Conflicting info on Primary/Supporting IR scan ...

[Snakum]

Bad stuff happening as I start my IR for the third time.

I have my notes from IR training in 2001, and my notes from my instructor and the Rod Machado IR course don't match the ASA book (Complete Advanced Pilot) when studying the Primary/Supporting instruments for various flight conditions. So, I was wondering what you teach your IR students? Do you teach an expanded list of flight conditions (a la the ASA text), or just a minimal list (as reflected in the Gleim IR study guide and other IR texts)?

My notes list the following conditions and primary Pitch/Bank/Power scan, but is conflicted by the ASA manual for level turns and level offs, and the ASA text lists many more conditions:

Straight and Level ---------------- Alt-HI-ASI
Standard Rate Turn (IFR Turn) ---- Alt-TC-ASI
Constant Airspeed Climb/Descent -- ASI-HI-rpm
Constant Rate Climb/Descent ------ VSI-HI-ASI
Climb/Descent Entry (and TO) ----- AI-HI-rpm
Level Offs ------------------------ Alt-HI-ASI

I've also had a hard time calling a DG an 'HI'.

What/how do you guys teach this?

Minh

 

[IP076]

Its pretty easy the way I teach it....

Primary = Attitude Indicator/Tachometer/MP

Supporting = Everything else....

Otherwise known as "Control/Performance". The latest revision of the Instrument Flying Handbook talks a little about Control/Performance. Find an instructor that will teach you this concept of instrument flying, you'll be far better off in the long run.

 

[pilotmyf]

Don't get caught up in the primary/supporting details. Practice your scan enough and it will come automatically. I don't remember ever trying to remember a primary instrument in the soup.

 

[midlifeflyer]

There are two semi-competing theories on instrument flying.

Primary/Supporting which has received the FAA's blessing for many years and Control/Performance, which the FAA is first beginning to recognize, although the Air Force (which I assume knows something about flying) developed and has been teaching for years.

If you're doing pure primary/supporting for the purpose of the oral, you need to get the FAA Instrument Flying Handbook and treat it a the gospel. Of course it doesn't help that the current version as "softened" the text on this leaving it a bit greyer than before.

What are the precise differences you are seeing? For example you list
Level Offs ------------------------ Alt-HI-ASI
Technically correct since =after= you level off you are in straight and level flight, so the primary/supporting should be identical. But even the FAA's primary/supporting theory uses the Attitudfe Indicator as the primary instrument whenever you are making a change in pitch or bank. So, since the process of leveling off involves a pitch change the AH is primary for pitch until.

Primary/Supporting can be difficult, especially if it's seen as a bunch of stuff to memorize. But if you start with the basic idea that a primary instrument is the one that give the most accurate information about a particular flight condition, most of them actually fall into place. Even the "control/performance" people tend first to look to the FAA "primary" instrument when gauging the "performance" part of the equation.

That focus on "what am I trying to find out" also accounts for why you, for example, have two different ones for climbs and descents - while the airspeed indicator is primary for a constant =airspeed= climb, the VSI is primary for a constant =rate= climb.

Make any sense?

 

[Snakum]

Thanks Midlife ... that info clears up a lot. I was getting so confused.

If you're doing pure primary/supporting for the purpose of the oral, you need to get the FAA Instrument Flying Handbook and treat it a the gospel.

That's really what I'm driving at (haven't had my coffee yet). I need to be sure I understand exactly what the DE wants when he asks during the oral. As far as the Control/Performance theory, as taught in the ASA text, I think I can get a handle on that pretty quickly (it's new to me).

Can someone point me to a site with the FAA version for regurgitation during the oral?

Danke Schon ...

Minh

 

[JetBlast2000]

Snakum,
The concepts taught in either control/performance or primary/secondary will tremendously develop your instrument skills. These two concepts are not the same. It is important to incorporate and understand both. Here is a good article you might find useful.
http://www.avweb.com/news/airman/184208-1.html
Good luck.
JB2k

 

[Snakum]

That clears up a little more. I first learned the FAA-supported standard scan, and now studying for the IR after three years of rarely flying, I was tripped up when I hit this new-to-me concept and became confused.

Thanks JB2K ...

Minh

 

[Snakum]

More confusion ...

Question 4866 on Kip's IR Written Test Prep website states that the Primary and Supporting instrument, respectively, for a standard rate turn is the Attitude Indicator and the Turn Coordinator. The notes I have tell me the opposite is true, that the TC is primary and the AI is supporting. What's up?

Minh

 

[Jedi_Cheese]

Does it specify if it is entering a standard rate turn or when already in a standard rate turn?

 

[IP076]

That's where it all gets confusing.....You have to make sure whether you are talking about "entereing" or "Establised". The AI is usually the primary when "Entering" or "Transitioning" conditions.

 

[unreal]

Straight and Level ---------------- Alt-HI-ASI
Standard Rate Turn (IFR Turn) ---- Alt-TC-ASI
Constant Airspeed Climb/Descent -- ASI-HI-rpm
Constant Rate Climb/Descent ------ VSI-HI-ASI
Climb/Descent Entry (and TO) ----- AI-HI-rpm
Level Offs ------------------------ Alt-HI-ASI

I say forget all that noise.

Learn control/performance. Learn control/performance. Learn control/performance.

