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DAL488

Trouble arming APP in ILS approach, and LOC/G/P instead of LOC/G/S

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Hi all,

I've had the same problem on the last two flights.  When I try to fly an ILS approach, it's not working as expected.  Basically, I have the ILS freq/course set on both NAV1 and NAV2.  I have double checked this and it also matches the FMC.  I have it in APP mode, and it intercepts the LOC (I'm below the G/S).  But once I intercept the G/S, APP kicks off, and PFD states "LOC/G/P" and it tracks the G/P in VNAV mode (I guess).  I try to re-engage APP to track the G/S instead of G/P, but it won't let me. 

 

I don't understand why I can't track the ILS G/S.  Granted, in both cases I used LNAV/VNAV to intercept the LOC, and also descend to FAF altitude, but shouldn't it let me fly the ILS?  I definitely have selected the ILS approach within the FMC.

 

Any awareness/knowledge of this, please let me know.

 

Thanks,

James

 

P.S. - I did a quick test flight, and used V/S mode to get to FAF altitude, and it then went into ALT HOLD.  From here, I was using HDG SELECT to intercept the LOC, and I armed APP mode.  It intercepted both LOC/G/S properly. 

 

 

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I don't understand why I can't track the ILS G/S.  Granted, in both cases I used LNAV/VNAV to intercept the LOC, and also descend to FAF altitude, but shouldn't it let me fly the ILS?  I definitely have selected the ILS approach within the FMC.

 

Did you select the ILS approach, and not an RNAV? Additionally, does the sim actually have a glideslope to follow (my home airport only had a LOC at the time FSX was released, so I had to add the GS in later through ADE). GP infers you're using IAN, which is RNAV-based.

 

 

 


P.S. - I did a quick test flight, and used V/S mode to get to FAF altitude, and it then went into ALT HOLD.  From here, I was using HDG SELECT to intercept the LOC, and I armed APP mode.  It intercepted both LOC/G/S properly. 

 

Same airport/approach?

 

 

 


Thanks,
James

 

Full names in the forum please - first and last.

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Yes, absolutely selected the ILS approach.  It was KDEN 34L the first time and KMDW 4R the second.  Both full ILS approaches with G/S

 

James White

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Yes, absolutely selected the ILS approach.  It was KDEN 34L the first time and KMDW 4R the second.  Both full ILS approaches with G/S

 

Knowing how DEN likes (and has the room for) very long stacks on the LOC (i.e. "has very long finals"), might it be the case that you armed APP prior to receiving both a LOC and GS indication? The systems will default to IAN if signals aren't being received when APP is armed. You can modify signal behavior in a program like ADE (or by downloading a new BGL for the airport (commonly called an AFCAD) such that it has a longer range. Larger Class B airports have pretty powerful arrays that can go out quite a while (DEN's go out to something like 30nm, usable), whereas local airports have less powerful and shorter distances, further still, FSX's are all hard coded to a shorter value than these larger airports (20ish nm I think?).

 

This probably didn't happen at MDW because the STARs are arranged differently, and the finals are a lot shorter.

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I doubt I did, but that's certainly a possibility.  The systems were on IAN for some reason and I couldn't get them to switch back to ILS G/S.  So, it could be that I inadvertently armed APP to early. 

 

I read the manual a little while ago, and I'm just going to make sure I use VOR/LOC first, to capture the LOC and then engage APP once I have the G/S. 

 

Thanks for the help.

 

James White

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I doubt I did, but that's certainly a possibility.  The systems were on IAN for some reason and I couldn't get them to switch back to ILS G/S.  So, it could be that I inadvertently armed APP to early. 

 

I believe the way to "reset" the system and kick it out of IAN is to change off the freq and back on to it.

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