Disappearing Traffic on TCAS

Guest Discussion
1

I have a 2015 22/T. I have always noted nearby traffic disappear from the display and “maybe” reappear OR traffic that wasn’t there suddenly appear in near proximity to the aircraft. This does not happen all the time or with all targets. I have had three other models of aircraft and this has not been the case.

I have squawked this to the SC a couple of times and they report… no issue found

I have even videoed an occurrence of it.

Anyone else seen this. Anyone seen this and had it resolved???

Thanks

2

What kind of traffic system? Is it ADS-B or active traffic?

3

the standard on 2015’s… For that year, ADS-B… and I understand that all ac’s are not ADS-B equipped.

4

Rick,

Hard to tell without knowing which box you have…

Have you checked your settings?

If I remember correctly, in our plane I could set traffic detection for:

-ABOVE

-NORMAL

-BELOW

-UNRESTRICTED

5

I think this is fairly normal, at least it is in my plane, as even with two antennae in my system there are still dead spots where the TCAS loses the traffic. Remember what the system is for-to alert you to look outside for traffic and hopefully give you a sense of where to look. If it picks up a good signal and then it goes away, pretty sure that plane is still there. Just look for it.

6

I have seen that sort of stuff with ADS-B traffic. I do not see that with active traffic. I don’t have any explanation other than the data comes from the Feds and since it is their systems generating the reply I sort of see it as a feature. AKA, a data glitch. It is one reason I consider my active traffic system primary.

I think ADS-B traffic has gotten significantly better since I first got it. But it still has a ways to go. IMO.

7

It does get confusing too for those of us who have ADS-B in (Stratus and ForeFlight in my case), but don’t have ADS-B OUT yet. I can see traffic that has ADS-B out. But may or may not see traffic with standard transponder. It depends on the “Pucks”. ATC draws a virtual “puck” of 3500 vertical feet and 30nm diameter of airspace around every ADS-B OUT equipped airplane. If there is a non-ADS B out airplane that is squawking on a transponder within that “puck”, ATC will rebroadcast the location of that airplane on ADS-B. So I may see other airplanes in ADS-B in, but I may not. Still need head on a swivel and eyes outside!

8

Jim,

Yes, it is confusing. But the OP and myself do have ADS-B out so we should be getting valid data.

Absolutely true about the swivel, regardless of the traffic system.

9

I’ll check

10

But to be clear, I understand about blind spots but I’m talking about close proximity… sometimes within 2 or 3 miles and within 500 feet of altitude. There then gone, or not there at all (and called out be ATC) and then there.

All the time seeing 10 and 12 mile targets ± 3K in altitude

I see if I can find the video I shot of the MDF one time when this happened

11

Love to see the video. I never said, and do not think, that you have blindspots. I think it is more likely you have ADS-B transmit issues. Not reception.

12

That seems to be where I notice the kind spots the most on my active system. Usually crossing below me.

13

Blind. Not kind. Even though they rhyme.

14

I agree, ADS-B In traffic can be “hit or miss”, pardon the pun. I believe this tends to occur when we silently switch from ground based TIS-B feed, to limited or no ground information, where the only ADS-B traffic you see is someone else who has ADS-B Out. On a 430W, you can determine whether you are receiving TIS-B by looking at the traffic display and seeing “ADS INC”; on ForeFlight, you need to view the number of “towers” you are seeing, although I don’t recall where that shows up. You can also surmise no TIS-B services if your NEXRAD imagery is more than 10 minutes old.

Skywatch actually does a pretty good job of seeing traffic, including traffic under you, at least at some distance; I’ve found once a target is close and beneath you, it disappears as well.

Once more people equip with Out, and everyone using In has dual band receivers, I suspect the active and passive systems will be similar in the traffic they report.

15

I don’t get any blind spots AFAIK with the NGT9000 either for active or ADSB traffic. But there is no TIS-B here so that may make a difference.

via COPAme
Samsung SM-T820

16

The other day flying to MI my stratus was showing traffic -003 under me same direction of flight. This happened for the remaining 30 min of my flight. Even when I descended into the airport. Didn’t happen on the way home. Who knows. Did pique my interest until I determined it was a false reading.

17

Sounds like ghosting. The Feds were telling you about you. Next time it happens, if you have a display that supports it look at the tail number. For example on my iPad with ForeFlight I can press the target and it will give information about it. My Aspens allow me to display flight ID a different way. I don’t know what all systems (including Perspective) but there is often a way. You will see tail number if its broadcast, speed, etc…).