space in mind, you bring your eyeballs to bear for the tally ho.

But there's nothing there. At that instant, the "why" means nothing as you most probably glance back inside to take another look. Then maybe that sequence repeats a few times, and all the while you've not visually cleared any other piece of the sky. A non-ADS-B airplane could be barreling down on you from another clock position while your attention is tunnel-visioned elsewhere, and SABS has gone on holiday.

What about two pilots in the airplane? Any discussion prior to flight about who does what in the event of a traffic alert?

In a 2-crew member airplane, I always briefed copilots that the pilot flying the leg (PF) never looked inside the cockpit in response to a traffic advisory or alert. Heads up, the PF followed the verbal description from the pilot not flying (PNF) to put eyes on the threat. If the threat of collision increased, click off the autopilot to hand-fly the airplane and be ready.

I submit that far too many pilots with ADS-B in the cockpit approach the collision-avoidance problem with the same attitude evidenced by that most useless of calls at a non-towered airport:

"Any traffic in the pattern please advise."

That's an example of the big-sky theory gone berserk. When you hear that, you know almost to a certainty that if no one answers, the pilot who said it concludes, "I'm alone in the pattern." SABS gets shoved under the seat. Never mind the original-equipment Cub shooting touch and goes. Or the pilot on the wrong frequency. Or with the volume turned down. Big Sky Airport, here I come!

Here's the ADS-B equivalent from my own repertoire of experience.

Non-towered airport with an award-winning $100-hamburger diner at opening time for lunch, a beautiful Saturday after a couple of weekends of lousy weather, aviators eager to slip the surlies and order food from at least three of their favorite food groups: burgers, fries, and malts.

A pilot reports on final at, get this, 30 miles out. That should have been a warning to the rest of us to clear out.

The standard rectangular pattern is nearly a zoo, with airplanes at all four corners and more trying to squeeze in.

In the midst of this, the straight-in idiot continues to report decreasing distance. The last call I remember hearing was about 3-5 miles. The number one airplane established in the pattern is on downwind approaching base. He calls the straight-in twice asking for his distance. No reply.

I was number two behind the guy about to turn base and couldn't see anyone on final. Neither did the base traffic as he called and started the turn. About half way through on base, he sees the straight-in traffic fly close underneath him, forcing a go-around.

On the upwind, the go-around pilot very politely suggested to the straight-in fool that he should pay more attention to traffic established in the pattern and make sure it's clear when electing to fly a straight-in.

And here's the reply: "But I didn't see and traffic on my ADS-B."

I guess all those calls were from another airport.

Rest assured, I appreciate the fact that this is an absurd (but true) example of a pilot who has a lot more wrong with his decision making than interpretation of ADS-B traffic.

That said, it's not hard to envision that among the total population of aviators out there flying with this new system for enhancing safe separation, a significant and more dangerous percentage will be less likely to embrace SABS as the ultimate and final defense against the mid-air bending of metal because of two things:

1) Spending more time head down because of system alerts, and 2) Making the erroneous assumption that if nothing is showing on their magic screens, "It'll probably be all right."

Personally, as an aviator with about a half-century (thankfully) of no mid-air-collision flying behind me, I'd like to see a lot more awareness and discussion of the potential for ADS-B to increase the likelihood of near misses and collisions when not used properly. Add to that the technical deficiencies illuminated in the "Flawed" thread, and we've got a lot of work to do.

Tosh

dtw_rv6
08-21-2014, 04:58 PM
I wonder how many people know that the assertion by ADSB vendors "You must equip by 2020" is wildly inaccurate. Under current regulation, it will be perfectly legal to fly my aircraft without any of the whiz bang Next Gen hardware, just as long as I stay outside of areas that currently require Mode-C. From a pure square footage comparison, there will be more places I don't need ADSB than will require it. Talk about false security. Its a big sky until two of us end up in the same place at the same time.

Tango Mike
08-21-2014, 05:09 PM
I wonder how many people know that the assertion by ADSB vendors "You must equip by 2020" is wildly inaccurate. Under current regulation, it will be perfectly legal to fly my aircraft without any of the whiz bang Next Gen hardware, just as long as I stay outside of areas that currently require Mode-C. From a pure square footage comparison, there will be more places I don't need ADSB than will require it. Talk about false security. Its a big sky until two of us end up in the same place at the same time.

