ADS-B Traffic Lag

SixPapaCharlie

SixPapaCharlie

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The last 2 flights I made, I notice the traffic I was seeing was delayed about 3-5 minutes behind reality.
I watched a plane do 2 laps around the pattern and depart to the south. I took off and the plane was gone. Foreflight showed it doing the 2 laps and departing.

As I got near a Class D, I listened to the tower clearing people to land that my iPad was showing 10 miles out. I could describe 10 more examples but the traffic on the iPad was lagging significantly.

I am using Foreflight on an iPad mini 4, talking to a Stratus transponder in my plane.
What might cause the delay?
 
SixPapaCharlie said:
The last 2 flights I made, I notice the traffic I was seeing was delayed about 3-5 minutes behind reality.
I watched a plane do 2 laps around the pattern and depart to the south. I took off and the plane was gone. Foreflight showed it doing the 2 laps and departing.

As I got near a Class D, I listened to the tower clearing people to land that my iPad was showing 10 miles out. I could describe 10 more examples but the traffic on the iPad was lagging significantly.

I am using Foreflight on an iPad mini 4, talking to a Stratus transponder in my plane.
What might cause the delay?
Click to expand...
Any / every one of the potentially many hops from the transmitting plane to the receiving plane.
 
Are you sure while on the ground that your iPad was connected to the Stratus and not Internet? Internet traffic is delayed.

Interesting that what you perceived as traffic you perceived as "10 miles" out talking to tower had landing clearances. Was tower not busy? I've gotten landing clearances from a distance away from the airport.

Any ADS-B traffic received from FAA Ground Towers will have some minor processing delay.

The iPad mini 4 is an older processor and will slow down with heat issues or too many apps open at once.
 
BillTIZ said:
Are you sure while on the ground that your iPad was connected to the Stratus and not Internet? Internet traffic is delayed.

Interesting that what you perceived as traffic you perceived as "10 miles" out talking to tower had landing clearances. Was tower not busy? I've gotten landing clearances from a distance away from the airport.

Any ADS-B traffic received from FAA Ground Towers will have some minor processing delay.

The iPad mini 4 is an older processor and will slow down with heat issues or too many apps open at once.
Click to expand...
I was airborne.
No it was clearly delayed. the cleared to land traffic and I departed the pattern at similar times.
Tower was slammed. It was KDTO they are always slammed lately. The only reason I was listening to the tower is because there was a high volume of planes in the area (On my ipad) It really was delayed. When he reported "Over Krum" to tower, he was miles from it.

I watched a plane pass me off my left side and about 3 minutes later the iPad showed it where I was when I had eyes on it.
It really was showing all the traffic delayed. Worth mentioning on both of these recent flights, there were moments where towers were reported as marginal, then no towers, then back to normal but delayed.
 
Mine has shown delays before, but nowhere near that bad. It has also alerted me to an aircraft at same altitude right behind me. It was merely reporting me a few seconds ago.
 
BillTIZ said:
Are you sure while on the ground that your iPad was connected to the Stratus and not Internet? Internet traffic is delayed.
Click to expand...
That's exactly what I was thinking. Is your iPad cellular capable?
Perhaps it was getting traffic from the internet feed and not the Stratus. You'd have needed to see if Foreflight was indeed connected to the Stratus at the time you saw the descrepency.
 
Mine doesn't have cellular, and I know a lot of times I'm looking out the window for a plane that's showing up on the iPad, and never see 'em.

Wondering if it's possible the ADS-B out units are also a factor, in regards to their transmission continuity.
 
I've gotten the alerts from my own ADS-B shadow which scares the poop out of me every time. "Traffic, 6 o'clock, 0 miles" :eek2:

I wonder if it was just a delay from the ADS-B broadcast due to high traffic in the area and that caused the Stratus to get confused.
 
baboss said:
That's exactly what I was thinking. Is your iPad cellular capable?
Perhaps it was getting traffic from the internet feed and not the Stratus. You'd have needed to see if Foreflight was indeed connected to the Stratus at the time you saw the discrepancy.
Click to expand...
As an experiment, turn off your cellular data next time.
 
mark.staggs said:
I've gotten the alerts from my own ADS-B shadow which scares the poop out of me every time. "Traffic, 6 o'clock, 0 miles" :eek2:
Click to expand...
That’s pretty much what mine said. Almost started my aerobatic training right then.
 
ADS-B transmits from plane to plane for those properly equipped. If a plane is equipped with a transponder but without ADS-B out the traffic would be delayed. If you are in non-towered airspace or Class D ADS-B is not required (unless it is in a veil or over class C).

Edited for correction (see below)
 
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I've also noticed delays in ADSB traffic from time to time, but never anything that bad. More like 20 seconds at the most.
 
Mine doesn't have cellular capability. Today I took a test flight and I went up and it showed me all of the traffic but it was all just frozen none of it ever moved
 
Just confirming you wrote iPad mini 4th gen, released in 2015, and you are wondering about performance issues, in 2024…. I mean it doesn’t take a door plug falling off the plane to narrow this issue down.
 
I was at the airport yesterday watching planes and using ForeFlight with my iPhone’s cellular connection. Delay was about 15 seconds. It is the most recent iPhone and version of ForeFlight.
 
masloki said:
Just confirming you wrote iPad mini 4th gen, released in 2015, and you are wondering about performance issues, in 2024…. I mean it doesn’t take a door plug falling off the plane to narrow this issue down.
Click to expand...
It is but it hasn't had any issues up until just suddenly
 
I think it's a four. Let me double check there's no way I got it in 2015
 
Okay just confirmed it's an iPad mini 4. If it's that old I guess I'll get a newer model. What's the best iPad mini to get right now is it the six?
 
