Archived

This topic is now archived and is closed to further replies.

geomikknew

ILS Landing problem

Recommended Posts

I am using Radar Contact. RC gives me vectors to the final approach course. I engage VOR/LOC & the PMDG 737NGX turns onto the approach course. Both Flight Directors are on, the approach course is set, both radios are tuned to the proper frequency. The FD shows VOR/LOC. I am below the glideslope. Autopilot is set to CMD A. The FD slows MCP speed, ALT ACQ. At about 10 miles from the airport, I press APP on the MCP. Nothing happens & the aircraft continues toward the runway, passing above the glideslope. What am I doing wrong?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Make sure GlideSlope is turned on in the FMC. I think it's on the same page you set you approach flaps and reference speed. This drove me crazy one night for about and hour. Theres a thread on it if you search around a bit.

Share this post


Link to post
Share on other sites

The glideslope diamond is above the level line (I am below the glideslope), but then moves down to the bottom & the aircraft does not descend. The problem is that pressing APP on the MCP does not engage approach mode.

Share this post


Link to post
Share on other sites

Hi, make sure you've selected the glidescope to ON in the APPROACH REF page. If you select a STAR for arrival, make sure you select the ILXX (where XX is the runway designator). I'm not sure if you select runway XX in the STAR page, the AP will descend on the glidescope. (=reply imnsims2). If you select ILSXX in the STAR page, the problem should be solved.

Share this post


Link to post
Share on other sites

I am having a ILS landing problem also but a little bit different. Still allow me to (mis)use this thread. LOL.gifI have since last thursday (that is before applying the SP!, so this has nothing to do with) problems with autoland on ILS.The approach is looking good. The Loc is captured and followed. The G/S is capatured and followed (so this is different from the orignal poster) but somehow the G/S doesn't always take me to the threshold. I end up too high and need to disengage AP and land manually (which is though if you are already high over treshold depending on runway length.This is not always happening. sequence of events1. Flight from EHAM to ENBR with STAR (no atc guidance) =====> came in too high2. Flight from EHAM to UMBB without STAR (atc vectoring) ======> came in too high3. Flight from EHRD to EHAM (without flightplan,ATC, manually tuning NAV radio's) ====> perfect4 Flight from EHRS to EHAM with STAR (no atc, but deviating from route) ===> perfect5. Flight from UMBB to UKLR (flightplan under fsx atc, no star) ====> perfect6. Flight from UKLR to LIMC (flightplan under fsx. atc, no star)===> came in too highThe approach page always shows proper navigation freq's and G/S on in green.What am i doing wrong?

Share this post


Link to post
Share on other sites

You need to sign your full name to your posts on these forums.

The glideslope diamond is above the level line (I am below the glideslope), but then moves down to the bottom & the aircraft does not descend. The problem is that pressing APP on the MCP does not engage approach mode.
What exactly do you mean "does not arm approach mode"? There is no approach mode, there is VOR/LOC and G/S. If you mean VOR/LOC would work but not G/S, then there is a nasty bug that still hasn't been fixed in SP1. Say you fly an ILS once, go around, then fly the same approach again, G/S won't arm anymore (probably there are other conditions that will trigger this annoying behavior but this is one of them, as arming VOR/LOC and G/S is completely independent from whatever approach is loaded or not loaded in the FMS... excluding IAN obviously). For some weird reason you have to reselect the approach on the DEP/ARR page before G/S will arm again... blink.pngsig.gif

