GPS suspend/unsuspend

ahmad

ahmad

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To be or not to be. That's the question.

Trying to understand this suspend and unsuspend thing on the garmin after going missed.

I find myself clueless on this when the garmin gives me this pop up.

Can someone clarify this please?
What does it mean and when do I want to be or not to be suspended.
 
"Suspend" is referring to the sequencing of the GPS, if you unsuspend it will activate the published missed procedure in the GPS. If you remain suspended it will basically do nothing.
 
I'll assume you're talking about the 430/530 (W and non-W) series here.

As you fly an approach, the GPS will auto-sequence to the next waypoint as you pass each one. That's normal and desired. But (generally) these units only have the ability to take you directly there. So, on a missed approach it may have "climb to 1800 then right turn direct XXXXX". Unfortunately, those GPS units do not have the "1800" in their programming. So if it went direct to the next waypoint after the MAP, it might not be complying with the procedure (and might fly you into a mountain, or tower or something).

So they have the "SUSP" annunciation come up when you cross the MAP. Then it's up to you to decide when to unsuspend it. Maybe you're landing and don't care. Maybe the missed approach is straight ahead so you can go to that next waypoint right away. Or maybe it's a "climb to 1800 then..." type of missed where you need to wait until you've climbed straight ahead to that altitude before going to the next waypoint.

And you accomplish that by pressing the button labeled OBS, which tells the GPS that you're ready for guidance to the next waypoint.

That's the basic version. Maybe not 100% accurate in terminology but that's the idea.

There is another common situation where "SUSP" shows up but we hardly ever notice it (though it happens a lot). Typically the GPS will be providing guidance to the nearest waypoint in you flight plan. But this is not always the case. Like if you activate vectors to final, and you are closer to the MAP than the FAF (as you get vectored on a downwind, you will be), you don't want it providing you guidance to the MAP yet. So it will go into SUSP mode automatically. Once you get past the FAF outbound, and therefore the FAF is the closest waypoint, it will automatically go away.

We don't notice that one as much because we're not looking for it. But I've seen some people notice it, and try to "fix" it by pressing the OBS button. Well, this ends up messing things up and they typically just have to re-load the procedure.
 
Hey RussR, I have a question for you on the GTN series. I get the option to remain suspended or unsuspend. If a climb is required before going to the next waypoint, I don't push either button until I'm at the required altitude. Just curious, If I hit remain suspended and climb to the proper altitude and want to restart the sequencing, what's the best way to do that? I've never pushed the remain suspended unless I'm on the ground. Thanks!
 
AlphaMike said:
Hey RussR, I have a question for you on the GTN series. I get the option to remain suspended or unsuspend. If a climb is required before going to the next waypoint, I don't push either button until I'm at the required altitude. Just curious, If I hit remain suspended and climb to the proper altitude and want to restart the sequencing, what's the best way to do that? I've never pushed the remain suspended unless I'm on the ground. Thanks!
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It's been a while, but I believe the GTNs have the turn altitude encoded into the procedure. So you should just be able to press "unsuspend" as soon as you go missed.
 
Thank you all for the responses. I understand it now.
 
Now - why could they not make it simply "Activate Missed - Yes or No"
 
WDD said:
Now - why could they not make it simply "Activate Missed - Yes or No"
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That's pretty much what it is on the GTN series and newer. The "SUSP" is only on the 430/530 series, which were originally designed in the late 90's!
 
RussR said:
WDD said:
Now - why could they not make it simply "Activate Missed - Yes or No"
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That's pretty much what it is on the GTN series and newer.
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Sort of. It's a bit more verbose than that. And apparently the order is "no or yes".
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On the GTN, Suspend also comes into play on a hold that is part of an approach. If you need to stay in the hold, you need to suspend to avoid going down the approach after the first turn. Think of SUSPEND as suspending sequencing vs "deactivating" the GPS guidance and then it gets a bit easier mentally (at least for me)
 
WDD said:
Now - why could they not make it simply "Activate Missed - Yes or No"
Click to expand...
they could have. But I suspect consistency in nomenclature in what was originally a less visual system. Although it also allows manual GPS course selection, that OBS button's universal function is to suspend and unsuspend automatic sequencing of waypoints. They probably could have labeled it SUS rather than OBS.

