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PostPosted: Fri Nov 28, 2014 7:25 am 
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Hello All,

Since the release of A2A’s excellent Cessna 182, I’ve decided to make a concerted effort to improve my instrument flying skills. I’ve no real-world aviation experience, but since early FS5.1 days I’ve been interested in ‘old school’ VOR-to-VOR and ILS type flying and I hope I’m reasonably familiar with the principals. However, please forgive me if I come at this in a rather confused way! :wink:

In practice, I can do a reasonably good job of hand-flying set headings and altitudes under IMC. I can also fly visual approaches and landings without too much drama. However, it’s when I try and combine the two that things often go awry. I’ve real quite a bit of guidance such as extracts from the FAA Instrument Flying Handbook and threads such as this one on PPRUNE where rather varied advice seems to be offered.

In general, the main points I’ve taken on board when flying the ILS are ‘don’t chase the needles – fly a heading and V/S’ and ‘scan like crazy’! To be fair this usually works pretty well until the last 300-400ft before minimums. At this point I find myself tending to overcorrect and some fairly extreme attitudes can result. (I should add that in FSX I tend to set-up a rather artificial scenario where I need to fly right down to about 220ft AGL on instruments before I get any visual reference with the runway environment.) Anyway, here’s an initial question aimed squarely at those real-world instrument-rated pilots on the forum:-

• Is the lack of physical sensation in the sim a help or an obstacle in IMC flight? (I realise there’s not much I can do about this, but just interested to hear opinions.)

I’m trying to analyse why my ILS approaches become unstable at this point. Obviously the needles are much more sensitive as I approach the localiser. However, I feel the culprit is partly that using a rather springy joystick (Logitech Extreme 3D Pro) I tend to introduce an unwanted pitch command whilst trying to adjust heading (and vise-versa), So, question two:-

• Have any of you found switching to a yoke significantly improves your instrument flying?

The reason why the C182 is my preferred instrument platform is, of course, because of A2A’s excellent rendition of the KI 525A HSI. I find that (presumably because this simplifies my scan) my lateral control when using it is a lot better and the HSI is certainly a wonderful instrument. However, here’s another question:-

• Does using an HSI encourage bad habits including the ‘needle-chasing’? I’m not sure…

In general though, I’d say my pitch control on the ILS is much worse than my lateral control. Partly this is because I struggle to have the aircraft perfectly trimmed without visual references. This leads me to a little thought/question for A2A:-

• Would it be technically feasible to introduce a ‘cheating’ trim indicator under one of the shift + number windows? By this I mean a graphical indicator of how much force the yoke is applying? (Perhaps this info is available in the sim for force-feedback hardware.) I’d envisioned a kind of discreet vertical slider which would become centred as the aircraft moves towards being properly in trim and one can relax control input.

Anyway, If any of you are able to offer any suggestions/tips to help stabilise my ILS approaches I’d be grateful. Rob (‘Great Ozzie’) has already recommended the 'additional instrument flight maneuvers’ PDF. The flight patterns it describes look even more daunting than the ILS, but I’ll certainly give them a try! I do seem to have a tendency to balloon out of turns whilst flying on instruments, and I can’t just keep blaming my joystick... :roll:

Thanks,
Nick


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PostPosted: Fri Nov 28, 2014 7:54 am 
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Nick,

Some ideas that have worked for me..purely from sim point of view! I'm interested too if instrument guys around here could give some good tips! :)

The main points you give are the key I think. First keep the thing upright. Then fly the heading, and fly the VS. What I don't believe so to say is the tip to 'scan like crazy'. At least for me, that leads into trying too much.

I think like I've got too sets of scan going on simultaneously. First is the normal instrument scan, I go through the attitude, turn indicator, heading, vertical speed and airspeed. This is to keep the airplane on, or return it to, the parameters you've got when stabilized on the approach. Those are my targets, not the needles.

The second scan concerns the ILS needles (and ADF needle if I've got a locator there). I just check them once every while: if the localizer is to the left, I just adjust my heading target to the left a bit. When I see it comes back to center, I return to the original heading (plus and minus some if I feel I need to adjust my wind correction). If I'm too high, I just increase the vertical speed for a moment in similar manner.

If you scan like crazy, I think you'll want to relax that quite a bit. It works fine for me to just fly the airplane using normal instruments - fly the headings and vertical speeds, check the needles every now and then, and adjust the targets as required. And deviations are acceptable in short term. Just make prompt heading and vertical speed corrections, and hold the values. But more relaxed scan I've got, the better the approach will usually be.

-Esa

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PostPosted: Fri Nov 28, 2014 8:25 am 
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You already have good advice in hand in not chasing needles and flying a course and V/S. Stabilize on those parameters and then make lots of small and immediate adjustments as required.

I think that getting in the habit of making immediate corrections and very small ones at that is very important. Once the deviations get large then it gets progressively harder to fix the situation.

I don't think the controls are really a problem. Make sure you trim out early to reduce your workload and do not stop scanning and focus on a single instrument as that will really spoil things quickly.

