Flying an ILS in VMC (Low hour PPL)
 

Good Afternoon All,

***Please let me start by saying that I understand this was covered a number of years ago, but as I don't understand it much, I'm asking again. Also, please understand that this is JUST a question, I have no intention of being in a situation where I have to use it before I've done my IR, or at least IR(R). I am a very low hour PPL.***

So, my question is this. My understanding of an ILS is that it is used to assist a pilot with lining up with the runway, and descending in such a manner as, even without outside references, they can land safely. Is that correct? Now, I have NO idea how one would even start to use an ILS (so if someone has time, it would be great to get a rough overview of how it works), but, if I asked to be taught it at the flight school, prior to starting instrument training (funds don't currently allow me to do the proper course), would that be acceptable?

I gather that, in the hugely unlikely event (unless you've done bad planning) that the weather closes in around you whilst en-route (and by closes in, I mean, really, closes in), you COULD ask for an ILS at your nearest airfield to allow you to land safely, if you were able to use it? Surely that would be a safer way to get you on the ground?

Hope that all makes sense. Basically, if I was able to be trained to use an ILS (but without gaining my full IR or IR(R), would I still be able to use one just to practice, in VMC?

Thanks in advance


T

Hi

Flying an ILS is an IFR technique that requires you to be able to fly 'on instruments'.

This means being able to fly using other instruments than the ILS readout. It is no good having the needles in the right place if you are in a 45 degree bank. If you are focusing on the ILS needles then you are not looking out of the window so need to have a good instrument cross check to remain at the correct attitude etc. All this is taught on an IR(R) course before starting on the ILS stuff for that reason.

Flying around on your own in the vicinity of an airfield practising an ILS without instrument flying tuition would be a VERY bad idea whether it is legal or not, which I am sure it isn't.

Do yourself a favour and get an IR(R). It will improve your flying and allow you to fly an ILS etc. If funds don't allow then stay VFR until you can afford it.

If as a low houred VFR PPL you found yourself in weather you are uncomfortable with, fall back on your very short instrument appreciation lesson, keep the wings level, declare a mayday and let a radar unit talk you to either better weather or as a last resort a surveillance radar approach, do not try to fly an ILS with virtually no instrument skills.

If you find yourself in a 45 degree bank while supposedly flying an ILS, having the needles in the right place is the least of your worries!

I do completely agree with Prophead though. If you just want to get a feel of what instrument flying (including an ILS) is like, a PC sim is a pretty decent way to do it. Plus it will happily throw in things like gusty crosswinds and up/down drafts. Instrument flying is first and foremost about flying on instruments. Once you can do that reasonably happily, THEN it is time to start trying to fly approaches.

Very good advice from the previous posters.
To the OP: before running you need to know how to walk. Shooting instrument approaches like the ILS is based on controlling the aircraft using the instruments only, which is based on scanning them and interpreting them first.
It's not advisable or feasible to skip the very foundation on which instrument approaches are built.

+1, in fact agree with all the above.

Back in the day when I taught Instrument Flying (IF) the first "let downs" taught were basic cloudbreaks ( initially a basic straight line descent to MSA, later on turns were allowed...), then moved on to survellance radar approaches (SRA), then on to PARs (!!!) and only then with perhaps 150 ish hours flying under their belt, and more importantly maybe 20+ dedicated IF hours "under the hood" were the students taught to fly a basic (raw data) ILS....now it no doubt can and is done sooner these days in the commercial training schools which have a higher emphasis on procedural IF than where I taught but nevertheless flying an ILS safely really requires a solid grasp of IF skills and a good solid IF scan...if you don't have that you will more than likely end up at 45 AOB or more, or stalled/overspeeded, or worse, due to chasing the ILS needles...

Having a go in a "sim" at an ILS is fine, but IMHO you'd be playing with fire as a low houred hour'ed PPL even thinking of attempting an ILS on the aircraft in marginal conditions. In the real world if you do get stuck above weather then as has been recommended, a "mayday" and hopefully help with a cloudbreak is a much much safer bet for a low hour PPL then an ILS.

Why do PARs get !!! ? I did one only a couple of weeks back in IMC - common and very useful at military airfields.

Yep,sorry, my fault, it's been a while and in a senior moment I forgot that of course they are still very much around in the mil world...and yes, very useful and IMHO much easier to handle than a raw data ILS.....

Forgive me for being a bit obtuse, but what part of intercepting the localiser is any different from intercepting and flying a VOR radial?


As for following the Glideslope, or the PAPIs, that will put you on a 3 degree glideslope, and is not really what is required for VFR GA aircraft.... Is there a recommended glideslope for GA aircraft, I have heard 6 degrees mentioned, but why..
.

(1) As you get closer to the VOR the needle gets twitchy, but it doesn't matter if you lose it - you're just about to pick up your next leg to your next navaid anyway, it doesn't matter if you miss directly overflying the VOR by a few hundred yards.


(2) As you get closer to the ILS the needle gets twitchy, but it does matter if you lose it - you're wanting to land on the runway so it does matter if you miss it by a few hundred yards.

