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help needed on ILS

Pro Member First Officer
abmukh80 First Officer

Hi,

I needed some help on ILS. I have gone through the entire theory but everybody fails to explain what exactly needs to be done during the approach. I need some step by step answers.

1.After the controller advises me to switch to airport approach, what should be done?

2. How do I need to tune my radios manually, if required?

3. When I switch to NAV mode what is the ADF about and how do I intercept the ILS glidescope when I'm advised to switch to airport tower?

4. How to use the glidescope to a smooth landing even when visiblity is bad?

Well let me tel you guys, despite not knowing about ILS I'm technically quite sound about FS. So dont hesitate to get into instruments, I'm good at those. Please help me regarding this. I'm very close to learning it but without practical help, I'm unable to do it.

Cheers

22 Responses

Pro Member Trainee
paul2007 Trainee

Do you have FSX, if so one of the passenger jet missions deals with ILS landings it'll be the quickest way to learn what you don't already know, unless you can talk to someone whilst your actually flying.

Pro Member Chief Captain
RadarMan Chief Captain
Pro Member Chief Captain
CRJCapt Chief Captain

This is a great reference also: ➡ http://www.navfltsm.addr.com/index.htm

Pro Member First Officer
abmukh80 First Officer

thanks guys for all the help. the links were just amazing and had the exact things i wanted to know.
Two questions:

1. After we enter the runway heading in the course, what should I do with the heading indicator? I mean at this position should the heading hold switch be on or off? and what difference will it make?

2. On the radio stacks, after I switch on the 'nav' button do I also have to switch on the 'both' button?

Cheers

Pro Member Trainee
paul2007 Trainee

what aircraft r u in they do differ?

but basically once you set the rw course you should be heading to intercept the ILS signal as this happens hit the NAV button, then you watch the "caret" on the HLS till it reaches the "horizon" then you hit APPR button and your aircraft will follow the GS to the threshold of the rw.

hitting the NAV button turns off the HDG and hitting the APPR button turns of the NAV and ALT button if u r using them.

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

abmukh80 wrote:

thanks guys for all the help. the links were just amazing and had the exact things i wanted to know.
Two questions:

1. After we enter the runway heading in the course, what should I do with the heading indicator? I mean at this position should the heading hold switch be on or off? and what difference will it make?

2. On the radio stacks, after I switch on the 'nav' button do I also have to switch on the 'both' button?

Cheers

1. You don't have to do anything with the heading indicator. The heading hold button should be disengaged so you can engage the APP / APR button.

2. 'Both' refers to the COMs channels so you can multi-task...listen to ATIS / talk to approach for example. Irrelevant in the case of the sim for an ILS approach.

Pro Member First Officer
abmukh80 First Officer

Hi guys,

With the help in the links I was able to make an ILS approach and a landing. But 1 thing still surprises me is when I hit the approach button around 10-12 m from the runway, the aircrafts horizontal position is fine, but it only starts losing altitude as close as 3-4 m which is a bit dangerous. You are in some sort of uncertainty especially in poor visibility.

What I wanted to know was have I committed some mistakes somewhere or this is a normal feature of the ILS?

Waiting for ur reply.

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

abmukh80 wrote:

Hi guys,

With the help in the links I was able to make an ILS approach and a landing. But 1 thing still surprises me is when I hit the approach button around 10-12 m from the runway, the aircrafts horizontal position is fine, but it only starts losing altitude as close as 3-4 m which is a bit dangerous. You are in some sort of uncertainty especially in poor visibility.

What I wanted to know was have I committed some mistakes somewhere or this is a normal feature of the ILS?

Waiting for ur reply.

Maybe too fast on approach - what speed are you doing?

Pro Member First Officer
abmukh80 First Officer

speed was perfect around 180knots as asked and i was at 12m from the airport at 2500. Approach to kingsford smith intl, sydney.

One more thing I would like to know is how do i differentiate between aairports having cat-1 and cat-2 ILS?

Waiting for your reply

Pro Member Chief Captain
Jonathan (99jolegg) Chief Captain

In the sim, I'm not 100% sure - it doesn't tell you on the map I don't think. It'll definitely tell you on the approach chart though there are a few free sites you can download them from, depending on the country you are in.

Pro Member Trainee
paul2007 Trainee

abmukh80 wrote:

speed was perfect around 180knots as asked and i was at 12m from the airport at 2500. Approach to kingsford smith intl, sydney.

One more thing I would like to know is how do i differentiate between aairports having cat-1 and cat-2 ILS?

Waiting for your reply

at that distance you want to start to slow to 140kts so your doing 140kts as you start decent with full flaps and gear down

Pro Member First Officer
abmukh80 First Officer

as it is at 170kias the nose is 7-8 degrees up. If i further reduce speed with full flaps and gear down nose will further go up, and aircraft will stall, wont it?

correct me if i'm wrong. what i dont understand is why the descent is not gradual in ILS? Say the final descent from 2500 to 500 which starts at around 7-8 miles out. Why does the descent start only at 4 miles out?

i still think i'm goin wrong somewhere. its nearly done but the nose needs to be done so that i could see the runway from cockpit.

