Tips for Tracking Courses

[HPNPilot1200]

I went out today and flew under the hood for about an hour with my CFI. Did pretty well but when tracking a VOR course, occasionally the HSI needle drifted a bit apparently due to the wind and I ended up more-or-less "chasing" the HSI needle rather than tracking a steady course with wind correction.

It was a bit turbulent, but I was wondering if anyone had some good tips that would help me track courses via navaids. I understand all of the concepts behind what I was doing and my CFI said it was all within limits, but I'm still trying to improve it.

Thanks,
Jason

 

[Henning]

I went out today and flew under the hood for about an hour with my CFI. Did pretty well but when tracking a VOR course, occasionally the HSI needle drifted a bit apparently due to the wind and I ended up more-or-less "chasing" the HSI needle rather than tracking a steady course with wind correction.

It was a bit turbulent, but I was wondering if anyone had some good tips that would help me track courses via navaids. I understand all of the concepts behind what I was doing and my CFI said it was all within limits, but I'm still trying to improve it.

Thanks,
Jason

Since you are using an HSI, you have the ability to use one of its great benefits. Just keep the lubberline over the tip of the HSI needle. If you find yourself going back and forth a lot, correct a few degrees into the direction you keep correcting for, the stronger the cross wind, the greater the correction you'll have to hold.

 

[Areeda]

I think this is a Ron Levy tip but I've adopted it.

The heading you want to find is the one that stops the needle movement. This will get you parallel to the track. This is more important than getting the needle centered.

Once you can stop the needle make a SMALL correction to get it moving slowly in the right direction. Be patient, if your a dot off it's not a big deal. When it centers take the correction out.

And I also use Henning's technique to intercept a course, works great.

Joe

 

[Sticky1]

Ok so it was either windy in the cabin moving that HSI thingy or the plane was moving.....either way....HSI "I rest my case"

 

[sheldon957]

And remember, while we are working so hard on this VOR training now to get our IFR ticket, it won't matter in the real world because in 2010 it almost all goes away! But I still have to study it now! That sucks a little in my book.

 

[poadeleted20]

I think this is a Ron Levy tip but I've adopted it. The heading you want to find is the one that stops the needle movement. This will get you parallel to the track. This is more important than getting the needle centered.

To be geometrically correct, you will not be parallel to track, but you will be converging with it at the destination (VOR radials being spokes of a wheel, not parallel tracks like a railway line). For the full treatise on the John McClain method of localizer tracking (which also works close in on VOR's, especially when holding at a VOR, but not well at all beyond about 5 miles), read on...

A lot of folks have trouble tracking the VOR/LOC needle, usually because they’re chasing it to an unnecessary degree trying to center it. The fact is that centering the needle, particularly on an approach to a station, is not absolutely necessary. It’s far more important to stabilize the needle, even if it’s a bit off center, than it is to have it in the center but swinging when you hit the missed approach point (MAP). I am indebted to long-time North Carolina Designated Examiner John McLain for this technique.

Let’s look at a typical VOR-on-the-field approach. We’ll say the VOR is halfway down the 6000-foot runway, and the MAP is at the end of the runway. Now, we all know we don’t want to break out right at the MAP, so let’s say that the critical point is about 1/2-mile short of the runway – far enough to let down comfortably from the MDA of, say, 400 AGL. Thus, the visual descent point (VDP) is 6000 feet from the VOR station.

Let’s say you’re chasing the needle left and right, with increasingly large oscillations. You hit the VDP with the needle swinging through the center but your heading 15 or 20 degrees off. If you think enough to look in the correct direction (remember, the nose is pointed 15 or 20 degrees away from the runway), maybe you see the runway. Even if you do, you’re heading away from the runway, and by the time you react and turn back, you’re on very short final and well off centerline. Not good.

On the other hand, let’s say you’ve got a half-scale deflection, but it’s rock steady. Where is your ground track going? RIGHT AT THE STATION – right where you want to go. Oh, so you’re worried about being off centerline? Well, just how far off are you? Half-scale is 5 degrees. One degree is one foot in 60, so 5 degrees is 5 feet in 60, so you’re 500 feet off to one side, 3000 feet from the runway end – about a 10-degree angle off, but headed straight for it. This is a piece of cake in a light plane. With a localizer, at decision height on an ILS, half scale is only 175 feet off, and again, headed straight for the runway.