SixPapaCharlie said:
Okay just confirmed it's an iPad mini 4. If it's that old I guess I'll get a newer model. What's the best iPad mini to get right now is it the six?
Click to expand...
Wait for the next mini, or buy the current gen iPad Air today. They don't update the mini often which means it will be behind in security updates, etc. The Air isn't that much bigger nor that much more expensive; it was worth it to me when I retired the 2019 Air to beer brewing duties. I may also have dropped it and the screen crack was a little tiresome while flying.
Edit to add: also dedicate the current mini to flying. Do a full hardware reset and restore and only install Foreflight. That should buy you time unless Foreflight did something silly in their app stack. In which case, more horsepower solves most silly coding issues.
 
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Okay I'll look at the air. I have to buy something today. Mines scaring me a little with the incorrect traffic issue. Traffic will just show up a mile in front of me at the same altitude and I can't see it for the life of me because it's not really there but it was a few minutes before
 
SixPapaCharlie said:
Okay I'll look at the air. I have to buy something today. Mines scaring me a little with the incorrect traffic issue. Traffic will just show up a mile in front of me at the same altitude and I can't see it for the life of me because it's not really there but it was a few minutes before
Click to expand...
Costco.
 
Before you spend money on a new iPad, see if you have the same issue with another Stratus unit, or a Stratux or Sentry.
 
Do you also see this lag with FFlight on your I Phone?
 
20 sec delay is to be expected with the 978 rebroadcast. With the 1090, the air-to-air portion, should be faster.
 
Yeah, I think you should do some more troubleshooting before you replace the iPad. I'm not convinced it's the iPad... Have you checked with ForeFlight to see if the iPad mini 4 is supported?
 
Daleandee said:
ADS-B transmits from plane to plane for those properly equipped. If a plane is equipped with a transponder but without ADS-B out the traffic would be delayed. If you are in non-towered airspace or Class D ADS-B is not required (unless it is in a veil or under class C shelf, etc).
Click to expand...
You need ADSB above class C, but not below.
 
WDD said:
Do you also see this lag with FFlight on your I Phone?
Click to expand...
I am an android user. I only have an ipad because foreflight doesnt have an android version.
 
MacFlier said:
Before you spend money on a new iPad, see if you have the same issue with another Stratus unit, or a Stratux or Sentry.
Click to expand...
I have another Stratus. I will see if I see any difference before I purchase an ipad.
 
FPK1 said:
Yeah, I think you should do some more troubleshooting before you replace the iPad. I'm not convinced it's the iPad... Have you checked with ForeFlight to see if the iPad mini 4 is supported?
Click to expand...
I think it is ommitted from their preferred models now. I went to foreflight's site and this is all I see

ipad2.pngipad.png
 
Fore flight has a lot more bloat and does many more things than it used to. May be time to upgrade your iPad.
 
WalterH said:
You need ADSB above class C, but not below.
Click to expand...

I wrote that thinking I meant the class D or Class C was inside a veil. Thanks for the catch. I did make an edit ...
 
IIRC, ForeFlight won't show internet traffic if you're moving.

If your iPad is a non-cellular model, presumably ForeFlight is using the Stratus as its position source, which is fine and good. Was there any GPS interference testing going on in your area?
 
From time to time, I have seen reports of delayed ADS-B traffic positions. They were all with a Stratus. Not only was other traffic delayed, ownship was also delayed. This caused the ownship suppression to fail when the ownship delay was far enough behind one's current position. I termed it the behind me syndrome, meaning that ownship would drift further and further behind its actual position. This is different than the pop up ghost that is a few seconds behind the true position, but rather an extended position delay, sometimes in terms of minutes. I haven't seen such a report in the last many years. Normal ADS-B should be up to date within seconds of real time. Those that are not ADS-B Out equipped that end up causing a TIS-B can be up to 12 seconds delayed, but TIS-B should be rarer now a days as 80% of the fleet is ADS-B Out equipped, so the ground station does not figure into the equation as often.
 
What version of Stratus do you have? If it is a 3i then try this. Get a free 30 day trial of IFly and load it on your Android phone. If you see traffic lag improved then problem probably is with FFlight and your old I Pad. Either get a new I pad or do what I do - use FFlight on the ground but IFly in the air (because it’s a lot simpler and more robust in the the cockpit)

If your Stratus version is older than 3i, then never mind. (I Fly uses the open ADSB protocol, and pre 3i Stratus versions used the closed ForeFlight protocol).
 
WDD said:
use FFlight on the ground but IFly in the air (because it’s a lot simpler and more robust in the the cockpit)
Click to expand...
:yeahthat:

Except I dropped FF a couple of years ago when they raised the price and added features I didn't need and that wouldn't run on my old iPad anyway. I do like FF better for planning, but iFly is good enough and it's better in the cockpit.
 
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WDD said:
What version of Stratus do you have? If it is a 3i then try this. Get a free 30 day trial of IFly and load it on your Android phone. If you see traffic lag improved then problem probably is with FFlight and your old I Pad. Either get a new I pad or do what I do - use FFlight on the ground but IFly in the air (because it’s a lot simpler and more robust in the the cockpit)

If your Stratus version is older than 3i, then never mind. (I Fly uses the open ADSB protocol, and pre 3i Stratus versions used the closed ForeFlight protocol).
Click to expand...
Mine is the stratus transponder so I don't know what version of Stratus that is.
I do have a portable one as well I will test that one and see if it has the same issue
 
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