B

buz

Well Known Member
Questions on coupled ILS approach?(GRT)

I could not find this discussed recently.

When flying a coupled approach with the 430w and trutrak gsvg and grt HX how do you guys set everything up? Can someone share their cheat sheet?

I can get it to work but when going missed it does not seem to automatically go to to the mahp (while still coupled).

Thanks.
 
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missed

the GRT will not change anything when the missed softkey is pushed except the altitude you have entered because the 430W has not changed the next waypoint and will not until you press the suspend on the 430w when it appears, it does not appear until you are close to the airport
 
Yes I understand that. I did wait and also press suspend on the 430. Its at this point I get messed up. Do I have to change the NAV mode to GPS-1(430) to have it fly to the mahp while coupled?

Also it seemed like it dropped the A/P while mashing buttons for the missed.
 
If your question is specifically about the missed approach and if you want to use the published missed, then you will need to press the "OBS" button to take it out of suspend. I believe this will work only if you have reached the missed point (airport) and not sooner. Of course the approach needs to have been loaded in the 430 but I think you already know this.

The "missed" function that is part of GRT will simply fly the airport heading and to the preset altitude which is obviously different then the published missed. Also, if memory serves me right, the GRT will automatically go to the heading mode once passed the missed approach and if so, you need to make sure that GRT is in the ENAV or GNAV mode if/when using the 430 for the missed approach.

Other things that I have learned regarding the ILS approach with GRT & TT, set the A/P to heading and select GPSS and GPSV on your TT, while the ILS approach has been loaded on the 430. Fly the vectors as given with the heading & altitude being driven/controlled by the GRT. Prior to reaching/joining the Loc, arm the GRT for the ILS approach. Once the needle becomes active which typically you are given the clearance to join the Loc? then GRT automatically switches to ENAV and will center the needle like no body's business. You can sit back, drink your coffee and just control the speed/flap.
 
A Word of Caution

Your Garmin goes into suspend mode at miss for a very good reason - many approaches require a climbing turn to an altitude or a straight ahead climb to an altitude before proceeding to the MAP. In the soup at 200 AGL is not the time to be pushing buttons and setting heading bugs. Fly the airplane.
Terry, CFI
RV-9A N323TP
 
terrykohler said:
Your Garmin goes into suspend mode at miss for a very good reason - many approaches require a climbing turn to an altitude or a straight ahead climb to an altitude before proceeding to the MAP. In the soup at 200 AGL is not the time to be pushing buttons and setting heading bugs. Fly the airplane.
Terry, CFI
RV-9A N323TP
Click to expand...

I agree with Terry. In an ideal and perfect future world, we will tell the airplane to fly an approach, and when we get to the missed point, we will tell it to safely fly a miss - with a single command. Personally, I am not comfortable that the technology is there yet - there are too many variables, and the structure of the "certified" systems do not allow the flexibility for programmers to create what needs to be done in our experimental stuff - yet. The day will come when we can really monitor and issue single commands to execute complex phases of flight, but until that happens, don't get fooled into thinking we are more advanced than we are.

I always hand fly th miss because I am never quite sure that the logic is going to do it the way I expect, and 200 feet off the ground at speed is no place to be in doubt. I move in and out of complex simulated worlds, and the most dangerous thing is to forget that the real world is totally unforgiving.

Paul
 
Ironflight said:
I agree with Terry. In an ideal and perfect future world, we will tell the airplane to fly an approach, and when we get to the missed point, we will tell it to safely fly a miss - with a single command. ...
Paul
Click to expand...

Actually, that's exactly how the Chelton units work. While I agree we should never rely entirely on the technology (we still need to brief the plate and know what we're supposed to be doing) I wouldn't hesitate a moment using the Chelton's miss feature anymore than I'd hesitate using its GPS or ILS approach to minimums.

Having used both the G1000 and the 430 I find the Chelton MUCH easier and more intuitive to use. I much prefer it to either of them. Unfortunately, it's not sold to the experimental market anymore.
 
Ironflight said:
I always hand fly th miss because I am never quite sure that the logic is going to do it the way I expect, and 200 feet off the ground at speed is no place to be in doubt. I move in and out of complex simulated worlds, and the most dangerous thing is to forget that the real world is totally unforgiving.

