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aircraft goes upwards fastwhen using 'APP' button

Posted:
Fri Apr 10, 2009 4:55 pm
by satz
hi all
recently changed to FS2004 after years of 2002.
I've always used the ILS approach to airports (where available). Following the voice prompts to make changes to direction and altitude.
And then I always select the 'APP' button after getting the message about "....set heading to xxx degrees and altitude to yyyy until you achieve the localiser...". This has always correctly guided me to line up with the runway.
However in FS2004, following exactly the same steps, causes big problems in some airports. eg LAX and Geneva (Switzerland):
After selecting 'APP', the plane starts climbing steeply (up to 10000 feet or more!), remembering this is fairly close to the airport. Sometimes it stalls, etc...
Is this a problem with 2004? or do I need to change my approach procedures from what I was doing in 2002?
please let meknow
thank you
Satz
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Fri Apr 10, 2009 5:13 pm
by dave3cu
I don't recall any problems in this regard, nor any difference from FS2002 to 2004.
Do you have the AP-Hdg and Alt hold activated and flying straight and level below the glide slope before activating APP?
Dave
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Fri Apr 10, 2009 8:24 pm
by DaveSims
I have also had a lot of problems with the approach hold finding the glideslope in 2004, not sure why. Its made me hand fly a lot more, which isn't all bad.
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Fri Apr 10, 2009 11:31 pm
by Nav
Satz, you may still be above the glideslope when you press 'APP'; alternatively, you may be switching off the 'HDG' and 'ALT' buttons as you press 'APP.'
Correct procedure is to make sure that you are below the glideslope before you engage 'APP' - and also leave 'HDG' and 'ALT' on until the A/P switches them off.
See if this helps (from FAQs):-
http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?board=COF;action=display;num=1111322151
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 12:51 am
by -Crossfire-
It might be the plane you are in. I've downloaded some freeware addons where the AP simply won't capture the ILS properlly. I've had no problem with the default planes though.
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 11:29 am
by HoratioWondersocks
Have you made sure your NAV/GPS switch is on NAV.
Andy
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 12:48 pm
by JerryH
Satz, I've had similar problems with FS2004 after using FS2002 for many years. I think the problem may be only with some aircraft or some airports.
My suggestion would be to capture the localiser with NAV rather than APP. Then, when the glideslope comes alive, click on APP to finish your approach. The only problem with this (for me) is forgetting to switch on the APP button. If my copilot were awake life would be a lot simpler.
Let us know when you solve your problem.
Regards,
JerryH
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 4:18 pm
by satz
it happens both with Addon and inbuilt aircraft.
I'll pick APP just at the time the ATC says 'descend to 2000 until intercept localiser' or something like that.
I leave the IAS and ALT buttons on until they are turned off automatically. This used to work perfectly in FS2002 but in 2004 (some airports) sends the aircraft upwards steeply!
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 5:04 pm
by JerryH
I understand what you mean when you say it worked perfectly in FS2002 but not in FS2004. I agree, but don't know why there is a difference.
For some reason, with some aircraft or airports, if you select APP too early it will switch off the ALT hold prematurely. If you then switch ALT back on, the APP may simply ignore the glideslope. That's why I often capture the localiser with NAV and turn on the APP later.
Try it and see if it helps.
Regards,
JerryH
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sat Apr 11, 2009 5:34 pm
by Zfly2sky
[left]I have learned that there are many variables i.e. airport Navs, aircraft settings and just how the settings are set.
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sun Apr 12, 2009 5:56 am
by PhilDawson
A better procedure, is to first intercept the glideslope by hand, once you are established fairly well in the descent and lined up with the runway then use the APP switch.
Remember that it's an Approach HOLD switch, and will cause erratic ap control if you're not established or very close to being.
Re: aircraft goes upwards fast when using 'APP' button

Posted:
Sun Apr 12, 2009 6:14 am
by Fozzer
Well...I must admit...I've never had any problems with any of my General Aviation, Piston Prop/Turbo Prop aircraft at any airfield in FS2004...

...!
I follow the normal procedures for "Radio Navigation", and it all works out fine...

...!
I just make sure that I am on the correct glide path, at the correct altitude, for the correct runway heading, (via "ATIS"), and it all goes very smoothly...
...no one dies, or is forced to use their "Sick Bag"....

...

...!
Paul...G-BPLF...FS 2004...FS Navigator....and a lovely Bendix-King Radio Stack... 8-)...!
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sun Apr 12, 2009 12:30 pm
by DaveSims
[quote][left]I have learned that there are many variables i.e. airport Navs, aircraft settings and just how the settings are set.
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sun Apr 12, 2009 3:48 pm
by Fr. Bill
[quote]
I'll pick APP just at the time the ATC says 'descend to 2000 until intercept localiser'
Re: aircraft goes upwards fastwhen using 'APP' button

Posted:
Sun Apr 12, 2009 11:07 pm
by satz
hi all
I think I'm under the glideslope when I select APP...I'm guessing that's why the ac tries to climb steeply to intercept the glideslope.
However I'll try what Fr Bill suggests above, and get to the the specified altitude before selecting APP.
cheers
Satz