GS problem

[Abrupto]

Hello!

I'm 10NM away from CYVR 26L in the default FSX 737-800 preparing to autoland. I have the VOR locked.Just in the moment the GS is captured and I'm beggining to descent on the GS without any apparent reason the throttle increase thrust and the plane all off a sudden climbs and goes up the GS. I need to do a missed approach.

What could be happening? I'm lost, please help,

Regards
Abrupto

[autocadplease]

I know that approach well. Can you give some more detail of how you fly the approach and what is your aircraft configuration when this happens (do you have your flap and gear down?).

[Abrupto]

I know that approach well. Can you give some more detail of how you fly the approach and what is your aircraft configuration when this happens (do you have your flap and gear down?).

Tank you for your help. So I'm flying runway heading 259º 10nm from touchdown at 160kt flaps 15 and gear down. The VOR is locked and APP is engaged. As I discribe as soon as the G/S is captured the throttle increase thrust and the plane all off a sudden climbs and goes up the GS.

I use the default FSX 737-800 with PM but the same problem happens with PMDG 737-800 . I think the problem is the PM configuration but where?

Regards
Abrupto

[yome]

Hello,

I think this is a well kown issue with fsX+PM

Check here: http://www.mycockpit.org/forums/showthread.php?t=10760
you will find some interesting informations.

I can't find a post where someone suggest to add +5 or +10kt when intecepting the glide, this create a pitch nose down moment and helps to intercept the glide.
Since I do this, it seems to work well.

regards

Guillaume.

[mmakela]

Hello, this can happen sometimes. I noticed with PM airbus type, that
I must have flaps 1 on, appr , ap1 and ap2 active when approaching gs
treshold (point where aircraft dives to ils path). I also noticed that I want to
put ILS navdata to MCDU radio page even if MCDU puts those automatically.
Without this I do not see correct RWY hdg in MCDU radio page. Those digits turns
bigger also when I enter those by myself?
I really do hope this can be fixed in the future.

[Abrupto]

Hello,

I think this is a well kown issue with fsX+PM

Check here: http://www.mycockpit.org/forums/showthread.php?t=10760
you will find some interesting informations.

I can't find a post where someone suggest to add +5 or +10kt when intecepting the glide, this create a pitch nose down moment and helps to intercept the glide.
Since I do this, it seems to work well.

regards

Guillaume.

Hello,

does someone know if there is already a solution for this?

Thank you,
Abrupto

[a340-th]

Seems not.

However, I find that an approach stabilized at an altitude below the ILS and a reasonable speed (around 160 - 170 kts for my airbii), as well as an intercept angle of < 30 degrees helps a lot to achieve proper GS capture in about 80 - 90 % of my cases. Not very realistic of course. I still watch the difference between the two indicators (GS and PM dot in the airbus case) like an eagle to be ready when it does not intercept the GS.

[mmakela]

This is a strange problem. For me with my A320/19 I have not seen any typical situation when I overshoot GS or not. It just happens sometimes with same approaches and RWYs.
What I noticed, that when I'm about to GS dive, this happens:
First HDG loc captures. This is allways ok. soon the magenta diamond starts to move down. If the magenta circle (yoyo) does
not follow soon, I'll get missed GS dive. This yoyo allways comes down, but if the diamond has passed horizontal line much before,
the aircraft is too high during final, so I miss the RWY.
I believe this has to do with different informations of altitudes. FS thinks something and PM is thinking something. What about weather settings , fsuipc settings , 3party program settings?

[a340-th]

Yep, thats the way it goes. Yesterday the magenta yoyo did not catch up with the diamond in 3 approaches out of 4.

The situation cannot be replicated, sometime it works, sometime it does not at the same airport with the same approach.....

I usually switch to a LOC approach and control the V/S manually until I switch off the AP.

[Hans Krohn]

Hi guys,

I have encountered the same problem many times, and when it happened it drove me nuts!

The solution that seems to work for me is to intercept the GS at the the speed the CDU -> Index ->Approach Page gives me for flaps setting 25 or 30. That is usually way below the 160 0r 170 ktn mentioned earlier in this thread, but more in the 120 to 130 kts range. This seems to give the PM software more time to do it's thing. As a result my descents work very well lately (all the way down to touchdown if autoland is engaged).

Hope this helps!

Regards, Hans


My cockpit project:
www.hanskrohn.com

[a340-th]

Hallo Hans

how for out do you need to reduce speed ?

Of course with flap setting 2 at 20 odd NM we airbii pilots can also do slower speeds <G>

[Hans Krohn]

Hi Erhard,

I usually reduce speed when the vertical diamond starts to move down towards center (i.e. right before I intersect the GS).

Regards, Hans

[a340-th]

Thanks Hans,

I'll try this too.