What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

ADS-B "Save"

GalinHdz

Well Known Member
On Sept 7 I was at 4,00ft IFR on V198 talking to Eglin approach on my way to Milton, FL (2R4) when my SkyView display started giving me a "Traffic Warning". The ADS-B indicated I had traffic 3 miles out, approaching me, head on at my same altitude. When the alert showed the traffic at 1 mile, still approaching me head on and still at my altitude I firmly pulled the nose up and turned to the right. A few seconds later I saw a twin engine airplane about 100ft below me, right where the ADS-B was showing, pass by.

When I got over the "scare" I told the controller what had just happened. The controller sheepishly told me it was a Seneca maneuvering in that area. Needless to say I let the controller know I was a little upset about what happened. When I got on the ground I filled out a NASA form just so my little grain of salt is entered into the system.

I don't know if I would I have seen the traffic without the ADS-B "point out" but being able to know where to look for traffic is a significant safety enhancement. In this case I didn't actually see it until it was extremely close. I am so glad I have this in my airplane.

:cool:
 
Last edited:
Good Reminder

Thanks for sharing Galin. I assume you were on an IFR flight plan, but in VMC. A good reminder for us all to stay alert and keep up our scan even when "in the system".
 
Number to call

Did you give the controller a number to call when you got on the ground? :D

Seriously scary. Really glad it turned out ok!
 
I love having the traffic displayed on the Skyview. It has prevented more than a couple of close calls for me. I'm always amazed at just how many airplanes there are in the SoCal area that you just otherwise wouldn't see. It really reminds you to always keep looking outside.
 
Questions about ADS-B

Okay, so I'll ask the neophyte questions...

Did you receive the traffic alert because the twin had ADS-B out? Or better stated, would you have received an alert if the twin was not equipped with ADS-B out?

I'm just trying to learn. My biggest concern is that out in the boondocks (which is most of the country's airspace), where aircraft without ADS-B out can operate after 2020 legally (generally in non Class A, non Class B and non Class C and Class E below 10,000 MSL), some good ol' boy could come honking along and not be seen by a pilot who's on snooze control because he has the latest and greatest avionics. It's still going to be "see and avoid" for VFR cross-country after 2020, right?

I know I need to read and study about ADS-B, but I'd like to hear some discussion from pilots who are already using it.
 
Last edited:
Thanks for sharing Galin. I assume you were on an IFR flight plan, but in VMC. A good reminder for us all to stay alert and keep up our scan even when "in the system".
Yes I was on an IFR flight plan in very good (No clouds, +10 Vis) VMC conditions. Even so I didn't see the Seneca until the very last second. FWIW: ALL my Landing/Taxi and Strobes/Recognition lights are LED's so, except for the strobes which come on just before takeoff, they are always on from engine start to engine off. Believe me, they are VERY bright.

Did you give the controller a number to call when you got on the ground? :D
After I "firmly informed" the controller of what happened, a different voice came on the radio and told me the Seneca was behind me and no longer a factor. It gave me the impression the original controller, who was quite busy at the time, was a trainee.

Also, you can see my "evasive" maneuver on the FlightAware Track Log from 20:56:21Z to 20:57:03Z. What you can't see there is the effect it had on my underwear. :eek:
 
Last edited:
Honestly if you are talking to someone like Eglin which you have to be in that area, regardless if you are IFR or VFR, if they are talking to you they should have told you about that traffic. I know he/she doesn't have to if you are VFR but they should if they are talking to you. It much worse if you are in IFR and you still weren't told. That's just terrible!!!
 
Okay, so I'll ask the neophyte questions...

Did you receive the traffic alert because the twin had ADS-B out? Or better stated, would you have received an alert if the twin was not equipped with ADS-B out?

I'm just trying to learn. My biggest concern is that out in the boondocks (which is most of the country's airspace), where aircraft without ADS-B out can operate after 2020 legally (in non Class B and non Class C and below 10,000 MSL), some good ol' boy could come honking along and not be seen by a pilot who's on snooze control because he has the latest and greatest avionics. It's still going to be "see and avoid" for VFR cross-country after 2020, right?

I know I need to read and study about ADS-B, but I'd like to hear some discussion from pilots who are already using it.
I don't think the twin had ADS-B OUT since it never displayed a tail number, BUT it could have been in "anonymous" mode. If it didn't have ADS-B OUT but was being "painted" by ATC, it should have shown up anyways. BTW, "see and avoid" will always be the ultimate collision avoidance system while flying.