Just a choice among others. Just one of the simpler things we have to learn about the equipment we fly.
 
Hang 4 said:
Think of SUSPEND as suspending sequencing vs "deactivating" the GPS guidance and then it gets a bit easier mentally (at least for me)
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That's exactly the way to think about it because that's exactly what it does in every phase of flight.
 
midlifeflyer said:
they could have. But I suspect consistency in nomenclature in what was originally a less visual system. Although it also allows manual GPS course selection, that OBS button's universal function is to suspend and unsuspend automatic sequencing of waypoints. They probably could have labeled it SUS rather than OBS.

Just a choice among others. Just one of the simpler things we have to learn about the equipment we fly.
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I get what you’re saying. But I would say that OBS allowing manual Course Selection is its function. Using it to ‘suspend’ sequencing is a useful tool. It allowed not having one more button. Labeling the one there is SUS, would then mean you’d be pushing SUS when what you wanted to do was simply just use OBS mode.
 
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luvflyin said:
I get what you’re saying. But I would say that OBS allowing manual Course Selection is its function. Using it to ‘suspend’ sequencing is a useful tool. It allowed not having one more button. Labeling the one there is SUS, would then mean you’d be pushing SUS when what you wanted to do was simply just use OBS mode.
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We all ultimately find our own ways to make it click, but I never really understood the button until I began to think of it as the suspend button. It answered every question for me.

You get a HILPT and need some extra turns, you hit the key to suspend and don't change the course. You get an enroute hold, you hit the key to suspend sequencing whether or not you need to change the course (usually don'). You use it for manual course selection and ... voila! ... it suspends automatic sequencing.

Basically, it allows you to manually select a course but it always suspends automatic sequencing.

(BTW, the IFD does not suspend automatic sequencing in OBS mode; the only thing it does is allow manual course selection.)
 
midlifeflyer said:
We all ultimately find our own ways to make it click, but I never really understood the button until I began to think of it as the suspend button. It answered every question for me.

You get a HILPT and need some extra turns, you hit the key to suspend and don't change the course. You get an enroute hold, you hit the key to suspend sequencing whether or not you need to change the course (usually don'). You use it for manual course selection and ... voila! ... it suspends automatic sequencing.

Basically, it allows you to manually select a course but it always suspends automatic sequencing.

(BTW, the IFD does not suspend automatic sequencing in OBS mode; the only thing it does is allow manual course selection.)
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Yeah. Took awhile for me to get it to click when I first entered the Buttonology World. Guess it’s kinda like a what came first, the chicken or the egg thing.
 
Hang 4 said:
On the GTN, Suspend also comes into play on a hold that is part of an approach. If you need to stay in the hold, you need to suspend to avoid going down the approach after the first turn. Think of SUSPEND as suspending sequencing vs "deactivating" the GPS guidance and then it gets a bit easier mentally (at least for me)
Click to expand...

Thank you. I have had this confuse me a ton. I totally get it now.
 
Always good to download the sim for the 430/530 or the 480 and work through these issues. Practice the why/what ifs from the comfort of home.
 
Checkout_my_Six said:
so where did the word "suspend" come from? .....Lawyers
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What would you call it????

You suspend sequencing.

sus·pend
verb
1. temporarily prevent from continuing or being in force or effect.
"work on the dam was suspended"
 
Pinecone said:
What would you call it????

You suspend sequencing.

sus·pend
verb
1. temporarily prevent from continuing or being in force or effect.
"work on the dam was suspended"
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then why do so many have a problem with the word?
 
RussR said:
It's been a while, but I believe the GTNs have the turn altitude encoded into the procedure. So you should just be able to press "unsuspend" as soon as you go missed.
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Both the GTN and the GNS have support for the "course from fix to altitude" legs that may be used on a missed approach climb to altitude, but they need a baro-corrected pressure altitude input,
usually provided by a PFD that outputs baro-corrected pressure altitude.
.
 
