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ILS question/problem..

PostPosted: Mon Mar 05, 2007 12:11 pm
by fulanito_uk
hi guys...
ok the question/problem is when landing using ILS every thing is perfect however on finals (very final) it seems the aircraft is lined up not with the center of the runway but slightly to one side (still tarmac but much far right)... i have to disconect A/P and land manually is this normal???

or is it bug? THANKS!!!

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 1:17 pm
by ashaman
Sometimes the AFCAD of a given airport can be slightly faulty. It had happened countless times to me too to follow a ILS that did not bring me on the center of the runway. It's hardly a rare thing.

Solution: either search on the net a corrected AFCAD file for the given airport or correct the displacing of the navaids yourself with the AFCAD program.

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 1:45 pm
by Sir_Crashalot
As far as I know ILS is not an Autoland function. You always land manually even when using ILS. It's just a guidance system to the runway.

Crash ;)

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 3:05 pm
by jimcooper1
Some ILS are deliberately NOT aligned with the centreline to avoid obstructions or controlled airspace.

Eg. The centreline at Kinloss (EGQK) is on a bearing of 260*.  This will take you directly over Lossiemouth airfield (EGQS) approx 8 miles away.
So the ILS ay Kinloss is alligned with 258* so that on approach Lossiemouth is avoided.  Autopilot is disengaged after the middle marker and the aircraft has to be turned on to the final heading.

Jim

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 3:10 pm
by TSC.
Also remember that the glideslope antenna array is situated to one side of the runway near the touchdown zone - so if you leave your AP on long enough, where will it go?

Cheers,

TSC.

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 4:14 pm
by Jakemaster
As far as I know ILS is not an Autoland function. You always land manually even when using ILS. It's just a guidance system to the runway.

Crash ;)


Yes, ILS isn't autoland.  When you fly ILS, even with autopilot, you turn off the autopilot prior to touchdown and do it yourself.

Re: ILS question/problem..

PostPosted: Mon Mar 05, 2007 6:15 pm
by Nav
fulanito, the ILS system is probably allowing for wind! You very seldom get completely windless conditions, even in FS. If you press 'Shift-Z' a couple of times you'll get the wind direction and strength shown in red at the top of the screen (go on pressing 'Shift-Z' to clear).

And yes, if you let the ILS system carry out the final approach and landing you'll only achieve a very heavy landing indeed. Full explanation (including 'crabbing' to allow for wind) on here:-

http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?board=COF;action=display;num=1111322151

Also one on full manual crosswind landings:-

http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?board=COF;action=display;num=1129643666

Re: ILS question/problem..

PostPosted: Tue Mar 06, 2007 5:51 am
by fulanito_uk
Thanks all your comments... i have started manual landing using ILS more as a guide/aid than an auto land. and have had a few bumpy landing but am getting better..

Re: ILS question/problem..

PostPosted: Tue Mar 06, 2007 11:06 am
by beaky
Thanks all your comments... I have started manual landing using ILS more as a guide/aid than an auto land. and have had a few bumpy landing but am getting better..


Good on ya. On most ILS approaches, RL pilots disconnect the AP at or shortly after the point where they intercept the localizer. It's not that hard with a little practice, even descending properly. I find it devilish in jets because of the way they respond to power changes compared to prop planes, but even I can hand-fly an ILS in a jet airliner reasonably well.
Remember that in RL, unless set up for Category IIIC approaches (no visibility or cloud-height minimum) , most ILS systems are not 100% aligned with the runway for various reasons... pilots are expected to have the runway in sight at a particular minimum altitude AGL and make adjustments accordingly.

Re: ILS question/problem..

PostPosted: Tue Mar 06, 2007 11:10 am
by beaky
Thanks all your comments... i have started manual landing using ILS more as a guide/aid than an auto land. and have had a few bumpy landing but am getting better..



Thanks all your comments... I have started manual landing using ILS more as a guide/aid than an auto land. and have had a few bumpy landing but am getting better..


Good on ya. On most ILS approaches, RL pilots disconnect the AP at or shortly after the point where they intercept the localizer. It's not that hard with a little practice, even descending properly. I find it devilish in jets because of the way they respond to power changes compared to prop planes, but even I can hand-fly an ILS in a jet airliner reasonably well.
Remember that in RL, unless set up for Category IIIC approaches (no visibility or cloud-height minimum) , most ILS systems are not 100% aligned with the runway for various reasons... pilots are expected to have the runway in sight at a particular minimum altitude AGL and make adjustments accordingly. If they don't have the runway in sight at that "decision height", they should go around and follow the missed-approach procedure.

I'd advise finding some approach plates, either online or at a pilot shop (they throw away the outdated ones, and are usually happy to give them away to flight simmers)- studying the profile of an instrument approach will give you a better idea of how to set up for an ILS approach.
And it's a fun challenge, especially executing a missed approach!