Simviation Forum - ILS and ATC issues

Oct 8^th, 2009 at 4:32pm

krusbullen Offline
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Hi,
I have noticed a irritating problem. When i have done a flight and started my ILS approach, the ATC gives me strange directions and altitudes. Sometimes it works and sometimes i miss the runway. Sometimes to far to left or right and sometimes way to high.

I recently installed the aerosoft mega airport Arlanda and noticed this. I thougt it was because the new uppdatet add on included the new runway but i did everything like i always do. What is the problem?

Another fenomen that i noticed is that if i do a long haul flight i don´t want to sit at the computer because the only thing you do is to change frequence and ask for flight following. If i do something else and miss it for like ten minutes they say radar service terminated. Does this mean that i don´t get ATC heading and altitude instructions when i start my approach? Because sometimes i don´t. I hope you guys and girls can straight this out Wink

.

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Reply #1 - Oct 8^th, 2009 at 5:23pm

ApplePie Offline
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North Carolina, USA

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What I do for ATC frequency changes is acknowledge frequency change, but don't change frequency.

Then when I'm about 150-100nm from the destination I tune back in and voila! I'm still being handled by ATC.

MY SPECS= 5' 11" Slightly less than healthy male, 160 lbs., Brown eyes........Oh...you were wondering about my computers specs.....

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Reply #2 - Oct 8^th, 2009 at 5:51pm

beaky Offline
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ATC in the sim is pretty goofy in general, but sometimes in RL one will get a roundabout sort of route from them as you let down to pick up the localizer. Not much you can do about it in the sim except ignore them or declare a missed approach. The way I cope with it, although I rarely do that kind of flying in the sim, is to expect the most idiotic routing imaginable, keep my speed down, and make my descents fairly rapid when possible.

As for getting dropped when you aren't answering the radio calls: Yes, "radar service terminated" means you are on your own. I've never allowed that to happen when flying under IFR in the sim, but I suppose that's how it's handled by the program. In RL, you'd have a lot of explaining to do later! Grin

But whether you are IFR or VFR, in the sim, if you want vectors/altitudes or flight following after getting dropped, just call the nearest ATC facility again. I think (not sure) that if you try to do this after getting dropped while IFR, you will have to "create an IFR flight plan" again, but all you'd need to do is re-load the old plan but not select "move the aircraft to the departure airport, etc". Then you should be able to get a new clearance from ATC to proceed.

OR... you could just blunder along under radio silence and make contact with the tower at your destination (if there is a tower). But if the airport is under IFR at that moment, you'll need to have an IFR plan and get a clearance first.

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Reply #3 - Oct 8^th, 2009 at 5:56pm

DaveSims Offline
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Clear Lake, Iowa

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My solution to the useless vectoring ATC gives in sim is to select an approach with an intial point (look up the approaches on the GPS). Then ATC will clear you direct to the initial fix without vectors and clear you for the approach.

Dave

www.flymcw.com

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Reply #4 - Oct 8^th, 2009 at 6:05pm

krusbullen Offline
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Thanks for good replys. When it comes to de navigation. The whiteline that should point at my direction is pointing a few degrees right to the centerline. Can it be why the approach is getting wrong?

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Reply #5 - Oct 9^th, 2009 at 10:36pm

beaky Offline
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krusbullen wrote on Oct 8^th, 2009 at 6:05pm:

Thanks for good replys. When it comes to de navigation. The whiteline that should point at my direction is pointing a few degrees right to the centerline. Can it be why the approach is getting wrong?

Yes... if I assume correctly that you are talking about the vertical needle on the ILS receiver. You need to get that centered as soon as you intercept the localizer, before you start descending on the ILS glideslope (represented by the horizontal needle).
Part of the problem may also be that ATC might give you "vectors to final", leaving you on a heading that is not quite right as you begin your approach. It's best to start centering that needle as soon as it "comes alive" regardless of what ATC tells you.
Also: even in RL, ILS localizer beams are not always aligned precisely with the runway, in order to ensure that arriving flights remain clear of obstacles until the "minimums" are reached- that is, the lowest altitude you can go without quite seeing the runway clearly (assuming conditions are IMC). That's just the way it is- sometimes runways point at mountains, towers, etc... not a big deal when you are making a visual approach, but rather dangerous when you are descending in IMC. There are other reasons why localizer antennae wind up off-center: changes to the airport infrastructure, etc. The idea is that, when you reach the minimum safe altitude, you should be able to see the runway and be able to turn slightly as needed to land on-center. This is why the autopilot should be turned off when you see the runway lights, if not a little sooner. Otherwise, it will continue to track the localizer, which may be off-center. There are many approaches that track right down the runway, allowing more use of the autopilot and even much lower minimums, but not all of them, and in RL, crews manage to cope with this pretty well.
Unfortunately, I don't think FS9 provides this information for each airport, so it's a matter of expecting it.
At any rate, just make sure you begin the final descent on-center as far as the localizer is concerned.

