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Can I set a semi/auto landing at a non ils airport?

https://www.nzff.org/viewtopic.php?f=1&t=12633

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PostPosted: Sat Aug 21, 2010 5:52 pm
by Pete1800ftmin
Hi there guys.
I have recently worked out how to set up a ILS landing,and since then I have been really enjoying those perfect approaches into the larger airports.I am wondering though,is there any way I can get a similar automated approach and descent into the non ILS airports.Or am I confined to a eternity of those jolly hit and misses!!
Regards Pete1800ftmin.

PostPosted: Sat Aug 21, 2010 7:49 pm
by Dion500
Do you mean like a VOR or NDB approach? The only problem with those is you need the aerodrome plate to get the distance steeps, which flight sim doesnt provide.
Or you could just use the good ol' PAPIs

PostPosted: Sat Aug 21, 2010 9:43 pm
by mfraser
Hi there,

In 'real life' true autoland systems require a CATIII ILS and a radar altimeter equipped aircraft - however in FS you can get by with just the standard CATI ILS and pretty much any aircraft. Most of the payware aircraft feature an autoland function (With varying degrees of success) - the default ones don't. True autoland systems use the aircraft autopilot and radar altimeter to judge the height above the runway and flare the aircraft appropriately during the final stages of landing - whereas the default aircraft will simply land flat or nose wheel first which isn't as realistic (And will probably cause a crash or significant damage). In this case, just use the APPROACH function on the MCP/autopilot and disengage it on short final and flare the aircraft yourself..........

So, the short answer is no, unless there is an ILS you can't use autoland as the aircraft receives no glideslope information. You'll have to follow Dions suggestion and manually manage the descent profile of the aircraft yourself.......

If you don't have the approach plates here's an easy rule of thumb to maintain the standard 3 degree approach angle. Simply multiply the distance from touchdown by 3 (and then multiply the result by 100)!! For example............

at 10nm from touchdown you should be about 3000ft (3x10=30 and 30x100=3000ft)
at 5nm about 1500ft (5x3=15 and 15x100=1500ft)
at 2nm about 600ft
at 1nm about 300ft etc etc etc

It gets easier the more you practise it - and during an autoland/autopliot managed approach its a good way to verify that the system is working and maintaining a correct (And safe) profile!!

Hope this helps!! rolleyes.gif
Mat

PostPosted: Sat Aug 21, 2010 9:54 pm
by Chairman
And don't forget the PAPI that Dion mentioned biggrin.gif

That's the red and white lights beside the start of the runway - you want them to be half white and half red. If they are more than half white you're too high, if they are more than half red you're too low.

You can watch this by changing to spot view while the plane is getting close to landing itself on an ILS runway - the PAPI is linked to your eyepoint not to the plane, so as you move the viewpoint up and down you'll see the PAPI changing. Makes it an absolute bugger to get screenshots with them showing half and half !

Cheers
Gary

PostPosted: Sat Aug 21, 2010 9:58 pm
by mfraser
Chairman wrote:
QUOTE (Chairman @ Aug 21 2010, 09:54 PM) <{POST_SNAPBACK}>
That's the red and white lights beside the start of the runway - you want them to be half white and half red. If they are more than half white you're too high, if they are more than half red you're too low.


Yup...... Warren Satlers words are still engrained in my brain from 20 years ago!! All white is alright....... all red and you're dead!! winkyy.gif

PostPosted: Sat Aug 21, 2010 10:25 pm
by Pete1800ftmin
O.K,thanks for all that info.I am going to work out that descent maths,and see if I cant get things more consitent in my landings.I guess what I want to know is when I go down to Nelson airport and watch the Dash8's come in,why are they bang on EVERY time.What are they doing?Is it all visual without ILS.Or is it about those 'plates' you were mentioning?
I will have a good look at those descent estimates i.e(5nm=15=1500ft)and see how I go.
Thanks again.Pete

PostPosted: Sat Aug 21, 2010 10:33 pm
by Pete1800ftmin
mfraser wrote:
QUOTE (mfraser @ Aug 21 2010, 09:43 PM) <{POST_SNAPBACK}>
Hi there,