Honestly if you are talking to someone like Eglin which you have to be in that area, regardless if you are IFR or VFR, if they are talking to you they should have told you about that traffic. I know he/she doesn't have to if you are VFR but they should if they are talking to you. It much worse if you are in IFR and you still weren't told. That's just terrible!!!
I agree 100%, but it goes to emphasis that "see and avoid" is still the best and ultimate collision avoidance system.

:cool:
 
Last edited:
... If it didn't have ADS-B OUT but was being "painted" by ATC, it should have shown up anyways.

What do you mean by "painted?" I take that to mean "on radar." But I don't think there is a link between ATC's radar and the ADS-B system. If so, tell me how, because I haven't found that yet in my study of ADS-B.

This is the main point of my question. If an airplane is not equipped with ADS-B out, the pilot of the ADS-B equipped airplane won't know about it unless he looks out the windshield...and then it's a "maybe."

I believe ADS-B will offer a lot of improvements over what we have now, but I see cracks in the mortar.

It appears to be similar to the situation at our airport (Pryor Regional Airport, Decatur, Alabama, KDCU). It's a rare event, but it is legal to fly a NORDO aircraft into this busy, non-towered, ILS equipped, VOR on-the-field airport that sits under the outer shelf of nearby Huntsville (KHSV) Class C airspace. Those of us with radios (probably 99.9% of aircraft flying into and out of KDCU) make clear, concise radio calls, but our heads are always on swivels prior to taking the active, looking for that NORDO aircraft coming in to land. As good as modern technology is, we must not let it lead us down the road of complacency. I agree with you, "See and avoid" will always be the ultimate collision avoidance system while flying.

P.S. "Good on ya" for remembering to use the NASA Aviation Safety Reporting System.
 
Last edited:
Ground Relay

I believe that ATC ground stations will send up radar target data to ADS-B IN equipped aircraft. Although there may be an interrogation required. Others are better versed in this technology than I.
 
Last edited:
I believe that ATC ground stations will send up radar target data to ADS-B IN equipped aircraft. Although there may be an interrogation required. Others are better versed in this technology than I.

I understood that, too, but I haven't found it yet except in blogs and social media. I've been reading material on ADS-B from FAA, AOPA, Garmin, Appareo, Sporty's and others, and I haven't found yet that radar data is or will be sent to ADS-B in equipped aircraft.

Would someone provide the link? If it's so, it needs to be publicized better, IMO.
 
GalinHdz said:
I don't think the twin had ADS-B OUT since it never displayed a tail number, BUT it could have been in "anonymous" mode. If it didn't have ADS-B OUT but was being "painted" by ATC, it should have shown up anyways. BTW, "see and avoid" will always be the ultimate collision avoidance system while flying.

Very astute observation on your bogey, Galin. ADS-B Anonymous Mode is just that, anonymous. Anonymous doesn't mean "invisible". When a UAT out aircraft elects to use anonymous mode while squawking VFR (only time anonymous works) that aircraft is still completely visible and shown in the system for both ATC and other aircraft. The only difference is that the ICAO code (and N Number) are randomized for privacy reasons. So an ADS-B "in" display will then show "VFR" instead of the N Number and all other critical information is still shown (altitude, speed erc...). Since all you saw was an unidentified target w/o tail number or "VFR" this means that the Seneca probably didn't have ADS-B out but his Mode C was being relayed to your ADS-B "in" reciever by the ground stations.
 
Last edited:
That's the way it's supposed to work. I fly with ADS-B IN and not all traffic shows up.
I've had short flights where I have 3 towers, and no traffic shows up on foreflight. I know it's not my display settings, because on the next flight, I see plenty of traffic on the map.
 
How it's supposed to work

ADS-B in should bring you weather info and traffic info, called TIS-B or traffic information service. Anybody nearby transmitting ADS-B out info on the UAT frequency will show up directly. Any targets the ATC is seeing on their radar or ADS-B stations are picking up should be re-broadcast to you. But, and this is the rub, if you are not broadcasting ADS-B out, you will not trigger the re-broadcast. You have to count on somebody in the same vicinity as you with out capability to trigger the re-broadcast.