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Reply #6 - Oct 13^th, 2009 at 2:51pm

krusbullen Offline
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Many thanks for the good answer. Thats why some airport often get wrong and some always perfect. Hmm you learn something new every day.. Wink

beaky wrote on Oct 9^th, 2009 at 10:36pm:

krusbullen wrote on Oct 8^th, 2009 at 6:05pm:

Thanks for good replys. When it comes to de navigation. The whiteline that should point at my direction is pointing a few degrees right to the centerline. Can it be why the approach is getting wrong?

Yes... if I assume correctly that you are talking about the vertical needle on the ILS receiver. You need to get that centered as soon as you intercept the localizer, before you start descending on the ILS glideslope (represented by the horizontal needle).
Part of the problem may also be that ATC might give you "vectors to final", leaving you on a heading that is not quite right as you begin your approach. It's best to start centering that needle as soon as it "comes alive" regardless of what ATC tells you.
Also: even in RL, ILS localizer beams are not always aligned precisely with the runway, in order to ensure that arriving flights remain clear of obstacles until the "minimums" are reached- that is, the lowest altitude you can go without quite seeing the runway clearly (assuming conditions are IMC). That's just the way it is- sometimes runways point at mountains, towers, etc... not a big deal when you are making a visual approach, but rather dangerous when you are descending in IMC. There are other reasons why localizer antennae wind up off-center: changes to the airport infrastructure, etc. The idea is that, when you reach the minimum safe altitude, you should be able to see the runway and be able to turn slightly as needed to land on-center. This is why the autopilot should be turned off when you see the runway lights, if not a little sooner. Otherwise, it will continue to track the localizer, which may be off-center. There are many approaches that track right down the runway, allowing more use of the autopilot and even much lower minimums, but not all of them, and in RL, crews manage to cope with this pretty well.
Unfortunately, I don't think FS9 provides this information for each airport, so it's a matter of expecting it.
At any rate, just make sure you begin the final descent on-center as far as the localizer is concerned.

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Reply #7 - Oct 13^th, 2009 at 11:59pm

Nav Offline
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krusbullen, most likely your problems mainly arise from two basic things - not starting the landing process early enough, and flying too fast.

First of all, there's the 'Rule of Three' - at any sort of normal descent rate, virtually all aircraft descend one mile for every three miles of forward progress. So if you're in an airliner at 33,000 feet, for instance, you should start your descent no less than 100 miles out.

Secondly, in most parts of the world, all aircraft are restricted to a maximum airspeed of 250 knots below 10,000 feet.

FS9 ATC is designed on the assumption that you are complying with those rules (and also following your filed IFR flightplan) and will therefore give you vectors and heights based on the assumption that you are starting off (from up to 30 miles out, when you first contact ATC for landing instructions) in the right place, and also low enough and slow enough to manouevre in plenty of time to intercept the glidepath and glideslope at the proper point. If, at fifteen miles out, you're off course, 5,000 feet too high, and still travelling at 400 knots, there's nothing ATC can do about it!

It's a good idea, as you start your letdown, to set the Indicated Airspeed to 240 knots. In the thinner air higher up, your true speed will obviously be much higher than this, but once you get down lower you'll be down to the proper speed. Use the default rate of descent or alternatively set it at say 2,500 feet per minute or so.

About the ILS not lining up immediately, remember that it's a flight simulator, not a railway one! The air is a fluid medium - the Sim will take it's time getting into line, but it will eventually get there! In any case, if there is any crosswind, the Sim will do the 'crabbing' for you, point the nose a few degrees upwind to keep you in line with the runway, so the Indicator may show you a touch off-line all the way down.

About offset ILS beams at some airports, as mentioned by rottydaddy, these are rare - but in any case you can forewarn yourself by calling up the Map, centring it on your destination airport, and enlarging the view. The approach path will be clearly shown as a green 'feather' and any offset will be clearly visible.

Finally, maybe see if this helps?

http://205.252.250.26/cgi-bin/yabb2/YaBB.pl?board=COF;action=display;num=1111322...

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