Paul
Click to expand...

I agree that flying the miss from the get-go thru A/P is very risky and can be dangerous. My personal practice is to decouple it from the A/P about 500' above the minimum and hand fly it. If miss to be executed, I will hand fly it to the safe altitude and then possibly start using the A/P.
I think the bigger danger is that not all the setting could be as intended. In one practice approach, after the miss I coupled it to the A/P and a destination on the GPS but the GRT was still on A/P heading and start turning in a direction that I was not expecting at all. That could have been certainly a dangerous situation if low to the ground and in IMC.
 
Exactly

That's why I stick with the simple wing leveller TT and ALTRAK altitude hold AP. When flying the ILS I will simply set the TT to the final approach heading. In other words I don't couple the the approach. I find this keeps me engaged enough while keeping me centered on the approach.

Frank
 
GRT should clean this up

Ironflight said:
...because I am never quite sure that the logic is going to do it the way I expect...
Click to expand...

And to this point, I would love to see GRT clean up their missed approach functionality or at least the documentation. All the EFIS's have their little pain points, but as much as GRT pitches their HX as a "solid IFR" EFIS, I think thier missed approach functionality/documentation is a little sub par.

As I was getting my IFR legs back, I posted a very similar question on the GRT message board. GRT's documentation about how to fly the missed approach is confusing and contradicts itself. Everybody that responded to my question gave a slightly different description of how it works. I think this speaks to Paul's point of never really being sure what it's going to do.

In one part of their user's guide, it says "If the pilot changes the LAT A/P mode to HDG after LOC capture, the ARM (CAPT) is automatically set to OFF." But then all over the place, it talks about setting up the missed approach by choosing the AP mode AFTER CAPTURE. So it says if you change the LAT AP mode after capture, you'll kill the approach. Then it turns around and says to choose a LAT AP mode after capture to set up the missed approach... ?????

IMHO, upon pushing "missed" on the GRT, the easiest thing to do would be have the LAT AP mode go into HDG mode and set the heading to the current heading. That way, at least the wings will stay level until the pilot says otherwise. The climb to the missed approach altitude set by the pilot will have started as well. It still requires some user input, but I think everybody would be happy for now to have it be consistant and predictable.

Dave
 
This can be done safely.

I agree that pushing buttons at 200' in the soup is not cool UNLESS you know exactly what is going to happen. I also believe that decoupling the AP and transitioning to hand flying at 200' in the soup can be just as dangerous unless one is very proficient. The missed approach is actually in the Garmin db as a gps track, so one needs to push the button on the 430 to GPS (it will be in VLOC mode for the ILS). You don't have to wait for the missed approach point to do this if you elect to get out of the situation earlier than 200' or MDH. Make sure you set your missed approach altitude in your altimeter setting AFTER you are inside the marker or have captured the glidslope. Once the GPS button is pushed the airplane will now climb, and fly the GPS track back to the missed hold waypoint. Go out and try it VFR MANY times first, and you will see that it works very nicely.

Vic
 
vic syracuse said:
I. The missed approach is actually in the Garmin db as a gps track, so one needs to push the button on the 430 to GPS (it will be in VLOC mode for the ILS). You don't have to wait for the missed approach point to do this if you elect to get out of the situation earlier than 200' or MDH. Make sure you set your missed approach altitude in your altimeter setting AFTER you are inside the marker or have captured the glidslope. Once the GPS button is pushed the airplane will now climb, and fly the GPS track back to the missed hold waypoint. Go out and try it VFR MANY times first, and you will see that it works very nicely.

Vic
Click to expand...

Vic,
I have tried this a number of times and also duplicated using the Garmin simulator. My experience has been that Garmin 430 will follow the flight plan which has the instructions for the missed approach only if the runway (missed approach) has been reached. If I press OBS prior to reaching the runway? it will suspend the flight plan and not go to the next leg which is the published missed.