John Collins said:
Both the GTN and the GNS have support for the "course from fix to altitude" legs that may be used on a missed approach climb to altitude, but they need a baro-corrected pressure altitude input,
usually provided by a PFD that outputs baro-corrected pressure altitude.
.
Click to expand...
I learn something new everyday from a few of the CFII's that post here. Had no idea that existed. Will have to play around with it as I have a Baro-corrected altitude source - At least I assume I do with a G500
 
John Collins said:
Both the GTN and the GNS have support for the "course from fix to altitude" legs that may be used on a missed approach climb to altitude, but they need a baro-corrected pressure altitude input,
usually provided by a PFD that outputs baro-corrected pressure altitude.
.
Click to expand...
I believe you, but in practice, on the GNS, as far as I know I have never seen an installation where the unit would provide straight ahead guidance to an altitude, then begin the turn guidance at that altitude.

But the number of GPS approaches which are NOT straight ahead in this area is fairly low, and that's mostly what I was flying when teaching instruments in this area.
 
Regarding the use of the OBS button to do the suspend/unsuspend function, a lot of the design of the 430/530 is based on the 300XL, which was in turn based on its predecessors. In the 300XL (and presumably those before it), you used the OBS a lot more than you do now.

It's been a while since I've used one (like 10 years), so this might not be entirely accurate, but I seem to remember:

- There was no provision in the units for vectors to final. You had to set the FAF as your active waypoint then you could use the OBS mode to set the final approach course to intercept. Maybe you could also do it through an "activate leg" function, I don't remember.

- It didn't know anything about holds. You'd use the OBS button to set the inbound course for the hold, and figure out how to fly it yourself.

My point is, the OBS button is little used now, but pre-GNS it was actually an important button. When the GNS series came out, it was retained, probably since "we've always had one", even though it lost a lot of its importance with the new units. I imagine the OBS button was seen as more important than a dedicated SUSP button at the time. And there's only so much room for buttons.
 
The meaning of the SUSP button varies by the UNIT and what operation is in mode. On my 480, it pretty much means do the opposite of what it would do by default.
 
It takes a lot of extra work to make something simple and intuitive. But I do wish Garmin would do it. Surely the GTN could know you’re at the end of an approach, and could simply ask “Go Missed to Published Hold?” Don’t hit the button and simply land. Hit the button and go to missed hold.
 
I’ve run into a few things while learning the GTN. Once in a while a local VOR is out of service. The missed hold for our ILS is at that VOR. When that VOR is U/S the alternate missed procedure is in effect. Unsuspending will try to take you to the normal instead of the alternate. I really need to find a GTN650 sim I can use, but I haven’t found one yet that works on an Android or MacBook. I’ve only found one for iPad and Windows.
 
Matthew said:
I’ve run into a few things while learning the GTN. Once in a while a local VOR is out of service. The missed hold for our ILS is at that VOR. When that VOR is U/S the alternate missed procedure is in effect. Unsuspending will try to take you to the normal instead of the alternate. I really need to find a GTN650 sim I can use, but I haven’t found one yet that works on an Android or MacBook. I’ve only found one for iPad and Windows.
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Yes, that is correct. Alternate missed approach instructions are not coded into the GPS database.
 
WDD said:
It takes a lot of extra work to make something simple and intuitive. But I do wish Garmin would do it. Surely the GTN could know you’re at the end of an approach, and could simply ask “Go Missed to Published Hold?” Don’t hit the button and simply land. Hit the button and go to missed hold.
Click to expand...
Isn't that pretty much what it does say? Yes it has the two options, but only one is important most of the time. If you do nothing and just landed, that's fine.
 
WDD said:
It takes a lot of extra work to make something simple and intuitive. But I do wish Garmin would do it. Surely the GTN could know you’re at the end of an approach, and could simply ask “Go Missed to Published Hold?” Don’t hit the button and simply land. Hit the button and go to missed hold.
Click to expand...
Garmin tried that early on by hanging industry standard terminology…all they did was confuse people.
 
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Checkout_my_Six said:
"learn"....that means it's not intuitive. ;)
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I disagree. "Intuitive" is in the mind of the beholder and is far more often than not based on what has been learned.

I find the simple use of a single word, "suspend" as intuitive as a red traffic signal. I don't need 6 additional words to dumb it down.
 
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