In 'real life' true autoland systems require a CATIII ILS and a radar altimeter equipped aircraft - however in FS you can get by with just the standard CATI ILS and pretty much any aircraft. Most of the payware aircraft feature an autoland function (With varying degrees of success) - the default ones don't. True autoland systems use the aircraft autopilot and radar altimeter to judge the height above the runway and flare the aircraft appropriately during the final stages of landing - whereas the default aircraft will simply land flat or nose wheel first which isn't as realistic (And will probably cause a crash or significant damage). In this case, just use the APPROACH function on the MCP/autopilot and disengage it on short final and flare the aircraft yourself..........

So, the short answer is no, unless there is an ILS you can't use autoland as the aircraft receives no glideslope information. You'll have to follow Dions suggestion and manually manage the descent profile of the aircraft yourself.......

If you don't have the approach plates here's an easy rule of thumb to maintain the standard 3 degree approach angle. Simply multiply the distance from touchdown by 3 (and then multiply the result by 100)!! For example............

at 10nm from touchdown you should be about 3000ft (3x10=30 and 30x100=3000ft)
at 5nm about 1500ft (5x3=15 and 15x100=1500ft)
at 2nm about 600ft
at 1nm about 300ft etc etc etc

It gets easier the more you practise it - and during an autoland/autopliot managed approach its a good way to verify that the system is working and maintaining a correct (And safe) profile!!

Hope this helps!! rolleyes.gif
Mat

Thats really helpful.What about lining up to the runway?The GPS doesnt seem to tell me which way the angle of the runway is situated,so that I often am coming in slightly left or right,if you know what I mean.In non ILS approaches is there at least a way to get me locked onto the runway?Pete

PostPosted: Sat Aug 21, 2010 10:42 pm
by Dion500
If the vis if good enough, they will request a visual approach. Where the tower will tell them to join downwind or base, or straight in, or what ever, and they go from there. They would be using the PAPI in that case, makes life so much easier, they guide you right to the 1000ft markers.
But if they cant get visual, they would have to use the approach plate, which is a piece of paper that tells them all the info they need for the approach. Im not sure what approach Nelson is, VOR/DME i guess?
It would tell them what radial from the VOR to be on. And things like at 5 nm, no lower than xxxxft, at 3nm, no lower than xxxft and so on. So they kinda step down, hence the name distance steps (i think thats the name anyway winkyy.gif ) Until they get visual on the runway, then the PAPI takes them in from there.

But yeah, your best bet is the PAPI, the only problem with them is they dont really work through cloud.

Just keep practicing really, you have to build pictures in your head about how an approach should look like, and they only come with practice. Doing circuits is the easiest way to do that, even if its in a 747.

PostPosted: Sat Aug 21, 2010 10:47 pm
by Ian Warren
If you are using the default 737 , a good ILS trainer and into Auckland , you want to aim approx 15 kms out at approx 3500 ft , if you have set your radios correct you can let the 737 auto-fly and land , .... Question , are you running FSX or FS9 , FSX i can help being copilot or even better still you could call the assistance of Waka172 a regular real time pilot just returned to the forums as your copilot .

PostPosted: Sat Aug 21, 2010 11:38 pm
by Chairman
One of the tricks with visual approaches is to start from the right place, and know approximately how fast to descend - For me in a boeing that's at about 3000 feet with about 10nm to go. From there I'll descend at about 600-700 fpm until I see the separate colours on the PAPI.

The white lights are generally the first thing to pop into view, and tell me where the runway starts. I know the heading along the runway, so once I know exactly where it starts I can tell whether I'm in the right place or need to slide left or right. Don't get hung up on lining up exactly with the runway while you're still 3-4 miles out, a lot can happen in that distance. Just keep it roughly in the right place, and start to tighten it up once you can see the separate red and white lights.

Once you can see the seperate red and white lights (or once you can see distinct individual lights that are all the same colour !) it's just a case of adjusting the power to keep the lights the right colour, and not drifting off to one side.