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PostPosted: Fri Nov 28, 2014 10:22 am 
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Thanks chaps. Esa - yes the 'scan like crazy' remark wasn't very well phrased! In fact one of the articles I've read reinforces the exact point you made: Simplify the Approach, and Slow Down the Heartbeat.

So yes, a relaxed but effective scan would perhaps have been a better way to put it. However (as Oracle mentions) I find that if I neglect the AI for more than a couple of seconds (typically for the HSI :roll: ), that's when the pitch starts to get away from me.

Speaking of pitch, I tend to use a constant power setting, trim as best I can and use small joystick movements to correct pitch. Using power to control pitch seems too slow in this regime of flight, although I guess this is another whole debate?

For what it's worth, I've been flying the approach from the FAF at a rather sedate 75kts or so (with 20° of flap). I know this could make me wildly unpopular in real life but it gives me a better chance to stay ahead of the aircraft...

Cheers,
Nick


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PostPosted: Fri Nov 28, 2014 10:51 am 
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Yeah, it's quite easy to let the airplane leave the stable approach. In the sim the instruments are quite hard to read precisely at my resolution, so I tend to double check the AI with turn indicator. It is easier to make sure you're keeping the plane going straight. Regarding the pitch, good trimming is essential, at least with my joystick. I find it easiest to do vertical adjustments in both elevator and power - just like in VMC, 'up-command' is a bit more power, and slight pull on the elevator. When correction is done, and if you're trimmed correctly, then just return both as they were and carry on.

If I happen to get a larger deviation from the localizer, I usually forget the needle completely for a moment, and perform a kind of shallow S-turn with heading indicator. It is surprisingly easy to straighten right back on the localizer. In vertical sense, if I'm much off the glide there is little more to do to either increase the sink to somewhere around 900 fpm or so, or decrease it to about 200 fpm if below. If I don't see an immediate improvement, it is usually best to go around.

-Esa

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PostPosted: Fri Nov 28, 2014 1:23 pm 
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Nick M wrote:
Speaking of pitch, I tend to use a constant power setting, trim as best I can and use small joystick movements to correct pitch. Using power to control pitch seems too slow in this regime of flight, although I guess this is another whole debate?


Not sure if you meant to say something power controls the angle of descent, but power shouldn't control pitch as it is the elevator controls pitch. Be proactive with the yoke and hold that nose exactly where it needs to be regardless of power or trim changes. Practice a methodical scan technique so that you avoid tendencies to lock in on one instrument.

Another thing I've been taught is for small corrections on final, use small inputs with only the rudder pedals to fine tune the path on the localizer instead of small banked turns.

I don't know about the 182, but a 172 would generally fly an approach at 90KIAS and this reminds me of another point. Don't forget to time the approaches from the FAF as you need that data in case the glideslope were to fail.

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PostPosted: Fri Nov 28, 2014 2:13 pm 
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Oracle427 wrote:
Don't forget to time the approaches from the FAF as you need that data in case the glideslope were to fail.
Forgive me for getting a bit out of topic, but I've seen this mentioned every now and then in literature. I'm curious if this is the way it is done by some? I mean, I'm not sure if it was legal or not, but I most certainly wouldn't switch over from ILS approach to LOC approach 'on the fly', but go missed instead. Quite many reasons for that, first of all, the conditions should meet the minima for LOC approach (they won't necessarily do that and should be separately checked - though very often they are on same chart making it trivial); moreover, that could put me into position where I might already be under LOC approach's MDA necessitating an immediate go-around anyway, and I certainly would like to prepare myself mentally for only one approach at the time. I just wonder, as I'd consider continuing the approach without ground contact when any kind of non-redundant equipment failure is met a kind of bad practice. In reality, I mean - in simulator it sounds like fun! :)

I don't mean to say that timing would be bad idea, of course not, but I'd say that continuing on ILS approach without an ILS would be - unless the approach was considered a localizer approach from the beginning.

-Esa

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PostPosted: Fri Nov 28, 2014 2:21 pm 
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Yes, you are 100% correct Akar about flying the ILS to a landing. If the glideslope went out mid approach, going missed would be necessary as one isn't cleared for the localizer approach anyway.

You could get re-cleared for the localizer only and fly it down to minimums and landing, but it is awkward and can be dangerous if one isn't mentally ready for it.

The issue you have is how do you go missed without the glideslope? Where do you turn? How do you know if you have reached the MAP without the glideslope so you don't potentially turn into that tower or hillside before the MAP? With just the localizer you only have altitude and lateral position, but no way to determine if you have reached the MAP.

Of course GPS is a great SA backup. :) :) :)

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PostPosted: Fri Nov 28, 2014 2:31 pm 
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All good points. I understand that ILS specifically doesn't have MAP, but the DA replaces it. Not sure if this is always the case, but most missed approach procedures that I've flown in the sim, and which are terrain critical, usually require DME (in form "fly that track until x DME, then turn"), or you to cross another type of fix before commencing the turn. I think all the missed approach procedures are laid out so that they can be flown from any point, and often your go-around speed is much different from final approach speed anyway, which would make at least my timings go difficult.