Anonymous mode only works with UAT ABS-B out. If you have a Mode S xpdr, you are never, ever anonymous.

Ed Holyoke


That's the way it's supposed to work. I fly with ADS-B IN and not all traffic shows up.
 
What do you mean by "painted?" I take that to mean "on radar." But I don't think there is a link between ATC's radar and the ADS-B system. If so, tell me how, because I haven't found that yet in my study of ADS-B.

I believe the way it works is that Dynon's transponder receives TIS-B "in" which contains up to five nearest radar targets as seen by ground radar and/or their ADS-B "out" caught by ground stations. I don't have ADS-B "in" on my Skyview but still receive nearby traffic targets when near metropolitan areas. Update frequency is several seconds, longer than between ADS-B packets I see on 1090 MHz, and direction of motion indicated tends to waver for targets in straight&level, which would indicate radar pings as the source, perhaps.
 
Here's how it is suppose to work:
1. If you have adsb-out, and -in, and are in contact with an adsb ground station, and
2. There is a nearby aircraft that is known to the system-either it has adsb-out and is talking to an adsb ground station, or it is within atc radar coverage, and if it has ASB-out it is on a different frequency than your adsb-in, then
3. The adsb ground station is suppose to send you that aircraft as traffic.
Radar coverage is not the same as ADSB ground station coverage.

BTW, if you are in VMC collision avoidance with vfr traffic is the pilot's - not ATC's - responsibility. You must keep looking, even if on an ifr flight plan.
 
I have 2 planes at Milton...you really have to keep your head on a swivel. You have Navy/Marine Helos and T6's, Air Force T6's and T1's, Hurlburt and Eglin Traffic, plus all the commercial and flight training just within a 20 NM radius. ADSB is always welcome in this area though you won't necc get the whole picture without ADSB out, or someone nearby with ADSB out. They do train heavily at eglin so I'm sure it was as you described, a trainee and a supervisor. However, there are a **** load of aircraft in the local area without transponders as well who don't talk and won't show up on radar or ADSB. It's very surprising that being IFR they were behind giving you advisories. Stay safe out there
 
I've had short flights where I have 3 towers, and no traffic shows up on foreflight. I know it's not my display settings, because on the next flight, I see plenty of traffic on the map.

Are you equipped with ADS-B Out? If not, you may not receive traffic because you have not been letting the ground stations know you are nearby. On the next flight, a participating ADS-B Out aircraft may have been nearby and triggered the ground stations to transmit data.
 
I understood that, too, but I haven't found it yet except in blogs and social media. I've been reading material on ADS-B from FAA, AOPA, Garmin, Appareo, Sporty's and others, and I haven't found yet that radar data is or will be sent to ADS-B in equipped aircraft.

Would someone provide the link? If it's so, it needs to be publicized better, IMO.
OK, to be more specific:

If ATC is "painting" his non ADS-B transponer response, then you should see him on your ADS-B display. Don't confuse Primary (raw) radar with Secondary (transponder) radar. The caviat is that you must be within ADS-B ground station coverage to see non ADS-B transponer responses.
I have 2 planes at Milton...you really have to keep your head on a swivel. You have Navy/Marine Helos and T6's, Air Force T6's and T1's, Hurlburt and Eglin Traffic, plus all the commercial and flight training just within a 20 NM radius. ADSB is always welcome in this area though you won't necc get the whole picture without ADSB out, or someone nearby with ADSB out. They do train heavily at eglin so I'm sure it was as you described, a trainee and a supervisor. However, there are a **** load of aircraft in the local area without transponders as well who don't talk and won't show up on radar or ADSB. It's very surprising that being IFR they were behind giving you advisories. Stay safe out there

Oh yes. Plus an added benefit of having your head on a swivel in this area is you might get to see some super cool aircraft you otherwise would not see.

:cool:
 
Last edited:
But, and this is the rub, if you are not broadcasting ADS-B out, you will not trigger the re-broadcast. You have to count on somebody in the same vicinity as you with out capability to trigger the re-broadcast.
And the re-broadcast you receive is the traffic meant for the other guy, not necessarily the traffic near you. This can be VERY misleading and give a false sense of security for the person with only ADS-B in.

:cool:
 
Last edited:
Okay, so I'll ask the neophyte questions...

Did you receive the traffic alert because the twin had ADS-B out? Or better stated, would you have received an alert if the twin was not equipped with ADS-B out?