Instead of dealing with a complicated and difficult to learn scan, control/performance only deals with one basic rule: Pitch + Power = Performance. Just because you're in the soup doesn't mean that the rules of flying no longer apply. What do you do when you fly VFR? You look outside at the horizon and set a pitch attitude and power setting, right? It's the same way when you're on instruments. Take that big ol' natural horizon and shrink it into one instrument: your attitude indicator. Just like you did VFR, you're now going to set a pitch attitude on the instrument, and a power setting on your MP/tach. If you do this correctly, you will get predictable performance indicatons on your other gauges. Simple.

One of the best examples I've read that applies to instrument scans:

If you're flying straight-and-level in VMC using the natural horizon as a reference, what sense does it make to switch to Alt-HI-ASI when you enter a cloud?

 

[Cat Driver]

After fifty years of flying the things on instruments I have no idea of the scan I use, hmmmm ...maybe I don't scan at all, maybe I just get the whole picture and somehow the thing goes exactly where I want it to go.

Now if I were being graded on that method of flying instruments would I fail?

Even though the airplane did exactly what I wanted it to do?

Cat driver:

 

[bobbysamd]

Primary-Supporting v. Control-Performance

Its pretty easy the way I teach it....

Primary = Attitude Indicator/Tachometer/MP

Supporting = Everything else....

Otherwise known as "Control/Performance". The latest revision of the Instrument Flying Handbook talks a little about Control/Performance. Find an instructor that will teach you this concept of instrument flying, you'll be far better off in the long run.

Nice to see the FAA finally recognizing how one really flies on instruments, though the truth is you have to understand primary-supporting to help you fly control-performance.

Primary gives the most immediate information for a particular flight condition. Supporting backs up that information. E.g., primary for power will be the power instruments until the condition is stablized. Then, ASI becomes primary for power, because you obviously have the correct power set if you are achieving the airspeed you want. But, ASI is also supporting for pitch, because, if you have power set correctly but airspeed is incorrect, your pitch is not correct. Sure, it is confusing.

The FAA established primary-supporting as its method primarily it wanted you to assume that vacuum-powered gyro instrument failure. But primary-supporting is not how one really flies an airplane and how one flies jets. Control-performance is how it is done. Not only that; turbine equipment does not use vacuum-powered gyros.

I received a good education on control-performance as an Alitalia instructor at FlightSafety. The Alitalia training captains brought their program directly from Italy. They told us to train their students on control-performance because we were really teaching them to fly turbine equipment and not Cadets and Seminoles.

Look at it this way. Ever wonder why an AI is so huge on turbine equipment in comparison to lightplanes? It isn't so much sophistication or cost; it's because flying turbine equipment is dependent on setting up precise pitch and bank angles. The only way to establish a particular condition of flight in turbine equipment is by way of the AI and the power instruments (indeed, pitch + power = performance!). So, we learned to teach our Alitalia students to focus (not necessarily fixate or emphasize) on the AI after setting power and trim. Sure, they scanned the other instruments, but they flew the AI primarily.

I sold the concept essentially the same way as Unreal stated it, above. I told students to think of the AI as a small TV screen, with the blue of AI representing the sky and the darker part below representing the ground.

The neat thing about it is when we covered all the other six-pack instruments the students still held altitude and heading very accurately. After setting up precise positive or negative pitch, they flew rate climbs and decents very accurately. It was mind-blowing, actually.

So, what if vacuum failed? That was a non-issue because turbine equipment flight instruments are electrically-powered. We still had to give our Alitalia trainees enough partial panel to pass their instrument practicals.

Once more, control-performance is how you really fly the airplane on instruments. Primary-supporting enhances your understanding of the process (and what you must know to make your examiner happy!).

Note: Corrected comments about vacuum failure, see posts below.

 

[JAFI]

Bobbysamd brought up a good point. He said:

"So, what if vacuum failed? The answer is turbine equipment has enough backups so vacuum failure is a non-issue. "



Except that most turbine equipment does not use a vacuum system for the flight instruments. They have electric instruments. If the individual instruments fail there are flag(s) on the instrument so you know when it fails. On your vacuum system you never know if the instrument is working at 100%, 90%, 70%, or 0% until you back up with a more reliable instrument: example - Attitude indicator (in bank) with the turn and bank indicator and (in pitch) with the VSI and Altimeter - assuming normal cruse flight.



It is always important to back up "primary" instruments (vacuum or electric) with what ever you have. Any one who had an AI fail or partly fail in IMC can tell you how much fun that can be.


I cringe every time some one says that an AI is a primary instrument without also discussing cross checking with the other instruments to dertimine if or when it failed.


JAFI

 

[Cat Driver]

Many years ago when I flew bag runs I used to regularly cover up instruments and fly the trip that way just for practice, then when I would actually lose one it was a non event.

 

[bobbysamd]

Part 25 aircraft instruments

Bobbysamd brought up a good point. He said:

"So, what if vacuum failed? The answer is turbine equipment has enough backups so vacuum failure is a non-issue. "



Except that most turbine equipment does not use a vacuum system for the flight instruments. They have electric instruments . . .

That is absolutely correct. Sorry, I should have made that more clear in my original post.

Not only are turbine equipment flight instruments electrically-powered, I understand there are ways to switch data sources betwen panels meaning if the the captain's attitude instruments fail that data can be obtained from the FO's side. Finally, turbine aircraft have a third, smaller attitude indicator that is powered independently from the main panel(s).

Here again, my point was we were teaching our Alitalia students to be DC-9 and higher pilots, not Cessna and Piper pilots, so, hence, the emphasis on using the AI. We still taught them partial panel and gave them enough training to obtain their instrument ratings.