-Esa

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PostPosted: Fri Nov 28, 2014 2:47 pm 
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I haven't come across very many ILS in this area with DME. What you usually have only is timing or a radial from a nearby VOR to define an intersection, or GPS to find the intersection.

You cannot rely on DH without glideslope because you can potentially reach the DH well before or after the MAP on the LOC only version of the approach.

Check out ILS 3 for KMGJ. Timing is technically the only option you have. BTW there is a big hill about 1000' high just as you turn crosswind and downwind from RWY 3, you could hit it even if you climb and turn at the wrong point.

KMMU ILS 23 is not as critical for terrain as KMGJ.

KTTN ILS 6 is has an intersection at 840' which is the same MDA as the LOC only approach, but that does not coincide with the MAP. There are also tall towers just to the right and left of the approach course and very near the runway. The timing on this approach will take you right to the runway threshold before turning.

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PostPosted: Fri Nov 28, 2014 2:51 pm 
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Oracle427 wrote:
Not sure if you meant to say something power controls the angle of descent, but power shouldn't control pitch as it is the elevator controls pitch.

Yes, I phrased that rather badly too! I indeed meant to question whether using power as the primary means to control rate of descent on the ILS was appropriate, or is it recommended to use pitch to control vertical speed, adjusting power only as needed to maintain airspeed.

I've read somewhere that whilst students are often taught to use pitch for speed and power to control ascent/descent, this technique is less applicable to flying an ILS, especially in higher-performance aircraft?

From some of the threads I've read elsewhere, this seems to be one of the more contentious questions in aviation...

Nick


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PostPosted: Fri Nov 28, 2014 3:04 pm 
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Dudley has attacked that subject head on elsewhere on these forums. Remember that Pitch PLUS power equals performance. :)

I don't subscribe to either rigid school of thought because one can directly control pitch and power. The job is to use those two tools to influence the AoA, airspeed, vertical speed (performance).

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PostPosted: Fri Nov 28, 2014 3:25 pm 
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Thanks Oracle - I guess using pitch and power to put the aeroplane where I want it to be is something I do fairly instinctively in most cases. It just seems that on a fixed 3° glideslope it should be possible to maintain a more-or-less constant power setting and use very small pitch changes to control rate of descent. Things seem to have a habit of going pear-shaped for me in the last few hundred feet though...

Nick


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PostPosted: Fri Nov 28, 2014 4:25 pm 
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Oracle427 wrote:
Dudley has attacked that subject head on elsewhere on these forums. Remember that Pitch PLUS power equals performance. :)

I don't subscribe to either rigid school of thought because one can directly control pitch and power. The job is to use those two tools to influence the AoA, airspeed, vertical speed (performance).

All true, however...

On the ILS, I use pitch to maintain the glideslope & power to maintain airspeed. The airplane will respond quicker to pitch inputs to maintain GS, and the small deviations in airspeed can be handled using throttle.


Oracle427 wrote:
Yes, you are 100% correct Akar about flying the ILS to a landing. If the glideslope went out mid approach, going missed would be necessary as one isn't cleared for the localizer approach anyway.

If the LOC approach is part of the ILS chart and you get a "cleared ILS Runway such and such approach" you are cleared for the localizer approach. Example is your KMGJ ILS or LOC RWY 3. Lose the GS, and still legal to fly the LOC as long as you are not below the LOC MDA.

Whether or not "a good thing" is a matter for debate. I was taught to brief for both (and have both set up in NAV1 & NAV2).


AKar wrote:
I think all the missed approach procedures are laid out so that they can be flown from any point, and often your go-around speed is much different from final approach speed anyway, which would make at least my timings go difficult.

One needs to fly to the MAP hence needing a "fixed" approach speed from FAF to MAP and knowing that time e.g. that KMGJ ILS or LOC RWY 3. As Oracle mentioned, 90kias would be typical (and you should factor in winds for time).

One can climb early - but you are expected to fly to the MAP before executing the procedure.

Nick M wrote:
It just seems that on a fixed 3° glideslope it should be possible to maintain a more-or-less constant power setting and use very small pitch changes to control rate of descent.

Yes... why it is good to know beforehand (have memorized) power settings for various configurations / phases of flight for the approach. I think easy just to jump in the sim and go w/o knowing beforehand what these numbers are, then it can be a struggle to keep up with the approach.

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PostPosted: Fri Nov 28, 2014 4:41 pm 
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Great Ozzie wrote:
On the ILS, I use pitch to maintain the glideslope & power to maintain airspeed. The airplane will respond quicker to pitch inputs to maintain GS, and the small deviations in airspeed can be handled using throttle.

Thanks Rob - that's reassuring, as it's what I'm doing (or at least trying to do). Perhaps I just need to practice a lot and maybe consider investing in a different set of flight controls.

Cheers,
Nick


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