I'm just trying to learn. My biggest concern is that out in the boondocks (which is most of the country's airspace), where aircraft without ADS-B out can operate after 2020 legally (generally in non Class A, non Class B and non Class C and Class E below 10,000 MSL), some good ol' boy could come honking along and not be seen by a pilot who's on snooze control because he has the latest and greatest avionics. It's still going to be "see and avoid" for VFR cross-country after 2020, right?

I know I need to read and study about ADS-B, but I'd like to hear some discussion from pilots who are already using it.

What you are describing is known as ADS-R or "re-broadcast." So theoretically the controller has the twin on his radar, you are ads-b in and out, you should receive the twin's position through ADS-R even though the twin may not have ADS-B out. Here's a brief explanation on the FAA website:

https://www.faa.gov/nextgen/equipadsb/ins_and_outs/
 
What you are describing is known as ADS-R or "re-broadcast." So theoretically the controller has the twin on his radar, you are ads-b in and out, you should receive the twin's position through ADS-R even though the twin may not have ADS-B out. Here's a brief explanation on the FAA website:

https://www.faa.gov/nextgen/equipadsb/ins_and_outs/
Actually it is TIS-B not ADS-R.

"TIS-B is a client-based service that provides ADS-B Out/In equipped aircraft with surveillance information about aircraft that are not ADS-B equipped. To qualify as a TIS-B target, an aircraft must be equipped with a transponder, and be within radar coverage."

;)
 
Last edited:
Yes, you're right, of course. It's TIS-B, not ADS-R, which is a little different. Got to stay on top of all of these acronyms!
 
I feel your pain, if you want to call it that. I am just getting over what should have been a mid air a couple of weeks ago. It gave me the chills all the way home and for a couple of weeks, quite honestly. And it has me wondering if we are paying to much attention to the electronics or just relying on them too much.

I had just performed a DAR inspection at an airport in Florida underneath the Orlando Class B. I was departing and headed north on an IFR flight plan, but had departed without a clearance as it was good VFR where I was departing. After take off at 1000' I did my usual of setting climb power, engaging the autopilot, checking for traffic on the EFIS, & switching frequencies. As I glanced over to the center console to verify the com swap had worked and I was going to be transmitting on the right frequency, something caught my eye flashing by underneath the left wing. It was the top of a Cessna and I really don't know how I missed the ADF antenna wire with my landing gear! Mind you, I had been looking forward up until I glanced over at the radio stack. It was that quick.

A short delay in my takeoff roll, or any other myriad of of things, and I know I would have been a statistic.

I know head on traffic is the hardest to see. We learn it, I teach it as a CFII, and am always watchful. It didn't work this time, and shook me up pretty good.

BTW, I checked the screen and NO traffic showed up on it after we passed, and that person was within 5 seconds of being underneath the Class B. Either the transponder was off, inoperative, or the ADSB hadn't got it to my aircraft yet. I'll never know, but I sure am thankful we didn't collide.

Vic
 
Last edited:
I feel your pain, if you want to call it that. I am just getting over what should have been a mid air a couple of weeks ago. It gave me the chills all the way home and for a couple of weeks, quite honestly. And it has me wondering if we are paying to much attention to the electronics or just relying on them too much.

I had just performed a DAR inspection at an airport in Florida underneath the Orlando Class B. I was departing and headed north on an IFR flight plan, but had departed without a clearance as it was good VFR where I was departing. After take off at 1000' I did my usual of setting climb power, engaging the autopilot, checking for traffic on the EFIS, & switching frequencies. As I glanced over to the center console to verify the com swap had worked and I was going to be transmitting on the right frequency, something caught my eye flashing by underneath the left wing. It was the top of a Cessna and I really don't know how I missed the ADF antenna wire with my landing gear! Mind you, I had been looking forward up until I glanced over at the radio stack. It was that quick.

A short delay in my takeoff roll, or any other myriad of of things, and I know I would have been a statistic.

I know head on traffic is the hardest to see. We learn it, I teach it as a CFII, and am always watchful. It didn't work this time, and shook me up pretty good.

BTW, I checked the screen and NO traffic showed up on it after we passed, and that person was within 5 seconds of being underneath the Class B. Either the transponder was off, inoperative, or the ADSB hadn't got it to my aircraft yet. I'll never know, but I sure am thankful we didn't collide.