This is what training is for, even as a low hour start thinking about the IRR

To put it in context, soon after getting my IRR I flew a real live ILS approach in real live IMC. No instructor beside me, no-one else in the plane, no chance of a sneaky peak outside the hood. No chance of a second chance and no reset button.

Breaking out of cloud to find the runway where it should be was one of life's Eureka moments. But I hadn't realised how much it had drained me until I tried getting out of the cockpit, my legs had turned to jelly and my shirt was sopping wet.

So don't underestimate how taxing flying on instruments can be, especially real life when a mistake can be your last.

And while we're on the subject of No No's at having a stab at untrained instrument flying, do no think for one second that the synthetic vision feature most VFR GPS's and tablets are equipped with nowadays would be an adequate substitute for proper IF technique in getting you to and down an approach. They aren't, you'd die.

piperboy 84 wrote:
"And while we're on the subject of No No's at having a stab at untrained instrument flying, do no think for one second that the synthetic vision feature most VFR GPS's and tablets are equipped with nowadays would be an adequate substitute for proper IF technique in getting you to and down an approach. They aren't, you'd die."

Please explain why. And if instrument rated?

Instrument rated: Yes (FAA CPL w IFR ticket)
Why: I've tried it on a Garmin 660 and IPad both bluetoothed to a GDL 39 3d for a full six pack and the motion and sight picture presented on the screen did not allow me to fly to what I felt were acceptable tolerances and I certainly wouldn't rely on it. Maybe I needed to be trained on how to fly using that method but it wasn't for me and certainly would not be for a non IR guy trying to shoot an approach in IMC.
As a pinch hitter faced with a vacuum failure or for backup situational awareness, sure. As a primary reference, no way.

Thank you all. As I say, I have no intention of doing it, just purely wondered. The advice about calling a MayDay is evidently the way to do it.

So, on a related but slightly different note, can anyone briefly explain how they work, or is it too much detail for a forum?

Thank you :)

Some Googling will probably help you with that...

Agree with the sentiments above as to flying one without training though... IFR flying is drastically underestimated by some VFR pilots. Having done my IR(R), I can safely say that the last thing you want to be doing is an ILS if you get stuck above cloud without the training. As been said, declare a mayday and if you have to, do an SRA.

Basically as follows. An installation at the airport concerned will send signals providing lateral (localiser) and vertical (glideslope) guidance. This will be interpreted by instruments in your aircraft that will then, provided properly set up and within operational range, provide visual indication to the pilot of your position relative to the design approach path.

If using an ILS, ATC may ask to to fly a procedural approach (possibly starting with a hold) which will then require you to follow a published procedure to 'intercept' the ILS. Alternately, you may be given radar vectors to intercept.

When intercepting, you will first intercept the localiser, which requires a turn onto the appropriate approach heading, allowing for wind correction, adjusting heading as required to follow the localiser needle. The glide path will be above you at that point, and will be intercepted from below. When cleared by ATC to do so, you will follow the glideslope down to decision altitude/height. At that point, you have to go around if you are not visual with the runway.

You do see a lot of pontificating on forums such as "dont try this without training" but in the case of an ILS in IMC, it really is the case - you need both good training and good currency to do it safely.

I've never seen or heard of pilots having an option to choose the glideslope angle on an ILS....you have to find a way fly the published Glideslope angle because you are stuck with whatever glideslope angle was built into the ground installation.

If you try to fudge it to generate a steeper approach by flying with the needle off centre (i.e deliberately flying a dot or two dots above the 'slope) to produce a steeper glide you are into the vaguely uncalibrated and certainly the unknown and all the procedure check heights (e.g marker/DME) would be rendered usless .... all bets would be off .. (and you'd fail an instrument rating...).

https://www.google.fr/search?q=ils+g...UfXX-DAk_pAIM:

Thank you :) Makes sense.

Of course, I'd never try something without being instructed first. It's my full intention to get my IR(R), probably this year, but just saving the funds

If you intend to do an IR or IR(R) in the near future, it would be well worth joining PPL/IR (Google it). You will get a loads of advice and support there. And probably offers of flights where you can see IFR approaches being flown.

You'd be welcome to come up with me, but would require a trek to Cardiff.

The best you can do and what you should practice is a wings level let down on a heading.
No turns nothing.
Carb heat ON, flaps first setting, power reduction and wings level 400-500fpm rate of descent.
You get caught about an overcast, this is how you get down.
Declare an emergency and wings level let down.
Break out below and you should have a runway between your 11 and 1 o'clock.
You can practice this plenty with a flying buddy.
When this happens for real you'll be close to panic and only remember the basics.
In calm stratiform cloud you'll only need the lightest of corrections as a trimmed airplane will maintain a wings level constant rate descent on its own.
You have the right idea ( emergency) but you're making it too complex ( ILS approach)

That sounds great, I will join (when I've got membership fee spare), and would love to do some flights with an experienced IR pilot jut to see how they're done. Thank you so much for the offer, if I'm ever that way, and you're flying, I'd love to :)




Thank you B2N2, I'll get practising those :)

tobster911,

I agree with B2N2, good advice. Make your buddy an I/R rated pilot who can file an IFR flight plan so you can legally go into cloud - that way you're legal and safe if wings level turns into anything but!