Point well taken, and the corollary is that the airspace not requiring it will be heavily populated with ADS-B-equipped airplanes. They won't all rush off to fly where it's required.

Now the pilot of the non-ADS-B-equipped airplane, who relies on SABS as the final defense, is mingling with ADS-B overly confident pilots who will be given no proximity warnings from non-participating traffic and are expecting to have an edge in the defense against becoming a statistic.

GalinHdz
08-21-2014, 05:15 PM
When flying in VMC conditions, SEE AND AVOID will always be the most accurate anti-collision system available to an aircrew. Much more important than ATC, ADS-B, TIS, TIS-B, TCAS or any other traffic avoidance system will ever be.

:cool:

DanH
08-21-2014, 05:19 PM
Thank you Tosh. I couldn't agree more if I had written it myself.

http://i59.tinypic.com/20jmkjb.gif
"God 'Elp All Of Us"

flightlogic
08-21-2014, 05:20 PM
Use it ALL. Eyes most... and learn to focus away from the nearby stuff.
Passive transponder (radar detector types...Zaon)
And ADS-B. Passenger briefed to watch for moving objects.
Radio calls (with discrection) and don't bother with N numbers at uncontrolled.
Color and type is easy to remember.
LISTEN for a few miles (on a second radio if available) to get a picture of activity where you are going.
The weather delivery is nice. At 12K over the Sierras today.... I was getting info from 5 ground stations at one time. The furthest was 149 miles away.
I knew all the altimeter settings, Airmets, and winds from every airport I could get to with my fuel level. I am pretty sure 2020 will slip too. Not to worry too much at this point.

vlittle
08-21-2014, 06:46 PM
Here's a comment I made on the Dynon Forum about traffic detection:

...
ADS-B, in my opinion is primarily for the benefit of ground stations. Because the FAA introduced the UAT as an option in the US for ADS-B out and ADS-B in, there is a significant risk that some aircraft will be blind to other traffic in non-radar areas or other countries (Canada for example).

Systems that use 1090-ES for ADSB-out constantly 'ping' their position, even when outside of radar surveillance. These pings can easily be picked up by other aircraft, using passive traffic monitors, such as the Monroy ATD-300+. If everyone is using 1090-ES then it's easy to provide reliable anti-collision detection in remote areas, such as mountain passes that may have a lot of VFR traffic.

Systems that use UAT for ADS-B out will not be detected by these passive traffic monitors. If the majority of aircraft are using 1090-ES, then pilots will tend to depend on traffic reporting from their traffic monitor and forget that there may be UAT traffic in the area.

It makes more sense to standardize ADS-B out as 1090ES and allow ADS-B in to be either transponder or UAT based.

Unfortunately, that's not the way the system in the US is designed. Therefore, I think that it makes more sense to build an ADS-B in receiver that will provide both UAT and transponder based reception. That will eliminate the problem discussed above... providing traffic detection in both radar-surveillance area and non-radar areas. Done properly, it will also detect Mode-A and C traffic, similar to the Monroy device.

So my suggestion is for Dynon to make an integrated traffic monitor, capable of receiving Mode A/C, Mode S-ES, Mode S/TISB and UAT-TISB/FISB. This will make it useful in any country and provide traffic avoidance outside of radar surveillance....

Tango Mike
08-21-2014, 07:12 PM
Here's a comment I made on the Dynon Forum about traffic detection:

...
ADS-B, in my opinion is primarily for the benefit of ground stations. Because the FAA introduced the UAT as an option in the US for ADS-B out and ADS-B in, there is a significant risk that some aircraft will be blind to other traffic in non-radar areas or other countries (Canada for example).

Systems that use 1090-ES for ADSB-out constantly 'ping' their position, even when outside of radar surveillance. These pings can easily be picked up by other aircraft, using passive traffic monitors, such as the Monroy ATD-300+. If everyone is using 1090-ES then it's easy to provide reliable anti-collision detection in remote areas, such as mountain passes that may have a lot of VFR traffic.

Systems that use UAT for ADS-B out will not be detected by these passive traffic monitors. If the majority of aircraft are using 1090-ES, then pilots will tend to depend on traffic reporting from their traffic monitor and forget that there may be UAT traffic in the area.