Vic

Question: Does Orlando's approach radar support TIS-A, and are you able to receive those targets from your transponder?

I've found that once I'm established on cruise, have the course set, and engaged the autopilot, I spend most of my time looking out of the cockpit in VFR conditions. I occasionally scan the instruments, but now rely more on EFIS alerts than a constant instrument scan. I look at the traffic display from time to time to get an idea what's around, and what might be coming my way. What I find surprising is the traffic that shows up on the display that you never see, and the traffic that you don't see until it gets *too* close. Eye-openning.
 
Wow

... BTW, I checked the screen and NO traffic showed up on it after we passed, and that person was within 5 seconds of being underneath the Class B. Either the transponder was off, inoperative, or the ADSB hadn't got it to my aircraft yet. I'll never know, but I sure am thankful we didn't collide.

Vic
That is scary, Vic. From what I read in this thread, seems like we have to have our heads outside to look for bogeys, keep talking to ATC, make sure we have the latest tech in the cockpit, and be lucky!

I've had a few close calls, but nothing like that. Sure gets your attention.
 
Question: Does Orlando's approach radar support TIS-A, and are you able to receive those targets from your transponder?


Yes, I see TIS-A targets in the Atlanta area (it even says TIS-A on the AFS EFIS). I don't know if Orlando supports TIS-A.

I agree with the other comment about how many targets are displayed and yet it seems like sometimes no amount of eyestraining and looking can visually acquire the target. Spooky at times.

What I really hate is to be in solid IMC and hear ATC call a traffic followed by "we aren't talking to him." Have had that happen more than once. Yes, there's no doubt they are IFR without a clearance.

Vic
 
Are you equipped with ADS-B Out? If not, you may not receive traffic because you have not been letting the ground stations know you are nearby. On the next flight, a participating ADS-B Out aircraft may have been nearby and triggered the ground stations to transmit data.

Thanks for the explanation - it makes sense. I don't have ADS-B out yet. I was flying out of KFDK and there were multiple aircraft around, including an incoming medivac chopper. I assume those guys have out.
 
What I really hate is to be in solid IMC and hear ATC call a traffic followed by "we aren't talking to him." Have had that happen more than once. Yes, there's no doubt they are IFR without a clearance.
That is the one thing that scares me most while flying. But like you it has happened to me more than once. :mad:
 
ADS-B alert on last flight

On my last flight I was VFR 10 NM out from departure from KFNT (Flint MI) level at 2500. The Archer I was flying just had ADS-B in/out installed about 3 months ago. I was looking out the window, mostly forward and had an audio alert at my 2 o'clock, same altitude. I saw the aircraft almost instantly converging at near right angles and pulled back.

In the few seconds it took to pull back and climb the aircraft passed about 100 ft underneath. It would have been very close, if not a collision. The other aircraft never altered course. Those few seconds of warning may well have saved the day. I don't think I would have seen the traffic in time to do anything without the audio alert.
I don't recall if I was receiving flight following as I almost always do, but certainly did not get a call from the controller. I also didn't see the traffic displayed on the (very small) GPS screen. (All steam gauges except the GPS.)

Like everyone else, I have searched over and over for displayed targets and not been able to seen them. I always wondered what form a traffic alert would take, and how close the traffic needed to be. Now I know.

On another interesting ADS-B note;

On the way home from Oshkosh I was flying north up the Green Bay peninsula in a 182 RG with ADS-B in/out switching from nearby CTAF to CTAF when I was asked if my call sign was on frequency. I answered somewhat surprised at the call on a frequency I only just switched to. Another aircraft with ADS-B in/out saw I was overtaking and asked by N number, if I wanted some air to air shots. I couldn't turn that down, so when we overtook, we slowed and flew some loose formation, geting some nice shots of each other.
Sadly, I gave him my email to send the photos and have never received them. His N number goes to a LLC address with no contact success so far.
 
ADSB Fails

Thought I would add two examples of recent fails. I have the Dynon ADSB with the 2020 GPS and did an FAA check on the two episodes. These checks show the unit was functioning properly.