Also, someone before mentioned using Flight Simulator. I couldn't agree more. Back when I did my IFR ticket, I used MS Flight Simulator for the basics: getting my "scan" going, beacon bashing with and without wind, basic ILS work, etc. The beauty thing about this is that you can set a place in space and time and change the conditions - start out a 5,000' heading north to a beacon in IMC and fly over the beacon. Then go back to your starting point and add a 30* crosswind at 10 knots. See how things change. Do it again with a 60* crosswind at 10 knots. Then 90* @ 10. Then up the wind - 15 knots, 20 knots, 30 knots, etc. See what corrections you have to make to stay on track.

It is a great way to see the theoretical aspects play out in a nice, easy "practical" setting where the only thing getting hurt is your heat sink and the only thing you're paying is the electric company.

Spooky, but I had to do the ILS.....
 

Having got my IMC in Faro, where they didn't have ILS back in the day (80s), I had only performed VOR/DME and PAR (latter into Gibraltar). Then in UK I got caught above cloud and the ONLY option available (due lack of radar and reducing fuel) was an ILS. Fortunately I was very current on instruments and managed to hack it - but wouldn't recommend to anyone to try without training. I was fortunate on the day, and Pilot mag are due to publish the ILAFFT article sometime over next few months. Readers may think "plonker" but we've all done something and this was my big learning curve..........still here and flying nearly 30 years later.

Simulator was the thing which finally got the NDB tracking and approaches clear in my head.

My airplane has wizzy, wizzy autopilots and ILS - all I have to do it tweak the throttle.

That said - first time I gave it a go - autopilots captured the ILS about ten miles out, turned to the runway, the glide slope on the STEC at about 7 miles out, tweaked the throttle and sat back fascinated at how well it did it.

Now the big problem, I was transfixed by it, getting nearer to the runway a shortish final - now thought "how do I switch it all off and land?" - all I really had to do was push the disconnect on the yoke, was not too sure so thought I would reverse what I had done to switch it on. Meanwhile airplane is now over the rabbit lights, nicely on course - got it all switched off as I was passing over the numbers at about 20ft, throttle back, flared and landed - never again!

I think the earlier comment that if one is messing with ILS one really needs to be able to fly by instruments - even if it is daylight and otherwise perfect. I don't use it anymore, but it is worthwhile having in case all else fails - down here there aren't too many alternates so one day I may need it - now I know to just check the trim lights are out and press the button.

Must do something about getting a IR one day.

How does it work?
https://upload.wikimedia.org/wikiped...lustration.svg
Localizer at the far end of the runway (so aircraft on auto-land can use it to stay on the runway in zero visibility) transmits two lobes at different modulations on your selected frequency. Your aircraft's reciever interprets what it detects of the two signals and displays it as a "fly right / fly left" indication.

Glide slope aerial also transmits two lobes but on a paired frequency in the 300MHz range. Your receiver knows automatically which frequency is paired with the selected localizer frequency. It interprets the two signals to give you a "fly up / fly down" indication.

The shape of the lobes mean that you are funnelled onto the runway (so close in, a small deviation will move the indicator a long way).

There is a technical limitation / gotcha (which you would be trained for on an instrument course) in that the lobes can be picked up incorrectly if you are too high - so instead of going down at 3 degrees, if you follow them you would descend at a much steeper angle - so the training is especially important! A few airliners have come to grief that way.

HTH

Riverrock83 - Thank you very much. That makes a lot of sense. It's so clever.

Absolutely, I think some people were missing the point of the post. I'd always undertake training, but just wondered if it was something that could be taught outside of an IR or IR(R) course, but I understand that it's not really. Hoping to do the course towards the end of the year, all being well.

Thank you :)

Providing you fly visually there is no reason whatsoever why you can not follow an ILS. But what will you achieve by doing so? Firstly, there is the distraction. Then there is the looking out vs looking in and then lastly, there is the difference in technique. A visual pilot would typically set speed by attitude and ROD by power. When flying an ILS corrections typically start by using elevator to maintain the glide (which is fixed to the glideslope) and power to control the speed. Eventually it is still a power plus attitude equals performance equation, but the way yin get there is difficult.

Learning how to fly an ILS by yourself will probably lead to poor technique. So how can you start by yourself? Firstly learn to trim "gram perfect" and by that I mean whenever you let go of the stick the aircraft will fly for minutes doing whatever it was before you let go; same speed, heading and altitude. Now learn the magic numbers for your plane. At 2,000' your plane will require X degrees of pitch, Y rpm and will deliver Z knots. Learn the same at 3,000'. Now learn the numbers for different speeds. Now do the same for descents and climbs so you can deliver a set ROC/ROD at various airspeeds. Do the same for different configurations. It may seam over the top but if you can get the aircraft to do exactly what you want just by setting pitch and power, learning to fly on the clocks will be a doddle because you won't have to think about flying. It will give you the time needed to think what you need to do next and where the aircraft will be in the next few hours, minutes and seconds. Now you are ready to start learning to fly on instruments but you will also be a better visual pilot.

PM