If you have the simulator, you can try it for KPVF or KHMR, either ILS or GPS approach. If you find a way that it will follow the publish missed prior to reaching the runway, I appreciate it letting me know as I have been baffled about this and even put a post about it without any resolution.
 
what I have learned, ILS

After many gallon of avgas this is what I have figured out in my plane, with my equipment wired the way it is?!

Put destination airport in direct to in the 430w
Loaded and activated ILS approach in 430w, (vectors to final)
set GRT LAT A/P in HDG mode with heading to intercept LOC
set GRT NAV to NAV 1(430w VOR)
ARM ILS in GRT- set/verify inbound course on GRT(was prompted for this)
set up sl=30 with second vor to see cross radials

when the LOC was captured and the plane turned inbound, the LAT A/P automatically changed from HDG to ENAV, the g/s was captured and down we go

at this time you need to have the missed approach altitude set to the published missed alt

from here to missed you do nothing except monitor, slow down, flaps, ect.

to go missed I first press the missed softkey on the GRT, (by pushing missed it automatically changed to HDG mode, set the HDG to present course, and initiates a climb of 500 fpm(flashes this in red))

once you get to the appropriate altitude and or location on the missed procedure you press the suspend button on the 430w, set the GRT LAT A/P to GNAV and then the plane will finish climbing to the altitude set and fly to the mahp as published and flys the hold without further action. you can then reactivate the approach and do it all again.

I also changed NAV 1 to GPS 1 on the GRT( I don't think you have to do this, it was nice because it took away the loc/ g/s bars that were flailing around on the flight screen)
This procedure worked for me, the plane stayed coupled to the autopilot the entire time and is a lot easier to do than it sounds.

Does this sound like what everyone else has to do with similar equipment?
 
Bavafa said:
I have tried this a number of times and also duplicated using the Garmin simulator. My experience has been that Garmin 430 will follow the flight plan which has the instructions for the missed approach only if the runway (missed approach) has been reached. If I press OBS prior to reaching the runway? it will suspend the flight plan and not go to the next leg which is the published missed.
Click to expand...

Take a look at the text on the screen immediately above the OBS button. If it says "SUSP", it means that automatic waypoint sequencing has been suspended, and pressing the button will cancel out of the SUSP state and return to normal waypoint sequencing. If you press the OBS button before you see the "SUSP" label, you're telling the unit to do something else entirely. For more information, take a look at pages 5 and 18 in the GNS 430W Quick Reference Guide.

One other thing worth mentioning: My CFII always taught me, as I'm sure yours did as well, that if you decide to go missed before reaching the missed approach point, you'd better keep flying straight ahead until you cross the MAP! There are no obstacle clearance guarantees if you turn back outbound when you still have miles to go before crossing the missed approach point.

mcb
 
Matt is dead on here. Executing the missed prior to the MAP does NOT guarantee obstacle clearance, and yes, wait until the SUSP is displayed before pressing GPS. I will go out and verify it again this week end.

VIc
 
mburch said:
One other thing worth mentioning: My CFII always taught me, as I'm sure yours did as well, that if you decide to go missed before reaching the missed approach point, you'd better keep flying straight ahead until you cross the MAP! There are no obstacle clearance guarantees if you turn back outbound when you still have miles to go before crossing the missed approach point.

mcb
Click to expand...

Amen to that one!!! I have seen people practicing approaches go missed early and start the missed procedure that might kill them....Never start the procedure other than climb before the MAP!!! You can also get into trouble if you are using the timer to find the MAP if you do not maintain your GS during the climb. You may not be past the MAP if you go missed early and climb too slow...flying into a tower/hill/building while in IMC is not my idea of fun!!
 
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buz said:
After many gallon of avgas this is what I have figured out in my plane, with my equipment wired the way it is?!

