I run through the tutorial and had no problem using the LOC and APR. Now I have done 5 more flights and even though the frequencies are tuned the LOC and APR fail to engage.. The GS and Loc show up in the PFD as active? Help?

the LOC and APR fail to engage..

Did you press the LOC and APP button or just the APP button to arm them? When armed LOC and G/S should appear on the FMA in white. They will change to green upon capture.

I press the LOC first per the manual but it never lights up the button. Neither button will engage. Tired again last night and the same thing. I guess I will try the tutorial again and see if that works. Stumped

Are you sure have the runway assigned in the FMS?

 

 

I press the LOC first per the manual

 

Per the manual? It isn't required to hit LOC first at all. You can press APP directly in most cases.

 

 

 

Neither button will engage. Tired again last night and the same thing.

 

Did you select an ILS approach in the FMC? Are you sure there's an ILS freq in the sim that matches the data in the FMC?

 

 

 

Stumped

 

Full real names in the forum, please.

What altiude were you at and how far from the airport?

 

Did you have the FD or AP on?

 

Were you on an intercept heading of less then 120 (80) degrees to the localizer when you pressed LOC or APP.

 

As said, there is no need to press the LOC first then APP.

You can just press APP alone.

But you have to be on an intercept heading of less then 120 degrees for the LOC to CAPTURE and less then 80 degrees for the GS to CAPTURE.

 

(I think in the PMDG777 it will not arm either unless within those parameters, but that is acually not programmed correctly).

EDIT:better said, that IF my memory serves me right and if the LOC/APP switch are programmed like that, then according to the book this is not quite right)

 

The LOC button is mainly to fly a LOC approach.

It can also used however be to capture the LOC while delaying the GS capture untill you are lower (descending with speedbrakes to get below the GS) and have extended to at least flaps 5 before GS capture.

 

 

(I think in the PMDG777 it will not arm either unless within those parameters, but that is acually not programmed correctly).

 

Can you be more specific about this? Have to know if I should be chasing something down or not...

I am not at home at the moment otherwise I could chase it down myself, but I could swear I have seen cases where the LOC/APP would do nothing.

 

According to the book (chapter autoflight under the description of the switches) the switches should allways arm but LOC and GS will not engage unless with in the parameters I described.

 

I cant remember last time I tried this on purpose in the real thing. So I have to go by the book on this one and a possibly incorrect memory of the simulation.

 

We allways wait with Arming the Loc/GS untill the ILS is positively tuned, identified and the deviation pointer is displayed at the correct side (SOPs).

Can you be more specific about this? Have to know if I should be chasing something down or not...

I replied and also edited my post a little.

 

You are right....my initial post was a bit too definite for something I am not 100% sure about.

I might also be confusing this with Lnav not wanting to arm when the "not on intercept heading" displays.........but there was something there.

Yes, I will add exactly what I have done:

 

1. Request the route

2. Load the route

3. Select SID/STAR including a valid ILS approach

4. Load wind data

5. Flaps 5 FMS, CG%

6. Activate

7. Both FD on and LNAV VNAV

8. Fly route

9. When on an intercept path to LOC or on final, press LOC and OR APP

 

Notes: The ILS Frq. is in the PFD, top left so I know I have the FMS setup. The carrots are live as well. In the tutorial it says that boeing states to select LOC first.

 

 

Chris Chiozza

on the fmc should that be set for auto tune or manual tune

just got home and checked real quick.

 

The PMDG777 LOC and GS can be armed from anywhere.......I just did so on downwind (flying 180 degrees opposite to the inbound course.

So that is all good.

 

 

It was the Lnav thing I was mixing things up with (I just tried that as well).

 

My bad, sorry for the confusion.

 

PMDG777 Lnav will not let you arm Lnav unless you are on an intercept heading to the active (=magenta, not white) waypoint.

You will get the "not on intercept heading" message which is correct, but what is wrong is that you cant ARM Lnav at all like that.

It should still arm and then you can adjust heading as required to capture the Magenta line where you want it, at which point Lnav should then change from LNAV (white) to LNAV (GREEN).

 

 

To Ciozza......are you by any chance trying to capture the LOC while flying in Lnav?

try it from HDG SEL please and report.

 

 

on the fmc should that be set for auto tune or manual tune

 

Autotune.  If there is a manually tuned frequency/course in NAV/RAD under PARK, you might need to delete it using the CDU Delete key before it will autotune.  It is possible that the OP's problems are due to a wrong frequency being manually tuned.  If the freq is for a nearby localizer/GS, the GS & LOC indicators could be alive but you would never intercept either since you would be aiming to intercept a different runway approach.

 

 

 

To Ciozza......are you by any chance trying to capture the LOC while flying in Lnav?
try it from HDG SEL please and report.

 

I intercept from LNAV (and VNAV) all the time w/ no problem, except that sometimes LNAV will turn me before I get to the LOC course.  Then I never intercept it.  In that case I use heading select to give it a little jog over to the localizer path.  So that could be the OP's issue - it never intercepts the loc and usually this will prevent it from descending on the GS.

 

I did just read somewhere that LNAV is not supposed to be used for localizer intercept for this reason.

 

Mike

I think I tried to use the heading to intercept the approach but I will try again.

except that sometimes LNAV will turn me before I get to the LOC course

I assume the waypoint that the aircraft turns before is part of the ILS Approach. What happens at the next waypoint on the ILS Approach?