Logic of GTX 345 traffic call out

WannFly

WannFly

Final Approach
Joined
Nov 28, 2016
Messages
6,553
Location
KLZU
Display Name
Display name:
Priyo
Anyone knows what logic garmin uses for traffic call out with GTX 345? I have never heard the call out which is probably a good thing or bad. I get audio out of 345, just no traffic call out. Closest I have been that I can see on the MFD is less than 2 miles and 1200 feet below, obviously not an immediate factor, but would like to know the parameters.
 
I usually get a ForeFlight traffic alert long before my gtx sends me one. I don’t know the numbers though. I guess I have never paid attention.


Sent from my iPhone using Tapatalk Pro
 
I've had 1 call out and I believe we were same alt and a mile apart. I had visual on him way before I got the call out.
 
I'm sure I've never gotten a call at more than two miles, and I think that unless it's going to pass within 1/2 mile of you it still won't.

Put it this way - When it warns you, you'd best pay attention, and you probably won't have trouble seeing the traffic.

I think Garmin overall does a pretty good job of not crying wolf. The terrain alerts also don't come up unless a collision is imminent.
 
I find it surprisingly difficult to decide the best path to avoid the traffic using the 530 or the 750 depictions (although this issue is likely nothing to do with either Garmin or any traffic device. It could be me.)

Usually it is near an airport with both me and the opposing traffic maneuvering vertically and turning - it takes a few seconds to figure out where the other guy is, and where he is going.
And I have seen several times where traffic is shown at 45° to your straight-line path but there it is out the window almost at 90°, passing your wingtip.

I basically use it now to reinforce the need to have eyes out.

About the Foreflight traffic audio alerts. Is there a way to BT that into a headset? (A20 with BT of course) Or even via cable.
 
Let'sgoflying! said:
I find it surprisingly difficult to decide the best path to avoid the traffic using the 530 or the 750 depictions (although this issue is likely nothing to do with either Garmin or any traffic device. It could be me.)
Click to expand...

Do you have TargetTrend on on the 750? If you do, there will be a green line extending from each target indicating their direction and rate of travel *relative to yours*. It's a big help in figuring out the future traffic picture.

About the Foreflight traffic audio alerts. Is there a way to BT that into a headset? (A20 with BT of course) Or even via cable.
Click to expand...

Sure, just bluetooth to the headset as if you were playing music, and all of the ForeFlight audio alerts will go there too. Just make sure that your headset has its "auto-mute" function turned off, otherwise an ATC call for someone else may suppress the ForeFlight alert.
 
Yes Kent I have the leading line off the target. Sometimes it is moving which adds to the difficulty!

From the Pilot Manual 3X5:
(which might be the most detail we are allowed to know about the logic)
4.1 Traffic Alerting
To enhance situational awareness, the GTX 345 provides traffic alerting for ADS-B, ADSR,
and TIS-B targets. An aural message issues when an alert becomes active.
For example, “Traffic! Two O’clock, Low, Two Miles.”
Alerting parameters provide enough time after an alert is generated to acquire the target
and maneuver the aircraft away from the conflicting traffic. The alerting parameters
consider:
1. Closure rate of each aircraft (ownship and target)
2. Altitude separation and trend
3. Speed
4. Angle
 
One of the few times I remember getting a traffic call from the 345 was when I passed 500 above someone. FF is much more likely to give a traffic call than the 345. FF also gives out way too many terrain alerts.
 
Let'sgoflying! said:
Yes Kent I have the leading line off the target. Sometimes it is moving which adds to the difficulty!
Click to expand...

Are your lines white or green?

Also, if they're moving in anything other than a straight line, either you or the other aircraft is maneuvering.
 
Guess you have to think if it calls traffic 2 plus miles away, in a busy area it would never shut up!
 
Sounds like we need to meet up and social distance at about 1 mile to test your 345.

My latest callouts from “Betty” we’re departing a FCM parallel. About 200gl the 345 called out traffic about 700agl ahead of me on the other parallel. Made sense. But it did the call out again which I thought was weird.

I’ve also received it on short final for a plane taxiing back.

It would seem you typically need to be within 500ft vertically and within a mile. I think I have received a traffic call out beyond 1 mile but it was more head on. It’s definitely not overdoing it.

To bad for covid crap...all you’d have to do is one approach into Grand Forks and Betty will start bitchin’ :)
 
@Sinistar lets do it once i get her back. yah i was kinda sad to fly over grand forks and see ONE plane in the pattern and the entire time i was with the approach it was dead quite to a point where i had to call up and ask if they were still there :eek:
 
I believe the certified equipment has a much more sophisticated algorithm to generate an alert for traffic than the portable systems which are primarily based on distance. The certified systems seem to be more based on time to crossing of the dynamic paths of both the target and ownship. They take into account velocity, turning, climb/descent rates of both target and ownship. I have seen alerts that have called traffic 5 miles, rapid climbing, high speed traffic. An alert based solely on distance of a mile or so, it would have been too late to locate the target visually and take any useful evasive action. I rely on the certified equipment for traffic.
 
simtech said:
Guess you have to think if it calls traffic 2 plus miles away, in a busy area it would never shut up!
Click to expand...

Not to mention, it's hard to see traffic much farther away than that. No sense pointing it out if you won't be able to see it anyway.
 
You must log in or register to reply here.
Back
Top