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ILS approaches (please help before I go nuts)

fallenphoenix1986

fallenphoenix1986

SOH-CM-2022
Usually I'm to be found around carriers in various fast jets doing everything manually however over the last few days I've been flying heavy iron and am trying to grasp ILS approaches. Having watched a few tutorials on youtube I think I get how I'm supposed to set up the autopilot and radios however when I cross the glideslope in the default 737 rather than decend the plane decides to climb about 700 ft then begin a rapid decent smack into the perimeter fence.

Been practising around Rotterdam EHRD rwy 24, arriving at 2000ft and 145 knots.

I have the CRS bug set to 239, Nav1 active and set to ILS Freq 108.30, nav mode selected with VOR/LOC selected. I can pick up the localiser and the bird does turn onto the approach path, upon aligning I switch to APR hold yet when I cross the G/S marker I climb to 2700ft, then nosedive into the fence at around 165 knots.

I'm I doing something stupid or do I have a gremlin?

Craig
 
Craig....seems your method is okay....I'm guessing your approach altitude might be a tad high....approach the glideslope from below and your aircraft will capture it just fine. I personally rarely use the NAV/LOC unless the rwy does not have a glideslope beam, I tend to hit the Approach button about 12 to 20 nm out, when within 30 degrees of the localizer, at less than 180 kts and around 1800 feet agl (which is well under the glideslope beam at that distance). The aircraft will align with the Localizer, then start down the beam once it reaches it inbound......each to his own, I guess.

All the best,
Terry
 
Catching the GS in FSX - consistently for each attempt - has always been hit or miss for me (localizer capture is normally easier) but I have recently found hitting the Approach button much further out works best. Sounds like you are pressing pretty late in the proceeding.

GPS/Nav must be switched to Nav. Also use HDG in the AP to keep her aligned with the runway and green ILS symbol on the map. Alt around 2,500 and IAS should be more around 140-50 with the wash all out. Also check that your stick/pitch wheel is calibrated - that can cause mayhem holding the GS if it is not centered properly. Also some airports' ILS seem to "work" well, while others don't, e.g. London Gatwick seems to work. Also, be sure that the opposite end of the runway does not have the identical ILS freq - some airports do this - which may mean you are grabbing the backcourse ILS which will also ruin your approach.

Good luck.
 
With tube liners, make sure you have 5 to 10 miles approach distances, otherwise your ship will usually not be able to climb/dive at the right speed and will end up getting flustered. One thing that some big planes will do is try to dive suddenly (when you are too close) and then it has overflown the touch down point, even in a rapid descent.

Try saving a flight point on approach, far away, at least 4 to 10 miles out, paused in the air, radios and CRS tuned to the ILS runway and then you can reset the flight over and over, practicing things to get the hang of it. The way it 'should' work, is the plane will attain the beam and slowly and precisely descend to right above the runway.

Note also, there are several runways in the virtual FS world that are messed up with their stock ILS beams and will put you down in the dirt or off to the side. Only a few of those though, so the chances of finding one is slim. But, incase your luck is bad, try a different airfield if you cant get this bird down with ILS.


Bill
 
The key altitude will be the final approach fix, which for your purposes will be at 1500 ft 5 miles from the end of the runway. Other items to consider your weight and speed, just before GS intercept you should be fully configured with gear and landing flaps. Some FS planes do not do ILS very well, you might try another plane. Do insure that for landing you are down to about 10-15% fuel, for the 737 a typical approach speed would be about 135 knots.

It sounds as if you are experiencing airplane issues and not something you are doing wrong. Again try another aircraft.

Good luck. T
 
Thanks guys, had to pop out for a bti there going to give it another go. The scenario I described previously was lined up around 10 miles out in the default 737-800, figured since it was the aircraft in the tutorial I watched that it should work :p.

Round two coming up...

Craig
 
Managed 3, one in the 737 and two in the A-321. Thanks Fliger seems I was coming in too high, dropped my approach to 1500' and it picked up the G/S first time. I'd been basing my attempt on the Amsterdam-London mission which has you coming in at 2000'. Now to find some truely horrible weather and see what happens :icon_lol:

Craig
 
Normally in the737 you must have both NAV rxs tuned to the ILS as one does the vertical profile the other the horizontal. So as soon as you have grabbed the GS you need to enable the second autopilot, to follow the GS correctly.
 
This is very helpful info. I have read many time elsewhere that to come in under and capture correctly the GS beam you need to be at about 2,500' altitude. Seems here people get good results at 1,500' so I will give that a try next time.
 