Share this post


Link to post
Share on other sites
I am having a ILS landing problem also but a little bit different. Still allow me to (mis)use this thread. LOL.gifI have since last thursday (that is before applying the SP!, so this has nothing to do with) problems with autoland on ILS.The approach is looking good. The Loc is captured and followed. The G/S is capatured and followed (so this is different from the orignal poster) but somehow the G/S doesn't always take me to the threshold. I end up too high and need to disengage AP and land manually (which is though if you are already high over treshold depending on runway length.This is not always happening. sequence of events1. Flight from EHAM to ENBR with STAR (no atc guidance) =====> came in too high2. Flight from EHAM to UMBB without STAR (atc vectoring) ======> came in too high3. Flight from EHRD to EHAM (without flightplan,ATC, manually tuning NAV radio's) ====> perfect4 Flight from EHRS to EHAM with STAR (no atc, but deviating from route) ===> perfect5. Flight from UMBB to UKLR (flightplan under fsx atc, no star) ====> perfect6. Flight from UKLR to LIMC (flightplan under fsx. atc, no star)===> came in too highThe approach page always shows proper navigation freq's and G/S on in green.What am i doing wrong?
Are you at ther correct approach speeds "every" time? If you are too fast you will overshoot the glideslope.vololiberista

Share this post


Link to post
Share on other sites

I am using the vref as stated on the approach ref page. Only on UMBB to UKLR i might have been a bit hot. (was flying without load at that time).Noticed another thread about this subject also (ngx floating on landing). Will check vref on every approach from now and stick to it (i tend to add 5 knts as safety margin but this might not be a good approach with the ngx)

Share this post


Link to post
Share on other sites
Hi,make sure you've selected the glidescope to ON in the APPROACH REF page. If you select a STAR for arrival, make sure you select the ILXX (where XX is the runway designator). I'm not sure if you select runway XX in the STAR page, the AP will descend on the glidescope. (=reply imnsims2). If you select ILSXX in the STAR page, the problem should be solved.
I must admit, I'm a little confused regarding the "GS on" in the FMC. I understood "GS on" was only for an IAN approach.I though with it off it was a conventional ILS approach. With it on, it's an IAN approach. Am I right or wrong?However, today with GS off in the FMC, the same thing happened to me, it reused to capture the glideslope, and glideslope not available appeared in the FMC.Perhaps someone with a handle on this can clarify.

Share this post


Link to post
Share on other sites

You don't need to be on approach speed to join the glideslope. The autopilot will happily drive down the approach at 250knots if you let it. If you are vectored onto final 20 miles out, you are not lilkely to be at REF+5 until your at or inside the FAF. If you're getting high on the glideslope, I wonder if you've really got it captured. What does the FMA say? Also, remember that the MCP doesn't tell you what mode you're in, that's what the FMA is for. Get us some screen shots and we can help out.

Share this post


Link to post
Share on other sites
You don't need to be on approach speed to join the glideslope. The autopilot will happily drive down the approach at 250knots if you let it. If you are vectored onto final 20 miles out, you are not lilkely to be at REF+5 until your at or inside the FAF.If you're getting high on the glideslope, I wonder if you've really got it captured. What does the FMA say? Also, remember that the MCP doesn't tell you what mode you're in, that's what the FMA is for. Get us some screen shots and we can help out.
Why would you want to "drive down the GS at 250kts!!" It's totally unrealistic and very very dangerous flying.vololiberista

Share this post


Link to post
Share on other sites
Why would you want to "drive down the GS at 250kts!!" It's totally unrealistic and very very dangerous flying.vololiberista
That's not something one does normally, but yes. I have done 250knots until 10 or 12nm out and then dropped the gear, etc. So, it's not totally unrealistic. In fact it was RW, so that's about realistic as it gets.The point was that you don't simply get high on the GS because you are fast. That isn't how the AFDS system works.

Share this post


Link to post
Share on other sites

You even drop your gear at too high a speed!!!!!!!!!!!You would only do that in an emergency flight manual permitting for something like an emergency depressurisation dive.vololiberista

Share this post


Link to post
Share on other sites

The GS mode will activate if the pointer is within a certain range of the middle line for at least 2 seconds. That is the way it works.

Share this post


Link to post
Share on other sites
You even drop your gear at too high a speed!!!!!!!!!!!You would only do that in an emergency flight manual permitting for something like an emergency depressurisation dive.vololiberista
I can see you feel strongly about this. What are you basing your thoughts on? Are you saying you can't extend the landing gear at 250 knots? What are you seeing that is unsafe?