1. 20 miles southeast of Austin,TX Class C at 6500, just outside the horizontal limits of an additional class D space, flying southwest in the evening with quite a bit of haze, a Bonanza at same altitude and heading came into few that I was overtaking. (Cool, huh). He was never on my ADSB, despite other targets on the screen throughout the 40 minute trip from KCLL to KBAZ. Once I saw him, I kept him in view and he never showed up. This was 2 days ago.

2. Sept 4 this year. Just outside DFW Class B at 10500 on the Northwest side. What looked like a Viking was seen 500-1000 Ft below coming from my 10:00 from the Dallas area. Crossed underneath me and never showed up on the ADSB. I was on a long cross country and had plenty other TIS and non-TIS targets that did show up.

I've decided it may be good for missile range to get an idea of what's coming, but no faith in it at gun range.
 
You might check your adsb-out settings. If you're transmitting that you can receive both adsb frequencies, then the ground stations will not send up info for any targets with adsb-out. If in fact your -in box is single frequency, then you'll miss some traffic.
 
adsb fail

thank you.
I checked and do not see anything on skyview that allows me to select frequency. Maybe if I had a non-skyview adsb receiver attached, it would allow me to select frequencies.
 
Last edited:
thank you.
I checked and do not see anything on skyview that allows me to select frequency. Maybe if I had a non-skyview adsb receiver attached, it would allow me to select frequencies.

The setting is in the serial port setup section. Dynon has two different ADS-B receivers: SV-ADSB-470 is the 978 version, SV-ADSB-472 is the dual band version (978 & 1090.) The Dynon install manual v.AB, pg 14-2 tells all.

My home airport is Easton (ESN,) which is just on the fringe of radar coverage from BWI, and just outside coverage from NAS Pax River and Dover AFB. On a good day, BWI radar can see planes in the vicinity, thus I receive TIS-A target data. However, on a "bad" day, BWI radar doesn't cover us. A few days ago I was doing some local work and I noticed that a twin I could clearly see on the downwind was not displaying on my traffic screen, while an aircraft on the ground was displayed. A few minutes later, I was departing the area northwest towards BWI and all of a sudden a (TIS-A) target appeared in front of me about 1 nm and a few hundred feet above. These encounters illustrate that there are "holes" in the current traffic solutions, particularly when the "bogie" is not equipped with ADS-B Out, and is flying outside of a radar service area.
 
You might check your adsb-out settings. If you're transmitting that you can receive both adsb frequencies, then the ground stations will not send up info for any targets with adsb-out. If in fact your -in box is single frequency, then you'll miss some traffic.

Very interesting. So what is the most productive in frequency setting for an aircraft with UAT "out" yet also having a dual-frequency "in" portable (i.e. Scout, GDL 39, Stratux, Dual, iLevel)?

I have been under the impression that if the aircraft ADS-B transmiter is set up with the message that it has only a 978Mhz or a 1090Mhz receiver that the system would not transmit the other missing frequency information. Whereas if the aicraft tells the system it has both frequencies "in" it will see all information.

But now Bob Turner's explanation, which is opposite of my original impressions, kind of makes sense. Thankfully single-band recievers are becoming very rare.

This is turning into a very educational thread albeit straying slightly from the initial near miss topic.

Thanks,

Jim
 
I'm running a Stratus Appareo ESG transponder for ADSB-out, Ifly740 w/ ping buddy for ADSB-in. I've seen "out of ground station range" messages, but can't recall a corresponding "within" or "back in" range message. Am I supposed to be able to see them on the moving map or how does one definitively know when in range of a ground station?

Doug
Seattle area
 
I'm running a Stratus Appareo ESG transponder for ADSB-out, Ifly740 w/ ping buddy for ADSB-in. I've seen "out of ground station range" messages, but can't recall a corresponding "within" or "back in" range message. Am I supposed to be able to see them on the moving map or how does one definitively know when in range of a ground station?

Doug
Seattle area

Depends on the display. I hav a Skyradar for adsb-in. On the GRT HX, the number of ground stations within range is shown on the bottom right of the map page. For the iPad/WingX, it's shown bottom middle just below the moving map.
 
Any targets the ATC is seeing on their radar or ADS-B stations are picking up should be re-broadcast to you.
Ed Holyoke

TIS-b only relays targets with altitude (Mode C or ADS-b). It does not send targets for transponder equipped aircraft that are not providing Mode C data or non-transponder aircraft (primary only targets). ATC sees more on their radar than they are sending you in many cases.

Larry
 
Back
Top