It makes more sense to standardize ADS-B out as 1090ES and allow ADS-B in to be either transponder or UAT based.

Unfortunately, that's not the way the system in the US is designed. Therefore, I think that it makes more sense to build an ADS-B in receiver that will provide both UAT and transponder based reception. That will eliminate the problem discussed above... providing traffic detection in both radar-surveillance area and non-radar areas. Done properly, it will also detect Mode-A and C traffic, similar to the Monroy device.

So my suggestion is for Dynon to make an integrated traffic monitor, capable of receiving Mode A/C, Mode S-ES, Mode S/TISB and UAT-TISB/FISB. This will make it useful in any country and provide traffic avoidance outside of radar surveillance....

At some point before I make a final trip into the big sky, I'd really like to understand the intricacies of your reply.

But in the meantime, I'll reiterate that my intention for this thread was to provide a forum location not for discussing the technical aspects of what will work and what won't and how screwed up it is or will be and how to fix it, but to illuminate an issue that in my opinion goes beyond the nuts and bolts of how the advisories and alerts are generated.

The larger the gap between what the majority of pilots think the system does in terms of protecting them from mid-air collisions and what it's actually doing, the more dangerous complacency becomes.

I submit that from a practical perspective in the cockpit, far too many pilots are going to be adhering less to the SABS concept because they assume that the skies are safer when they have the black boxes that make their aircraft ADS-B compliant.

In VFR conditions, head down is a killer waiting to strike. Luring eyes into the cockpit in the wrong place and at the wrong time will not increase safety. IMHO, readers of this forum and many others, who engage in a collaborative effort to be better aviators, don't represent the majority of GA pilots.

I'd like nothing more to be wrong about that, but I'm not holding my breath.

rbibb
08-22-2014, 04:56 AM
Some people never learn. I did by almost dying. Back when dinosaurs roamed the earth and learning to fly in a non-radio equipped Champ wasn't such an oddity to the celebrated by someone from the Smithsonian wanting to conduct an oral history project interview before you died, I was shooting T&Gs in said Champ at an almost deserted airfield.

Those on the ground heard the radio call said with such obvious pride and sense of superiority announcing that Commanche XYZ (wow radio and retractable gear!) was on a 6 mile straight in approach. Being equally sophisticated and perhaps sensing the potential for a problem, the FBO manager (and airport owner, lineboy, mechanic, flight instructor, and grass cutter) replied back that said Commanche should be aware of no-radio Champ with Student pilot was in the pattern trying to perfect the art of landing a taildragger in the light crosswind that existed at the time - or words to the effect.

Whether said Commanche acknowledged said transmission is a fact lost to history and, in any event, was unknown to me because I was, after all, non radio.

Upon turning final with total concentration on the task at hand I learned the lesson some refuse to take to heart upon seeing said retractable gear of said Commanche in its extended state glide not 6 feet above the windshield of the Champ that, until then, I had not considered might kill me that day.

I went around, gathered my courage, and landed to find an observer (my father) in a spirited conversation with an indignant Commanche pilot who as committed to the position he had done nothing wrong. I suppose if he knew just how close his airplane had came to killing him he might have reconsidered his position.

I learned two lessons. One See and avoid is MY responsibility, and two, some pilots think because they have some technology at their disposal they don't have to abide by lesson one.

Seems like we are about to have to be reminded again.

It was just plain luck my flying career didn't end before my first checkride some 42 years ago...

Pat Hatch
08-22-2014, 06:35 AM
I am reminded of the midair some years back when a high-performance, low-wing aircraft was descending into an airport and overtaking a slower, high-wing Cessna. The Cessna never knew what hit him. I guess I became that high-performance, low-wing aircraft; and as a result of that accident I resolved to always do clearing turns when descending into the traffic pattern. Look out below. See and be seen above all else.

I guess my point is that SABS canít possibly avoid every potential conflict. Sometimes the geometry just wonít allow it, sometimes itís the visibility, sometimes the high performance of a jet versus a slower flying Cub. You have to be aware of this limitation.