So, what does this mean? We’re going to strive for a stable needle, even if it’s a bit off center. How do we do this? We use the needle movement, not the needle position, as a roll command. Very simply, if the needle is moving, we bank in the direction it’s moving, with angle of bank proportional to the speed it’s moving – slow movement, small bank; fast movement, larger bank (you’ll pick up the rate/angle correlation pretty quickly). When the needle stops, we level the wings, and keep them level until it moves again.

Once you’ve got the basics, you can start working on finer control by using this technique to make corrections to put the needle closer to center. If the needle is off to the right, roll into a right bank and hold the bank until the needle starts to move. Then roll wings level. The needle will continue to move left until you apply the original technique (needle moving left, bank left until it stops, then level the wings) to stop it. With a little practice, you’ll find this a very simple, natural technique.

You’ll notice the absence of one word you were probably expecting – “heading.” A lot of folks teach people to correct their heading by X degrees for Y amount of needle deflection, then try to compute in their heads a drift correction angle. Who cares? You’re not trying to compute the wind direction and velocity – you’re just trying to get to the end of the runway, and the one thing that will get you there is a stable needle. And winds change significantly between FAF and MAP, so what worked at 1500 AGL may be well off at 600 AGL.

Once you've got this down laterally, you can translate it into tracking the glideslope needle for ILS approaches, using pitch/power changes rather than bank angle changes. You'll find that using this technique produces a smoother, stabler, trip down final, and your passengers will appreciate it.

 

[midlifeflyer]

I went out today and flew under the hood for about an hour with my CFI. Did pretty well but when tracking a VOR course, occasionally the HSI needle drifted a bit apparently due to the wind and I ended up more-or-less "chasing" the HSI needle rather than tracking a steady course with wind correction.

Loved Ron's explanation of the McLain technique. Stability is king, and small corrections are the bearers of his throne.

...besides, the wind is usually not steady and the correction that worked at the FAF 8 NM from the runway may be completely useless 3 miles and 1500' lower.

 

[midlifeflyer]

And remember, while we are working so hard on this VOR training now to get our IFR ticket, it won't matter in the real world because in 2010 it almost all goes away! But I still have to study it now! That sucks a little in my book.

You really think that VORs and localizers are going away in 3 years? Or that the same technique of keeping a stable needle and flying a relatively stable course or track don't apply to a GPS approach?

Interesting...

 

[HPNPilot1200]

Thanks for all the advice, folks. It seems to me that there is a general consensus that trying to keep the needle steady is relatively more important than keeping it exactly centered.

I'll try putting these techniques to practice the next time I fly.

Thanks,

 

[tonycondon]

Yea Jason that technique that Ron describes is how I (now) teach all my IR students and how I fly instruments. Its great!

Oh I love the sky is falling crowd about navaids getting phased out. 5 years ago when I started training everyone said that all the NDBs will be gone in 5 years. I learned to master them at my school as there was an NDB approach to home that actually had lower mins than the VOR approach to that runway. Well if you look through the approach plates for Iowa, and throw out all the GPS plates, you darn well better have an ADF in the plane if you want to get into about half (or more) of the airports in the state. They are slowly phasing out but im not getting too excited.

 

[midlifeflyer]

Thanks for all the advice, folks. It seems to me that there is a general consensus that trying to keep the needle steady is relatively more important than keeping it exactly centered.,

Yes but... Be aware that your CFII and ultimately your DPE may be looking for a more-or-less centered needle. Even Ron's description goes into how to ultimately center the needle.

I think that putting the idea of stability being a top priority is to prevent the single most common error among instrument students and new instrument pilots - the tendency to over-correct, which results in chasing the needle. If you look at the latter part of Ron's explanation, returning to center isn't a matter of making a sharp turn toward the needle -with the excellent chance of blowing through it to the other side, a chance that increases as you get closer to the station - but of making a turn that simply gets the needle started moving in the correct direction and waiting for it to come in the rest of the way.

Question - have you flown an approach yet =without= the hood? That is one of the four most effective ways to see for yourself how little correction is really needed. The other 3 are to watch another student fly so that you can see them overcorrect, have your CFI fly under the hood while you watch, and watch an autopilot.

 

[gismo]

Yes but... Be aware that your CFII and ultimately your DPE may be looking for a more-or-less centered needle. Even Ron's description goes into how to ultimately center the needle.

I disagree. What the DPE is going to be looking for on a PPL practical isn't a needle in the donut, it's the ability to track towards or from a VOR without big swings in the heading.

