Activate Approach vs Direct-To IAF

[tsts4]

It's easy to learn what it does and never have a problem. But I'm not sure it's particular intutitive that "Activate Approach" means "only activate this part of the approach." I'm sure there have been plenty of pilots who have hit it expecting to activate the nearest available waypoint or leg of the approach, not be given a 180.


That's interesting. I can honestly say that, since I choose a transition fix closest to my route of flight, I have joined approaches places other than the transition I initially chose far more often than at that initial transition. Direct to the IF. Vectors to final. Join a segment.

In recurrent training, I've seen pilots who understand what it actually does. I have also seen pilots who Activate Approach expecting some intermediate leg or waypoint to become active and are surprised when the AP turns them away from the approach, as in the graphic I posted earlier. My sample is small, but if Garmin is bothering to change it, I suspect there's a reason.

It’s a method (that works for me, training primacy and all that), not a panacea and just one tool in the tool box. As you stated many times, you need to know how to play the cards you’re dealt vs trying to force every situation into a single one process to rule them all method.

 

[WDD]

Interesting. For me, it's also intuitive to load the approach waiting for ATC. When ATC says ".... do direct to WOJOX" I activate the approach, then simply scroll on the flight plan and hit "Direct to WOJOX". I see it as first, I want to do this (Activate), and second I want to go here (Direct to). By separating the two it makes it clearer. If Activate also happens to load up where I want to go, a nice bonus.

If things change again or I've done something wrong, I just pull up "Procedures", hit "Activate VTF". To me, "VTF" means "schlep this way to the get on the approach, no specific fix".

 

[midlifeflyer]

If things change again or I've done something wrong, I just pull up "Procedures", hit "Activate VTF". To me, "VTF" means "schlep this way to the get on the approach, no specific fix".

LOL!

To me, "VTF" means "I screwed something up and I'm so close to the FAC that it's the quickest way to fix it."

 

[midlifeflyer]

It’s a method (that works for me, training primacy and all that), not a panacea and just one tool in the tool box. As you stated many times, you need to know how to play the cards you’re dealt vs trying to force every situation into a single one process to rule them all method.

Well, sort of. I tend to favor SOPs that work in more situations than less to build both mental and physical muscle memory. That's pretty close.

More to the point, I've said even more times that my First Commandment of flight instruction is, "Thou shalt not change a pilot's procedure that works just because you like (likest?) one better." But I will test to make sure it works. This one's easy to check.

 

[dmspilot]

When ATC says ".... do direct to WOJOX" I activate the approach, then simply scroll on the flight plan and hit "Direct to WOJOX".

It seems like you don't actually understand what activate does then, since your first step is unnecessary.

 

[midlifeflyer]

It seems like you don't actually understand what activate does then, since your first step is unnecessary.

I didn't catch that. Yeah,

When ATC says ".... do direct to WOJOX" I activate the approach, then simply scroll on the flight plan and hit "Direct to WOJOX".

the highlighted part is all that's needed to activate the approach.

But maybe his SOP is to activate ever approach twice, even if not necessary?

 

[midlifeflyer]

the highlighted part is all that's needed to activate the approach.

Just to be sure everyone is on the same page about what @dmspilot and I are talking about, this is the RNAV (GPS) Y 5R at RDU. I chose it and loaded it from OTTOS because of all the waypoints before reaching the FAF. I chose to do it in a GNS to show it's been like this for a long time.

 

[Hang 4]

And in that example, if you were past OTTOS and hit Activate Approach, your GPS would command a u-turn. No big deal if you're in HDG mode, but would be a bit of a surprise in Nav Mode. Even if you were hand flying, it would be pretty confusing.

 

[midlifeflyer]

And in that example, if you were past OTTOS and hit Activate Approach, your GPS would command a u-turn.

Yep. The graphic talks about the different ways the approach sequence becomes active, in response to the semi-redundant "Activate" then go-to comment, but that U-turn is mentioned at the very top. Between PECIT and PURME and press "Activate Approach," you are sent back to OTTOS.

