ILS Approaches

[EHM-1969 Michael]

Hi there,

I would like to learn how to do these?

Could anyone fill me in or have some sort of tutorial?

Thank and also how can I calculate when to descend and at what rate?? Thanks

[EHM-1883 Matt]

It's pretty simple. First you have to find out what runway you're landing on. Usually ATC will tell you, but you need to find out first to go to the next step. Then go into FSPlanner, and If you click on the airport, an information box will pop up. Find the runway, and then scroll across, and there should be something unde the column ILS Freq. Write down that frequency, and then make it active on the NAV1 radio. You could now do the ILS manually or Automatically.

To do it Automatically, once you're close to the runway, flick on the autopilot master switch, then click the button that says APP. The ILS approach will then be done for you.

To do it manually, the VOR indicator will tell you where to go. If the vertical needle is to the left, you go to the left. If it's to the right, you go to the right. If the Horizontal needle is down, you need to go down, if it is up, you need to go up. Pretty simple.

The final thing is when in an ILS approach, you might not know how far you are from the runway. There are three buttons that tell you this. They're usually above the VOR indicator. A blue, orange and white one. When the blue one flashes, that means you are at the begining of the ILS. When the Orange one flashes, it means your half-way through the ILS. When the white one flashes, you're at the end. I usually take the AP off after the whit one flashes, as by the time the white one flashes, you should be in line with the runway, and ready to do a landing.

Hope this helps. If you need further help, don't hesitate to ask, and welcome to the EuroHarmony VA!

[EHM-1969 Michael]

Ah Thanks mate - I'll try that tommorow.

Do you know how to calculate when to descend and at what rate??

Thanks;)

[EHM-0654 Murray]

Not that I can remember the specifics of it, but there's a fairly simple "allow X nautical miles for every Y thousand feet of altitude, based on a cruise speed of Z".

EDIT: Found it... For a 737-200 (so we're looking at a descent speed around 280KIAS until FL100, 250KIAS thereafter) you can get by with "3 to 1"; 3nm for every 1,000 feet of alt. And just remember to add a little for safety thereafter.

Hope that helps you mate.

[EHM-1883 Matt]

No problem!

If ATC is online, they will usually line you up with the runway, and then once you're lined up, they will ask you whether you're established on the ILS localizer. That basically means can you do an ILS approach yet, and the way I know is when the VOR indicator starts moving up or down, or the APP button works, and takes over the aircraft. if there is no ATC online, I usually fly far away from the airport, and then fly striaght towards the runway, and then wait for the APP button to work, or the VOR to start moving. This has something to do with the descent. The way you know when to start descending is when the VOR indicator's horizontal needle goes down, and you must follow it. The clever thing about that needle is it will keep you in line, like lets say I'm flying towards the ILS at 4000ft. As soon as I am "established" on the ILS, the VOR might think that I shouldn't be at 4000, and I should be at 2000. The needle will then point down, and I will go down. As soon as I get to 2000, the needle will then go back into the middle, telling me to hold at this altitude. The way you know what rate to descend at is seeing how far the Horizontal needle goes down. If it drops a bit, you will know you only have to go down a bit, before it levels off. If it's half way down, you will know to descend quickly, but not urgently, and if it's all the way at the bottom, you'd have to drop quickly!

Another big factor is common sense really. You don't always need a VOR indicator to tell you you're too high or too low, such as if the runway was very close, and you were at 3000ft, I think something would tell you that you're too high!

The only thing you've got to look out for is the VOR indicator is a very sensitive instrument, and might tell you to do a dramatic drop just so you can go down 500ft, so don't panick if the needles are over-reacting, just take it slowly, and concentrate. It always works for me, but if you're using autopilot, you don't really need to know any of that, because it does it all for you!


The final thing I have to say in this long boring message is that practise makes perfect. I personally have my own ways of landing, and they usually work, and on some landings I disagree with what the VOR indicator is telling me, such as I was in terrible crosswind the other day, and I decided to go low, so it would be easier.

Hope everything goes well. I have described everything to the best of my knowledge, so hopefully it'll work fine, but if there's any problems, just tell anyone and I'm sure they'll do their best to help!;D

[EHM-0654 Murray]

Found a really interesting PDF in my searching for the "3 to 1" guidance.

http://www.ggpsystems.co.uk/downloads/whiz_wheel_explanation.pdf

EDIT: In attempting to print this here at work, I've noticed that the PDF was damaged. Is fixed now.

[EHM-1651 Christian]

And you will find all the info you need for the actual app conducted in the ILS plate.

[EHM-2089 Vincent]

Good Info, I did find the above ILS approach quite useful, I have been doing something like that only, but was not sure of the time I should release the AP to OFF. So now I will look for the Inner Marker and quickly turn this off.

Approach plates are quite cryptic, but I managed to get one page on Vatsim which did some good explanation on the Approach plates, and after that I am like a little more comfortable when I look at the approach plates. However for me too there seems a lot to learn.

ILS is a wonderful tool, especially when you are low on visibility. I plan my descent and my approach to the ILS cone from very far and hence normally line up in line with the runway very early. I lock my ILS frequency and click on App button which does the final lining up to do a straight landing. The only thing needed to control is that when you hit the green cone on the GPS window, you speed should be very close to the required landing speed + 10 kts max. That ensures that the plane does not start rocking around too much in making the final landing adjustments.

Lastly its a good idea to put the guides on. In the Aircraft Menu, Visual Flight Path, (click on Enable Visual flight path after the ILS freq is entered into the Radio Panel)   ,lock that to the Nav1 Radio and you will get rectangles coming up showing you exactly whether you are in line or not. Try doing it for a while and then you can use your stick / keyboard for doing the landing, without locking to ILS and APP, thats what I love doing now. I practiced enough with ILS locked, now with the NAV guides, I managed to keep my plane in the Cone. Ofcourse I try that on my favourite planes only and keep big birds above 737 only on ILS.

For all this I make it a point to make sure that I have the NavLog printed / written down from the Flight Manager thats built in into FS 2004 itself. I make sure that I have a notepad where the destination frequencies are copied and kept as well.

Hope this info helps and thats the way I fly :> and make my flying more interesting as well. Would love to hear comments.

[EHM-1671 Ben]

I have been using Murray's 3 to 1 rule for about a year as a general rule of when to descend and how fast to descend from cruise altitude - I like to add about 10 miles on to the 3 to 1 total as a safety precaution

As for ILS descent rates, if you've intercepted the frequency and are tracking the runway I like to descend at about -800 feet per minute. If I'm to high I may descend at a rate as high as -1000fpm, and if I'm too low I'll descend at just -200fpm - sometimes I may even level off - and wait for the glideslope to 'come' to me.

Hope that helps, and happy flying