I think that putting the idea of stability being a top priority is to prevent the single most common error among instrument students and new instrument pilots - the tendency to over-correct, which results in chasing the needle. If you look at the latter part of Ron's explanation, returning to center isn't a matter of making a sharp turn toward the needle -with the excellent chance of blowing through it to the other side, a chance that increases as you get closer to the station - but of making a turn that simply gets the needle started moving in the correct direction and waiting for it to come in the rest of the way.

Question - have you flown an approach yet =without= the hood? That is one of the four most effective ways to see for yourself how little correction is really needed. The other 3 are to watch another student fly so that you can see them overcorrect, have your CFI fly under the hood while you watch, and watch an autopilot.

You're last question make me suspect you think Jason is working on his instrument rating, but AFaIK he's training for a PPL at this time. Last time I checked, instrument approaches (with or without a hood) weren't part of the PPL syllabus.

 

[tonycondon]

I disagree. What the DPE is going to be looking for on a PPL practical isn't a needle in the donut, it's the ability to track towards or from a VOR without big swings in the heading.

You're last question make me suspect you think Jason is working on his instrument rating, but AFaIK he's training for a PPL at this time. Last time I checked, instrument approaches (with or without a hood) weren't part of the PPL syllabus.

check and check. Jason is going to be a Private Pilot on his 17th birthday next month. He has pretty high personal standards for his knowledge and flying, and I think he'll be ready for an instrument knowledge and practical test pretty soon after getting his private.

 

[HPNPilot1200]

Question - have you flown an approach yet =without= the hood? That is one of the four most effective ways to see for yourself how little correction is really needed. The other 3 are to watch another student fly so that you can see them overcorrect, have your CFI fly under the hood while you watch, and watch an autopilot.

I've flown approaches both with and without the hood and in actual conditions; all were great learning experiences. What I meant by the statement in my earlier post was similar to how you interpreted it, keeping the needle steady is of high priority in addition to making very minor corrections to center the needle.

I disagree. What the DPE is going to be looking for on a PPL practical isn't a needle in the donut, it's the ability to track towards or from a VOR without big swings in the heading.

You're last question make me suspect you think Jason is working on his instrument rating, but AFaIK he's training for a PPL at this time. Last time I checked, instrument approaches (with or without a hood) weren't part of the PPL syllabus.

Your correct, I'm not going for my instrument checkride yet but I'm close to my private checkride and starting to put the knowledge of instrument flying I've acquired to practical use. I definitely appreciate everyone's input.

As Tony alluded to, I do tend to hold high personal standards for myself when it comes to flying, so challenging myself with learning the finer points of instrument flying is certainly high on my list of to-do's.

 

[gismo]

I've flown approaches both with and without the hood and in actual conditions; all were great learning experiences. What I meant by the statement in my earlier post was similar to how you interpreted it, keeping the needle steady is of high priority in addition to making very minor corrections to center the needle.

The key is to stop it first, then center it slowly. This is pretty much true of any variable you are trying to control, from airspeed to the glideslope indicator. Once you have the needle stopped there's no big hurry to center it but eventually you must or the errors will accumulate. You also must understand that the needle will wander even if you are locked onto the center of the radial, the signal itself varies along the path.

Your correct, I'm not going for my instrument checkride yet but I'm close to my private checkride and starting to put the knowledge of instrument flying I've acquired to practical use. I definitely appreciate everyone's input.

As Tony alluded to, I do tend to hold high personal standards for myself when it comes to flying, so challenging myself with learning the finer points of instrument flying is certainly high on my list of to-do's.

Nothing wrong with that! Of course it will likely be a lifelong pursuit (I'm still working on it).

 

[poadeleted20]

While your instructor may be looking for a more professional performance, what the examiner should be looking for is that the applicant "(a)llows, while on the final approach segment, no more than a three-quarter-scale deflection of the CDI or within 10° in case of an RMI, and maintains airspeed within +/-10 knots of that desired." (IR-A PTS, Area VI, Task A, Objective 12). Of course, the examiner is also looking to see that you "demonstrate mastery of the aircraft with the successful outcome of each TASK performed never seriously in doubt." Too much s-turning, even within 3/4-scale, might be deemed failure to demonstrate mastery of the aircraft. That's why stabilizing the needle, even if it's somewhat out of center, is key for passing the practical test. Just make sure you learn how to keep it both stable and inside the doughnut before you go for your airline interview simulator ride.

 

[mantakos]

... no more than a three-quarter-scale deflection of the CDI...

One thing I've always wondered about is "but, but, what about when the FAF is a VOR? Am I expected to be able to do a passage over a VOR without ever exceeding 3/4 scale deflection?"