 

[StraightnLevel]

OK, I have to ask:

Why would you ever do anything other than “Load Approach” and let it activate when you enter - regardless of how or where you enter the approach?

 

[midlifeflyer]

OK, I have to ask:

Why would you ever do anything other than “Load Approach” and let it activate when you enter - regardless of how or where you enter the approach?

I don’t know what you mean

If you are referring to my graphic, the flight plan sequence is currently direct to the airport. That won’t change unless the pilot tells the unit to do something else.

 

[Hang 4]

OK, I have to ask:

Why would you ever do anything other than “Load Approach” and let it activate when you enter - regardless of how or where you enter the approach?

In @midlifeflyer example, you are "activating" by any of the 8 choices in his graphic. If you don't either activate the leg or hit "direct to", you'll fly through the approach without turning. The difference is you aren't just hitting a button called activate, but giving specific direction on how to join the approach, which also "activates" it.

 

[WDD]

the highlighted part is all that's needed to activate the approach.

But maybe his SOP is to activate every approach twice, even if not necessary?

In terms of fewer button pushes, hitting "Direct To" is faster.

In retrospect, what I do is perhaps more of habit and my unique panel set up. I have two GPS units, a GTN 650xi and a GNC 355. I keep the GTN 650xi on the flight plan page and generally enter the commands there. I keep the GNC unit on the map screen and don't interact with it as I do the GTN. Thus, after "Activate" I go back to the flight plan screen anyway. I see I'm going to the IAF, all is good. If I need to change, I change. TBH, not sure why I would need to change. If I do have an urge to hit the Direct To button, maybe it's just classical conditioning, like hitting the elevator button more than once.

The habit / process does however serves me well in the ATL area for Arrivals, where about a quarter of the time I get one. Interestingly, despite what Martha and John taught, I've never started at any of the published entry points. It's always "Fly Buckhead 3, go to ACME". Looking at the chart, I select and load the Arrival with an entry point that eventually includes "ACME", and then I hit Direct to ACME.

Net Net, what I do works, but perhaps is an unnecessary double tap/double check. Always looking to learn, and I'll do some VFR practice with the Approach process and just "Direct to" on a loaded by not activated approach. It will either be can teach an old dog or new trick, or just best to let sleeping dogs lie.


EDIT / BONUS: Upon reflecting, I think I'm just a "Direct To" fan / cult member. When departing ATL, I load the flight plan I'm cleared for, go in the air, and it changes under 5 minutes. I start with vectors, then told to go to "EFGH" when I was originally given "ABC". Then another skip in the flight plan fix list. Then direct to destination. In the air when approaching a nice visual approach for Valparaiso (Chicago area), I'm usually told "Direct to ONX" which I assume is to get me east for some Gary or Midway traffic. Usually before I get there I'm turned direct to Valpo.

Net Net, maybe I live a lot in the "Direct To button pushing" world.

 

[midlifeflyer]

In @midlifeflyer example, you are "activating" by any of the 8 choices in his graphic. If you don't either activate the leg or hit "direct to", you'll fly through the approach without turning. The difference is you aren't just hitting a button called activate, but giving specific direction on how to join the approach, which also "activates" it.

I’ve never tried to see before, so for jollies, I put that route into the GTNxi iPad trainer. The approach actually does self-activate. But here’s what happens.

It treats RDU as a waypoint, not a destination. So… on AP, the airplane will fly direct to RDU, then sequences back to OTTOS to join the approach back into RDU. Since it will anticipate the ~180 at RDU, it will actually never make it to the airport the first time, and the faster you go, the earlier the turn back to OTTOS before reaching RDU.

For the Avidyne folks, it works differently in the IFD. It will get all the way to RDU and stop sequencing.

 

[midlifeflyer]

Might have been directing that question to my post, which is a legitimate question IMHO.


In terms of fewer button pushes, hitting "Direct To" is faster.

