ADS-B in saved my bacon

Jim,

First, this was not a ghost, based on the screen shots provided. The two aircraft that are showing an N number are most likely ADS-B equipped and if they are obtaining client status, any target within 3500 feet altitude and 15 NM will show as a TISB target. This suggests that you are within the TISB hockey puck of N9423N. Both your aircraft and the other fellow are within the TISB area of N9423N. Your TISB target would have been detected by ForeFlight and after a few seconds should have disappeared, once ForeFlight recognized it as your ownship. The other target 300 feet below you is too far away to be your shadow. Also, the shadow will be going the same direction as you are, so when you show the second screenshot, you are going in opposite directions. A TISB target generally does not have an N number associated with it.

You probably lost the other target when both of you exited outside of the equipped aircraft's hockey puck. If you get ADS-B Out, you will carry your own hockey puck around with you and not be dependent on a transitory situation that does not last long. As it stands today, without ADS-B Out, you will only see a few percent of the traffic that represents a threat to you, you were lucky and should invest in a lottery ticket. If you get ADS-B Out, it will enable you to point out 95% of the traffic, but you have to keep your eyes out.

In Petrolero's case, the other aircraft was almost definitely another aircraft because it was displaying an N number which makes it most likely an ADS-B Out equipped target. Even if it was a TISB target with an N number, the N number did not match Petrolero's, so it was real IMHO.
 
Brad Z said:
A shadow of you!

Like I mentioned in my last post, your ADS-B in device picks up not just other ADS-B out equipped aircraft, but traffic information from the ADS-B ground station. The ground station transmits all known traffic information (TIS-B), regardless of the source.
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Brad,

ADS-B ground stations do not broadcast all known traffic. It only broadcasts traffic relative to clients that are ADS-B equipped and configured to solicit the TISB service. For TISB, only the traffic relative to the client's position within a 15 NM radius and +/- 3500 foot of altitude of a client aircraft configured to receive the service will be generated by the ground station. Only targets with mode A/C or S with an altitude will be included, those without altitude or a transponder will not be included.

An ADS-B equipped aircraft does not need or want a TISB to be generated for ownship, after all, it knows where it is and is broadcasting its position for the ground station and others to receive. Undoubtedly it will also have a transponder on board and be detected by secondary radar. The ground station is supposed to reconcile the radar return with the ADS-B position and suppress the own ship TISB from the radar return. Occasionally, particularly when a long range enroute radar is the only source for the transponder return, the position will have sufficient inaccuracy that the ground station can't reconcile the two as the same target, in which case it erroneously transmits a ghost TISB. There are other causes, but this is a typical one. I have seen ghosts with my certified equipment maybe 4 or 5 times in the two years I have had it installed. It seems that they tend to occur in the same places. Normally a target is seen quite some distance away and slowly comes closer. A ghost appears without prior warning and does wake you up, but it happens infrequently enough that I value the added utility of helping me locate traffic.
 
I'm gonna need a subscription to NHL Center Ice, to keep up with all these hockey pucks. :)

Jesus saves, Gretsky shoots and SCORES!!!!
 
Kiddo's Driver said:
It is safe to assume that if he had ADS-B out he probably had ADS-B in
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Actually I don't think that's a safe assumption at all. Local FBO has one rental plane with ADS-B out and nobody but the owner has a Stratus. It costs money to add ADS-B in to the panel and I don't expect everyone to be paying for it.
 
Kiddo's Driver said:
Also, part of the reason I was so far turned back towards him was that it took both hands to do the screen shot on the iPad. I think I bumped the yoke while doing it.
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Be careful out there, boys and girls. Fly your airplane first, play with gadgets later.
 
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