Pro Member First Officer
Jim (jellrod) First Officer

No, the aircraft needs to fly that angle of attack (nose up) for proper landing attitude and speed. If you cant see the runway, go to the virtual cockpit, and adjust your seat up so you can (like you do in the real world).

Pro Member First Officer
abmukh80 First Officer

how do you adjust the seat in FSX. Sorry bro no clue about it. Obviously i can go to the virtual cockpit mode.

Pro Member Chief Captain
RadarMan Chief Captain

Shift+Enter.

Radar

Pro Member First Officer
Jim (jellrod) First Officer

As RADARMAN says it is SHIFT + ENTER, but it only works in Virtual Cockpit. You can also use the + and - keys to zoom in and out in the VC to see the instruments better as well. SOme of the instruments are active in VC, like the Autopilit switches, NAV switches etc. Once I set up the flight plan on the ground, I switch to VC and fly the flight from there - more realistic, you can lookaround the cockpit and watcht he runway on your downwind leg etc.....

Pro Member First Officer
abmukh80 First Officer

yeah i tried it works fine but why to do it in the vc mode? i mean i can see everythin anyways from vc.

Any other option from the cockpit itself?

Pro Member First Officer
abmukh80 First Officer

Hi guys,

Thanks a ton for all the help regarding ILS approaches. I must admit I'm in a much better position than what I was a few wks back! I still hv 2 problems in the final stages during an ILS They are:

1. At around 16 m out after I tune my NAV1 and select the course and hit the app button-obviously the heading hold switch is disengaged by ap. Surprisingly in some aircrafts the alt hold switch is not disengaged. I hv to manually control the altitude till DH! On the aircrafts which disengages the alt hold on hitting app switch I find myself too high even at DH.

2. When the weather is set to rough-very rough with rain and severe turbulence I find myself slightly off track to the runway. I mean laterally. The problem is by the time I realise this in low visibility I'm either at the DH or just over the runway which is quite late to correct things.

I'm trying all this in a 747 making the final app at around 165-170 knots as written in all the forums. Since this is a common problem I'm facing I thought I might be wrong somewhere. Please hep.

Cheers

Pro Member First Officer
Jim (jellrod) First Officer

When you say you are 16 miles out, does this happen at every airport you fly inot? it shouldn't. What airport are you landing at that you have this problem? If you have the proper frequenct of the ILS set in NAV1, the ILS should privide heading and altitude corrections all the way down to the deck. Don't get nervous if it doesnt kick in as you intercept the GS. Watch the bug on the HSI.

Now if you are drifting, it could be that the correct course is not set. (If you look at the runway on the map, look for the green looking arrow, and run your mouse over it, it will give you the ILS info. The Runway number is NOT always the true heading number). For ex, at Nairobi, the ILS is Runway 6, but you need to set 055 in the course bug to track straight and true to the runway.

And if the weather is rough, the aircraft will "crab" or fly with its nose into the wind so it does not drift off course. When you get over the numbers, disengage (you should have done that when you came over the inner marker) and manually fly it onto the deck.

Pro Member First Officer
abmukh80 First Officer

As far as the correct course and NAV is concerned I'm entering right value. But the alt hold should disengage on hitting the app switch! Which is not happening.

What should be my approx height at the outer marker of ILS? Lets assume the airport is at 0 elevation

Pro Member Chief Captain
CRJCapt Chief Captain

Glideslope
The height of the Glideslope is approximately 1500 ft. AGL at 5 statue miles from the runway.

The altitude hold button[ALT] will remain engaged with the approach mode[APR] selected and will disengage upon Glideslope intercept.

The course indication of the HSI needle has no effect on tracking the Localizer signal. The reason for setting the inbound course of the ILS is so that course deviations are shown correctly. If the setting is off by 10 degrees, it won't have any effect.

Radio panel
The buttons on the top of the radio panel are audio buttons that have no effect on the function of the NAV radios. They are used to positively identify that you are receiving the correct signal by matching the Morse code identifier you hear with the the ILS approach chart. The COM 1 and COM 2 and both simply allow you to hear the radios.

ILS categories
There is only one type of ILS in Flight Simulator but in the real world there are five. The difference between them is how low you can descend without seeing the runway[DH] and minimum visibility required measured in statue miles or feet. These are regulatory rules.

CAT I ILS-Normal ILS
DH no lower than 200 ft. AGL and visibility of no less than 1/2 mile. Visibility can be 1800 ft. with correct approach lighting installed.

CAT II ILS
DH no lower than 100 ft. and visibility no less than 1200 ft. Require special crew certification, special maintenance inspections and certification for aircraft and is only certified at certain runways.

There are also CAT IIIa, CAT IIIb and CAT IIIc.
http://en.wikipedia.org/wiki/Instrument_Landing_System

I recommend learning the ILS with the Cessna 172. The 747, or other heavy jets, will lead to much frustration.



Last edited by CRJCapt on Wed Aug 01, 2007 2:06 pm, edited 1 time in total
Pro Member First Officer
abmukh80 First Officer

Thanks a ton for all the inputs. I was under the impression that the alt hold is automatically turned off even before intercepting the Glidescope. Silly thinking though!!!!

I'll try it out again now.

Cheers

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