I'm not sure about Europe or other locations but for US you can go to this site and download current Terminal Procedures (approach plates and a lot of other charts/materials).

http://aeronav.faa.gov/digital_tpp.asp?ver=1207&eff=06-28-2012&end=07-26-2012

To get the best results, it is best to use the approach plates. The ATC on FSX normally vectors you to get established on the localizer within 10 to 15 degree cut offset of the runaway heading/ILS course. In my preplanning, I normally have all of that ready prior to the flight and do my own terminal procedure/approach/landing brief/check to make sure everything is good to go. As I'm being vectored inbound to the localizer course, I get everything set on the radios, reviewing the intercept/entry course/altitude and OBS/course selection and double check it most times using the identifier. With many of these FSX autopilots you can arm the approach and intercept the localizer & glideslope just fine and going manual during the final 1000 or 800 ft Rdr/Alt(AGL). Using the automation helps with the workload but some of the models/autopilots work a bit crappy so be on guard for things going haywire during your instrument scan. You can fly the ILS completely by hand also. With the jets and turboprops, things happen quickly and staying ahead of the curve is harder. Getting to the basics, hand flying and ILS in a C-172 and then moving up to the RG and then Twins is a good way to sharpen skills without pressing yourself into a high workload.
 
It should not normally be necessary to tune both nav recievers to use an ILS, the GS is channelized to tune along with its Loc freq. The only reason that two or three autopilots are used is to provide fail passive and fail operational backup for CAT III A and B approaches. These will automatically select at GS capture in Appr Mode.

T
 
Not to stray too far OT, but isn't it true as well that not every ILS provides a GS function. I know if you fly the backcourse that's true obviously, but I'm talking about the primary ILS approach.
 
If there is no GS it is then called an Localizer approach. There a also LDA approaches which may be at some angle to the runway. Without a GS the minimums are higher. In the 747 we have V Nav to assist in making a continuous smooth descent.

T
 
fliger747 said:
If there is no GS it is then called an Localizer approach. There a also LDA approaches which may be at some angle to the runway. Without a GS the minimums are higher. In the 747 we have V Nav to assist in making a continuous smooth descent.
T
Click to expand...
Ok, thanks!:salute:
 
expat said:
This is very helpful info. I have read many time elsewhere that to come in under and capture correctly the GS beam you need to be at about 2,500' altitude. Seems here people get good results at 1,500' so I will give that a try next time.
Click to expand...
The thing to remember is that the glideslope beam can be likened to the hypotenuse of a right-angle (3-4-5) triangle where '5' is the GS, '4' is the distance along the ground from the aircraft to the runway and '3' is the height of the aircraft above the ground.

The further out from the runway you are the higher you must be to intercept the GS beam.

You are correct in saying that you are always better off to intercept the GS from below but if you fixate on flying at 1500' AGL you will be very close to the airport when you do intercept the beam and then have less time to get all your ducks in a row for the landing. I find it better to lock onto the GS beam earlier rather than later which means doing it further away (even up to 15 miles away in a commercial jet) and higher up. Remember too of course that you should be in landing configuration (correct flap setting and gear down) before you intercept the GS beam otherwise you could easily lose the beam due to the aircraft pitching nose up/down due to a change in flap/gear settings after you have locked onto the beam.
 
Tako_Kichi said:
You are correct in saying that you are always better off to intercept the GS from below but if you fixate on flying at 1500' AGL you will be very close to the airport when you do intercept the beam and then have less time to get all your ducks in a row for the landing.
Click to expand...

Not to mention you will likely be below legal minimums for many approaches. In fact, MOST approaches.....

If I pull up the plate for ILS 05 into Lakeland Florida, which I fly for real very often, the absolute minimum altitude I can possibly intercept the GS is 1700 feet AGL. Mind you, this is over flat terrain where the field elevation is only 143 feet. I'm not allowed to descend any further until I am past the IAF (WIREY) and am established on the localizer (needles are deflecting). Experience in making this approach with vectors from Tampa is that the controller will typically not allow you descent past 2000 until you are past WIREY and established.

The fact is if you fly it legally YOU ARE going to intercept the GS from below, there's no other way to do it. Study the chart below and you can see what I and Tako_Kichi mean. Incidentally, the ILS is a PRECISION approach, which is what I think people were trying to say earlier in the thread. You may make a Localizer approach here without the vertical guidance, but at that point it becomes a Non-precision approach with corresponding minimum to 460 feet with 1/2 mile visibility (versus the lower 336 feet with 1/2 mile visibility). This would still be more precise than a VOR approach (another type of non-precision approach) due to the width of the beam as opposed to the radial of a VOR. But it's still non-precision without the vertical.

BTW, in the flight sim I tend to fly the approach under VFR rules despite the simulated conditions. If you don't the ATC guy in your box is going to drive you insane. If you do that, you need to fly the entire approach since you will get no vectors.

View attachment 69165
 
My usual procedure is to engage the app button as soon as I get a glideslope signal on the VOR/HSI/PFD/ (usually about 18 miles out, as long as it shows I am below the glideslope). I also use heading hold to get me close to the proper point for intercept.
 
Note that the glideslope coverage extends only to 10NM. Outside 10NM you might capture/follow a false glideslope that leads you into the terrain well ahead of the runway!
 
Indeed, though ten miles out one should be about 3000 ft above touchdown elevation. I do occasionally have this issue with First Officers being a bit over eager to push the APP button rather than the LOC button. Another issue here, though not applying to FSX is the step-downs seen further out on the Localizer may not follow the GS exactly, and premature capture of the GS may nip into airspace protected for other arrival departure paths etc. So follow the charts and or ATC instructions, at least IRL.T
 
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