Share this post


Link to post
Share on other sites
You would only do that in an emergency flight manual permitting for something like an emergency depressurisation dive.
Certainly not. You wanna go down fast during an emergency descent, so flight at VMO/MMO is performed for a reason (check your manuals). No margin for gear extension whatsoever here.sig.gif

Share this post


Link to post
Share on other sites
Certainly not. You wanna go down fast during an emergency descent, so flight at VMO/MMO is performed for a reason (check your manuals). No margin for gear extension whatsoever here.sig.gif
It depends on the a/c some are allowed to do it some not!!
I can see you feel strongly about this. What are you basing your thoughts on? Are you saying you can't extend the landing gear at 250 knots? What are you seeing that is unsafe?
I can see you feel strongly about this. What are you basing your thoughts on? Are you saying you can't extend the landing gear at 250 knots? What are you seeing that is unsafe?
Extending the landing gear at high speeds causes a huge amount of drag. Think about it!!For each a/c there exists different speed schedules properly placarded in the respective manuals. Extending gear at high speeds is a risky manouvre and can be done only in exceptional circumstances.vololiberista

Share this post


Link to post
Share on other sites
It depends on the a/c some are allowed to do it some not!!
Well yeah, but this is pretty much NG talk here...sig.gif

Share this post


Link to post
Share on other sites
It depends on the a/c some are allowed to do it some not!!Extending the landing gear at high speeds causes a huge amount of drag. Think about it!!For each a/c there exists different speed schedules properly placarded in the respective manuals. Extending gear at high speeds is a risky manouvre and can be done only in exceptional circumstances.vololiberista
Don't exceed limitations and recommendations and you're okay. I've done it plenty of times and it's not an emergency situation. I don't know what planes you've flown before (or if) but you can drop the gear at 250 on the 737.Oh, and extending the gear creates a huge amount of drag - that's the idea. Slow the plane down.

Share this post


Link to post
Share on other sites

Hmm, I'm a bit confused now as I got the impression that the NGX even starts diving if your are a bit high on the GS. Am I wrong?

Share this post


Link to post
Share on other sites

Did another flight yesterday evening from LIMC - EHAM. ILS 18C requested and got assigned.Since i was again very lightweighted my REF speed was 122 kts.I was aligned with localizer about 10 miles out. AP picked up correctly. I was low on G/S (diamond above middle).Altitude as per atc 2000 ft.When intercepting the G/S the FMC turned green and the plane started to descent. I kept my speed at 122. Although the diamond stayed correctly centered i noticed i was high through the use of HUGS. (the bullet was not pointing to threshold).Wind was something like 190/2 knots (so no real impact/problem). I took her off A/P and managed to get her in properly but what is going here?It seems i am the only one having this problem so logic dictates me i am doing something wrong. But what.I will see if i can capture a vid of this symptom and place it on youtube but have to figure out how to do that. Never done that before. Capturing a image is not a problem but i guess this will not properly show the symptom

Share this post


Link to post
Share on other sites
Hmm, I'm a bit confused now as I got the impression that the NGX even starts diving if your are a bit high on the GS. Am I wrong?
That was the point of my original post. The A/P will follow the G/S, regardless of speed. You won't simply "go high" because you're fast.

Share this post


Link to post
Share on other sites

Not capturing the glideslope is a bug and should be fixed in SP1b (I hope). There was a post about it a couple of weeks ago where one of the PMDG team (Ryan I think) advised they were working on a fix. The only reliable way to capture the glideslope at present is to select an ILS approach in the FMC then all works fine.Ian

Share this post


Link to post
Share on other sites
Not capturing the glideslope is a bug and should be fixed in SP1b (I hope). There was a post about it a couple of weeks ago where one of the PMDG team (Ryan I think) advised they were working on a fix. The only reliable way to capture the glideslope at present is to select an ILS approach in the FMC then all works fine.Ian
I'm afraid not sadly. Had two failed GS captures the other day in identical circumstances to all the other landings I've done. Aircraft simply flew through the GS and didn't descend. Roll on SP1b!

Share this post


Link to post
Share on other sites