I consider ADS-B to be just another tool to use in the avoidance of other aircraft, not to be relied on exclusively nor allowed to be a distraction. Used properly, ADS-B enhances safetyóand for me that is the bottom line.

I flew too many years with TCAS on a corporate jet not to realize the value of this technology. I quickly learned how useful a tool TCAS could be. Yes, there was a lot of criticism when TCAS first came out about the potential for distraction or the false sense of security it might give you. But few will argue with the success of this system over the years or the fact that it has saved the bacon on countless occasions. You could argue that ADS-B is no TCAS, and you would be right, but it comes pretty close. For me itís 2 + 2 = 4. Add ADS-B to SABS and you come out aheadóif you use this tool properly.

But like every tool we initially take up to build an RV, for example, you have to go through a learning curve. I know that every one of you builders out there were much better driving rivets at the end of the project than you were at the beginning. It takes time and experience, trial and error. I am still learning new techniques using ADS-B every time I go out and fly. Thereís a lot to learn, just donít let it become a distraction. Anyway, as Stein says, thatís my 2 cents, hope it helps somebody. Thanks, Tosh, for raising the issue.

Tango Mike
08-22-2014, 06:56 AM
Richard,

We had a saying in fighter squadrons: "There are two kinds of pilots you don't meet very often. Those who have unintentionally hit the ground in an airplane, and those who have hit another airplane with their airplane."

The statement usually accompanied phase briefings prior to the low altitude and formation portions of the syllabus, along with two others. For low altitude: "Remember this, fellas. The best you can do is tie the record." And for formation: "Over 85% of mid-airs in the USAF occur between members of the same formation."

Admittedly, fighter aviation is far more inherently dangerous than a $100 hamburger run, but in both cases, two airplanes can't share the same piece of sky without bad things happening.

The blatant ignorance and sloppy flying I see at non-towered airports when the pattern is busy make me want to turn tail and hold to let things calm down. I don't want this reply to generate a civilian vs. military issue, but it's undeniable that an overhead pattern keeps you within power-off gliding distance of the runway throughout the maneuver. They don't integrate with the standard rectangular pattern any better than the straight-in, but a standard pattern doesn't have to put the downwind, base and final legs so far out that you can't glide to hard surface if need be.

And forget expecting the pilot ahead to touch down close to the approach end and clear the runway for the next guy. Yes, the runway belongs to the airplane on it, but it's not rocket science to fly a pattern precisely enough to avoid passing up one or more turn-offs at many airports. I see this all the time. A pilot lands 1000-2000 feet from the approach end and can't even make a midfield turn off.

At its most basic, my primary concern is the impact of on-board traffic information in VFR conditions at a non-towered airport with a congested pattern. All the technical issues aside, this is a mid-air waiting for a news story.

Thanks again for sharing your experience.

Tosh

Tango Mike
08-22-2014, 07:07 AM
A not-so-tragic low-wing to high-wing encounter occurred a few years ago at an airport in California. The pictures of the aftermath are a jaw-dropping reminder of how lucky these folks were.

Low-wing landing, high-wing taking off, and when they both came to a stop on the runway, it looked like a GA version of the shuttle piggybacked onto a 747.

The high-wing's prop didn't even strike the low-wing's fuselage.

Miracles maybe do happen, but it's probably best not to rely on them . . .

RV7ator
08-22-2014, 08:43 AM
Mike's on the underlying problem - too many head down distractions. Now we have an unreliable "tool" for traffic reporting to deal with. Those I know, and I, know we aren't looking outside as much as we used to, especially if your traffic device is having hysterics over every bug in the pattern at a busy GA airport Saturday a.m. Don't even get me going on the insanity of the latest crop of EFIS' having a little window where you can watch yourself fly. Then post it to You-Tube for fellow narcissist. Digital has unleashed mediocrity.

John Siebold

flyboy1963
08-22-2014, 08:46 AM
...so I'm 15 miles clear of the control zone, radar service terminated, and I'm over our favourite fishin' hole, looking intently at campsites, when my little MRX blinks. ( still partial radar coverage in the area).

My eyes immediately go outside, looking for the target suggested at 500' below, 1 mile....bearing unknown.
I tooled around the area for 15 minutes, never saw him, perhaps a heli-logging operation never above 200', but it sure made me aware that I may not be alone!
Yes, I frequently looked at the display for clues where he might be, but spent 99% of the time doing the SAA ( see-and-avoid) thing.
My focus on the lake below was probably the most dangerous part of the day.