I really suggest you practise in calm weather and worry about things like wind later, after you're happy with being able to arrive in the right place most of the time in calm conditions smile.gif

Enjoy it, it's good fun smile.gif

Gary

PostPosted: Sun Aug 22, 2010 1:56 am
by Pete1800ftmin
[quote name='Chairman' date='Aug 21 2010, 11:38 PM' post='8265012']
One of the tricks with visual approaches is to start from the right place, and know approximately how fast to descend - For me in a boeing that's at about 3000 feet with about 10nm to go. From there I'll descend at about 600-700 fpm until I see the separate colours on the PAPI.

The white lights are generally the first thing to pop into view, and tell me where the runway starts. I know the heading along the runway, so once I know exactly where it starts I can tell whether I'm in the right place or need to slide left or right. Don't get hung up on lining up exactly with the runway while you're still 3-4 miles out, a lot can happen in that distance. Just keep it roughly in the right place, and start to tighten it up once you can see the separate red and white lights.

Once you can see the seperate red and white lights (or once you can see distinct individual lights that are all the same colour !) it's just a case of adjusting the power to keep the lights the right colour, and not drifting off to one side.

I really suggest you practise in calm weather and worry about things like wind later, after you're happy with being able to arrive in the right place most of the time in calm conditions smile.gif

Enjoy it, it's good fun smile.gif

Gary
[/quote
Thankyou.Are those lights at all runways?Pete.

PostPosted: Sun Aug 22, 2010 11:55 am
by frostynz
QUOTE
Yup...... Warren Satlers words are still engrained in my brain from 20 years ago!! All white is alright....... all red and you're dead!![/quote]

Yep .... theres a lot of things that the old boy said that sticks in your mind ! biggrin.gif

PostPosted: Mon Aug 23, 2010 11:44 am
by cowpatz
Pete there are many ways to skin a cat with regardsto conducting approaches. Most of them have been touched on in posts above but there are some cardinal rules that really help.
3 X the distance is one of them. Multiply the distance to go time 3 to get the height as in mfraser's post. Just make sure that the distance you have is to the threshold or near by or else make an allowance for the difference. ie if the DME is down at the other end of the runway to that in which you are landing on then deduct the runway length from the reading (a 2000m runway is about 1 mile)
Another is to help workout what sort of rate of descent is needed in order to stay on the optimum descent path (usually 3 degrees). To do this look at your groundspeed (or if not much wind your indicated airspeed or calculate your groundspeed. If you are doing 120 kts indicated and you have a 20 kt headwind then your groundspeed is 100 kts). Half your grounspeed and then multiply it by 10. . This will give you the rate of descent needed to maintain a 3 degree slope at that groundspeed. If you change your groundspeed then modify your rate of descent again. Sounds bad but in reality it is easy

100kts GS/2 = 50 x10 = 500 fpm (feet per minute)
120 kts GS/2 x 10 = 600 fpm
180 kts GS/2 x 10 = 900 fpm

So to do the maths the easy way half the first 2 numbers and add a zero on the end.

I have written a couple of articles on flying non-precision approaches that you can find here. They are titled Non precision approach and Non precision approach part 2.

If your aircraft is equipped with an FMC and is capable of conducting an RNAV approach with VNAV then you can basically fly a non precision approach in a similar fashion as you would an ILS approach. This is explained in more detail in part 2. You will need an aircraft that is capable though such as a PMDG 737, 747 or MD11.

In other aircraft if you intend to fly a non precision approach (anything other than an ILS) then use the autopilot. If it is a VOR approach then use the VOR/LOC (or might be called NAV) function of the autopilot control panel to track the inbound course. Use the Vertical speed (V/S) pitch function to maintain the descent path using the methods described above. Ideally you want to be able to see what rate of descent you are setting and have control over it to within a 100 fpm. If you have tool tips selected then usually when you pass your mouse cursor over the vertical speed control knob it will tell you what the fpm value is. This can be fine tuned by rolling your scroll wheel on your mouse (if fitted) or by clicking on the appropriate click spots as per usual. The published approach charts will also assist in determining what altitudes you need to be at on various parts of the approach and some will have distance versus's altitude data for the final portion of the approach. NZ charts can be found here.
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