Put destination airport in direct to in the 430w
Loaded and activated ILS approach in 430w, (vectors to final)
set GRT LAT A/P in HDG mode with heading to intercept LOC
set GRT NAV to NAV 1(430w VOR)
ARM ILS in GRT- set/verify inbound course on GRT(was prompted for this)
set up sl=30 with second vor to see cross radials

when the LOC was captured and the plane turned inbound, the LAT A/P automatically changed from HDG to ENAV, the g/s was captured and down we go

at this time you need to have the missed approach altitude set to the published missed alt

from here to missed you do nothing except monitor, slow down, flaps, ect.

to go missed I first press the missed softkey on the GRT, (by pushing missed it automatically changed to HDG mode, set the HDG to present course, and initiates a climb of 500 fpm(flashes this in red))

once you get to the appropriate altitude and or location on the missed procedure you press the suspend button on the 430w, set the GRT LAT A/P to GNAV and then the plane will finish climbing to the altitude set and fly to the mahp as published and flys the hold without further action. you can then reactivate the approach and do it all again.
Click to expand...

This is exactly how mine behaves and are the procedure that I use. I just don't have to change the Nav on GRT since my 430 is the source for GPS/VOR thus stays on 430 for the sourse.


mburch said:
Take a look at the text on the screen immediately above the OBS button. If it says "SUSP", it means that automatic waypoint sequencing has been suspended, and pressing the button will cancel out of the SUSP state and return to normal waypoint sequencing. If you press the OBS button before you see the "SUSP" label, you're telling the unit to do something else entirely. For more information, take a look at pages 5 and 18 in the GNS 430W Quick Reference Guide.

One other thing worth mentioning: My CFII always taught me, as I'm sure yours did as well, that if you decide to go missed before reaching the missed approach point, you'd better keep flying straight ahead until you cross the MAP! There are no obstacle clearance guarantees if you turn back outbound when you still have miles to go before crossing the missed approach point.

mcb
Click to expand...

Agree completely and perhaps that is why 430 does not give you the option to excute the miss prior to reaching the missed point.
 
Bavafa,

I too am using a 430 for the source, what did you mean by changing the NAV on the GRT?

My NAV 1 and GPS 1 are both from the 430. NAV is the vor/loc signal and GPS is gps signal.
 
buz said:
Bavafa,

I too am using a 430 for the source, what did you mean by changing the NAV on the GRT?

My NAV 1 and GPS 1 are both from the 430. NAV is the vor/loc signal and GPS is gps signal.
Click to expand...

Jamie,
After re-reading your steps, I think we are saying the same thing here. It is that I set the GRT for the 430 as the source for Nav and never need to change it (VOR or GPS) unless I want to test my second source which is another GPS, just to make sure it is still working OK.
One thing that I like to get improved is the rate of turn while it is in the heading mode. If I am insturcted to change 10 degrees left or right, the A/P takes its sweet time to make that 10 degrees.

Incidentally I tested this to see what happens if my first source (430) dies while is providing the source for navigation (not an approach). After manually shutting down 430, the GRT automatically switched to the second Nav and just continued with the heading.
 
Mehrdad,

What is your second NAV? So if my sl-30 is tuned to the LOC and the 430 dies it will continue on the approach?

My heading gain is 1.1 and seems to be about standard rate turns.
 
buz said:
Mehrdad,

What is your second NAV? So if my sl-30 is tuned to the LOC and the 430 dies it will continue on the approach?

My heading gain is 1.1 and seems to be about standard rate turns.
Click to expand...

Jamie
My second nav is the built-in GPS. That would be an interesting test with your second VOR. Let us know if you try it and see how it will do.

In regards to the rate of turn, that might be an issue with the TT setting. I need to look more into it and the version I have in mine. Do you know what is your bank angle on your TT set to?
 
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Mehrdad,

I will try this and report back. I will check the TT setting also.
I will be out of town for about a week and will try when I get back.

Thanks
 
Mehrdad,

Your second nav is the internal GPS? How would it continue an ILS approach with that?
 
buz said:
Mehrdad,

Your second nav is the internal GPS? How would it continue an ILS approach with that?
Click to expand...

Not a ILS or GPS approach. I tried it during a "go to" way point (destination). I am fairly sure that it will not do a GPS approach as it does not have the instructions, unless (perhaps) it happens on the last leg of the approach which would be the airport itself. Will try it on a GPS approach and report back.
 
OK, that makes sense. It will be interesting to see if while using vor 1 it would switch and use vor 2 if tuned to the proper freq. and continue on the LOC and G/S.
 
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