I got pink-slipped on my first attempt at the IR checkride by beginning my descent to MDA after passing the FAF, which was a VOR, while the needle was still pegged from station passage. The passage over the VOR inbound on final was at the completion of a HILPT. I was stable and pretty close to the VOR when I passed over it inbound on final, but far enough off course, that the needle was pegged for a short time after passage, but "came back" a few seconds later. The DPE said I shouldn't have begun to descend on final until the needle was centered again. I could see his point, but was never particularly clear on how this situation applied to the PTS.
-harry

 

[midlifeflyer]

You're last question make me suspect you think Jason is working on his instrument rating, but AFaIK he's training for a PPL at this time. Last time I checked, instrument approaches (with or without a hood) weren't part of the PPL syllabus.

Ahhh... I guess the question being in the "Cleared for the Approach" part of the forum confused me.

But that presents another issue. Off-center for an approach results in the small numbers Ron talked about, but those numbers get much larger the further away we get from the station - a typical VFR scenario. So, 1/2 deflection when 30 miles away translates to miles off course, not mere hundreds of feet.

 

[HPNPilot1200]

Ahhh... I guess the question being in the "Cleared for the Approach" part of the forum confused me.

I figured it would be most appropriate to put it in the "Cleared for the Approach" category since it relates to instrument flying.

 

[poadeleted20]

One thing I've always wondered about is "but, but, what about when the FAF is a VOR? Am I expected to be able to do a passage over a VOR without ever exceeding 3/4 scale deflection?"

Obviously, that's not possible -- in the cone of confusion, the needle can do just about anything.

I got pink-slipped on my first attempt at the IR checkride by beginning my descent to MDA after passing the FAF, which was a VOR, while the needle was still pegged from station passage. The passage over the VOR inbound on final was at the completion of a HILPT. I was stable and pretty close to the VOR when I passed over it inbound on final, but far enough off course, that the needle was pegged for a short time after passage, but "came back" a few seconds later. The DPE said I shouldn't have begun to descend on final until the needle was centered again. I could see his point, but was never particularly clear on how this situation applied to the PTS.

I agree with the DPE -- no descent until the needle is stabilized on the other side. Otherwise, a strong wind might blow you off to the point that you're out of the protected area while waiting too long for the needle to come back. However, I would say no bust for the needle being off while passing the station as long as you reintercept and have it back in tolerance before stepping down.

 

[gismo]

Ahhh... I guess the question being in the "Cleared for the Approach" part of the forum confused me.

But that presents another issue. Off-center for an approach results in the small numbers Ron talked about, but those numbers get much larger the further away we get from the station - a typical VFR scenario. So, 1/2 deflection when 30 miles away translates to miles off course, not mere hundreds of feet.

30 miles and half deflection would be about 2.5 miles from the centerline. Fortunately airways are wider than that and in any case staying closer to the radial centerline is much easier at 30 miles out than when close in.

 

[tonycondon]

Obviously, that's not possible -- in the cone of confusion, the needle can do just about anything.

I agree with the DPE -- no descent until the needle is stabilized on the other side. Otherwise, a strong wind might blow you off to the point that you're out of the protected area while waiting too long for the needle to come back. However, I would say no bust for the needle being off while passing the station as long as you reintercept and have it back in tolerance before stepping down.

while i cant argue with your method described, i have trouble imagining the atmospheric phenomenon that would need to be present to blow you off course while passing the cone of confusion. i usually teach to get stabilized on the inbound course before station passage, and then as you get close, hold the heading that kept the needle, and then wait to come out the other end. But i dont suppose it would take much more time (distance) to get a positive reading on the needle and sure would bring some peace of mind.

 

[gismo]

while i cant argue with your method described, i have trouble imagining the atmospheric phenomenon that would need to be present to blow you off course while passing the cone of confusion.

I suspect it's more an issue of poor tracking into the "cone of silence" leaving the plane off to one side and heading further off course as you approach and pass the VOR (BTDT). I'm pretty sure that if you were within half a dot a mile out and tracking well, holding the heading will keep you in protected airspace for at least a couple miles on the other side. But if you start out passing the VIR off course and on the wrong heading, the zone of confusion can get pretty big.

 

[poadeleted20]

I guess the point is that if the needle isn't within the scaled range, you can't tell with reasonsable certainty whether you're still in the cone of confusion or unacceptably off course beyond it; thus, the admonition not to descend until the needle is back in range after station passage.