Rupester
08-22-2014, 09:40 AM
This is an excellent thread ... thanks to all of you contributing lessons-learned. Excellent advice herein, as lectured by Professor Experience. It's just too easy to be head down for a bit given all the "do-dads" that can alarm in our EFISs.

Low Pass
08-22-2014, 10:26 AM
Mike's on the underlying problem - too many head down distractions. Now we have an unreliable "tool" for traffic reporting to deal with. Those I know, and I, know we aren't looking outside as much as we used to, especially if your traffic device is having hysterics over every bug in the pattern at a busy GA airport Saturday a.m. Don't even get me going on the insanity of the latest crop of EFIS' having a little window where you can watch yourself fly. Then post it to You-Tube for fellow narcissist. Digital has unleashed mediocrity.

John SieboldI agree. Way, way too many people out there remarking about how they will or have been using the various technologies to identify other aircraft. This is really scary. Not everyone will be equipped and in the system. Not everyone is in the system now. Not all will have 100% functioning equipment now or then.

It's just like the comments that always come up around radio usage. It is not required to use in all airspace and not all are even equipped. I'm a big believer in the new technologies as a supplement. But rule number one is still keeping your eyes open and watching where you're going.

Kind of like the discussions about the "targets" showing on the various devices with people coming and going to Oshkosh. Talk about a situation when you need maximum outside eyeball time!

bpattonsoa
08-22-2014, 10:32 AM
I had an interesting experience the first time my ADSB Skyview equipped RV-10 announced TRAFFIC. I have many more hours in gliders than power. My glider has an audio vario and electronic nav/flight computer. I still spend about 99% of my time in the glider with eyes outside. The only time I look inside is at airspeed in the pattern and when doing navigation things.

When the TRAFFIC came on, I looked inside to find out where, then out and then right back in then out, then in ...... Most of the time was spent trying to locate it on the screens and then figure out where to look out. Absolutely the opposite of what it should have been. When I saw the Cub, it was a lot closer than either one of us liked.

What I am trying now is to look at the map more often and try and keep a mental picture of traffic within a 5 mile radius. When there is traffic that close, I change the screen to about a 3 mile radius (or when in the traffic pattern). When a TRAFFIC call comes on, look outside, avoid looking in to find it on the screen. I find myself spending a more time eyes in than I would have expected.

What technique are others using?

Brantel
08-22-2014, 11:31 AM
What technique are others using?

I put a GoPro in my face once and basically ignored it just to see how my state of the art panel has impacted my eyes outside time. I also mounted one on my head for a similar reason once. Bottom line is that my eyes were outside for 98% of the flight and the one where I had it on my head resulted in a video that would make you sick just to watch due to all the head pivoting.

I think how much a pilot keeps his eyes inside looking at technology varies greatly from pilot to pilot and it is not the technology causing more eyes inside time, it is the pilot. I have seen pilots spend what seems like an eternity with eyes inside trying to decipher a paper sectional so this is not a new problem.

From the get go with my current glass panel I have made it a point to incorporate a glance at the full screen traffic page which I keep scaled for 6 miles and filters out anything greater than +- 2700ft from me similar to the way I learned to scan the instruments during my instrument rating training. Garmin's target trend feature really goes a long way toward keeping your eyes outside and highlighting the targets that are possible threats. This typically keeps the surprises to a minimum. The primary focus is always eyes outside.

There is no such thing as a perfect traffic avoidance system. Eyes, Radar, TCAS, TIS-A, TIS-B, etc. all have their limitations. The important thing is to understand those limitations if you plan to use any of them and if you have access to more than one technology it should greatly reduce your chances of swapping paint with another plane.

Pilots make poor choices just like drivers of cars. Pilots spending too much time eyes inside is no different than the tons of folks that pass me everyday in their car while texting, reading the newspaper or putting on make-up. It is a personal choice and many make that choice with no regard to who they are sharing the road (or the sky) with....

Recap...my personal technique: Know my systems and their capabilities/limitations and keep my primary focus on eyes outside when in VMC.