In retrospect, what I do is perhaps more of habit and my unique panel set up. I have two GPS units, a GTN 650xi and a GNC 355. I keep the GTN 650xi on the flight plan page and generally enter the commands there. I keep the GNC unit on the map screen and don't interact with it as I do the GTN. Thus, after "Activate" I go back to the flight plan screen anyway. I see I'm going to the IAF, all is good. If I need to change, I change. TBH, not sure why I would need to change. If I do have an urge to hit the Direct To button, maybe it's just classical conditioning, like hitting the elevator button more than once.

The habit / process does however serves me well in the ATL area for Arrivals, where about a quarter of the time I get one. Interestingly, despite what Martha and John taught, I've never started at any of the published entry points. It's always "Fly Buckhead 3, go to ACME". Looking at the chart, I select and load the Arrival with an entry point that eventually includes "ACME", and then I hit Direct to ACME.

Net Net, what I do works, but perhaps is an unnecessary double tap/double check. Always looking to learn, and I'll do some VFR practice with the Approach process and just "Direct to" on a loaded by not activated approach. It will either be can teach an old dog or new trick, or just best to let sleeping dogs lie.

The only real issue I can see with the “Activate then direct” method, other than the unnecessary extra button tap, is if the loaded transition is different than the Direct waypoint. Even then, unless you delay the Direct part, while the AP will first turn to the loaded transition, it should only be momentary. You probably don’t even notice it.

And yes, despite John and Martha, joining a STAR other than at a published transition is quite common. It happens with SIDs too.

 

[midlifeflyer]

The habit / process does however serves me well in the ATL area for Arrivals, where about a quarter of the time I get one. Interestingly, despite what Martha and John taught, I've never started at any of the published entry points. It's always "Fly Buckhead 3, go to ACME". Looking at the chart, I select and load the Arrival with an entry point that eventually includes "ACME", and then I hit Direct to ACME.

You've probably seen one of my "GPS Tasks Pilots Don't Know How to Do" posts. You've just described one of them and you clearly know how to do it!

 

[StraightnLevel]

If you are referring to my graphic, the flight plan sequence is currently direct to the airport. That won’t change unless the pilot tells the unit to do something else.

Agreed.

I have a 430W. When I load the approach, I select the most likely IAF, or whatever point ATC calls out. Once it is loaded, it will automatically activate when I reach any point from the selected fix or further into the approach. If ATC changes a vector or approach fix, I don't have to re-load the approach - it will pick it up and activate when I reach the path/fix.

 

[midlifeflyer]

Agreed.

I have a 430W. When I load the approach, I select the most likely IAF, or whatever point ATC calls out. Once it is loaded, it will automatically activate when I reach any point from the selected fix or further into the approach. If ATC changes a vector or approach fix, I don't have to re-load the approach - it will pick it up and activate when I reach the path/fix.

My process is pretty much the same as yours. I'm sure you know this but for clarification for those who don't...

It doesn't automatically activate when you "reach" any point. It automatically activates when you "tell it" to go to that point or leg by using D→ or activating the leg. What's the difference? Well, in my example graphic (approach loaded, not activated), all I've "told it" to do is go direct to RDU, I can cross right over - "reach" - OTTOS, BEICH, RATTY, etc, and the approach sequence will not activate.

 

[MauleSkinner]

And yes, despite John and Martha, joining a STAR other than at a published transition is quite common. It happens with SIDs too.

Back in my Citation days I would be vectored off of and then rejoin a STAR several times. One of the benefits of flying an airplane with a Slow Moving Vehicle triangle on the back.

John and Martha, having owned a Citation, should be quite familiar with that.

 

[midlifeflyer]

Back in my Citation days I would be vectored off of and then rejoin a STAR several times. One of the benefits of flying an airplane with a Slow Moving Vehicle triangle on the back.

John and Martha, having owned a Citation, should be quite familiar with that.

True dat! I personally have no idea what John and Martha actually teach about SIDs and STARs beyond what @WDD related. But there are often difference between what is taught about procedures and the real world nuance of flying those procedures.

 

[Dixiebluesky]

This is like arguing whether it is best to hit 60 or 100 on the microwave, you are doing the exact same thing and will fly the exact same approach.