Partial Panel

[Mike H]

That's a lot of blame. Unfortunately it's accurate. The emphasis seems to change periodically. When I did my instrument training, the focus was on compass turns and they were almost second nature. Timed turns were more difficult to me and I never really learned them until I needed to for my CFI-I, but which time the emphasis changed.

Both methods have their issues but they really should be given equal, um, time, when being taught.

How about the "Just get it close and then keep making small corrections as needed- and they will be needed" method?

 

[mshunter]

I don't. Doing timed turns compass errors are not really a consideration. It may not be very accurate but then neither are doing compass turns.

No, but turn coridinator errors are a big one. I can't tell you how many times I've seen a turn cordinator be off by as much as 15 seconds in a 360 turn. Learn how to use UNOS to your advantage and you'll never have a proble with it. I used to teach both ways, with an emphasis on compass turns. The TC is more of a crutch than anything. The Lear I fly in doesn't even have a turn coridinator. But if you loose you insts. in something like that, you can preatty muc figure your screwed anyways.

 

[MidlifeFlyer]

How about the "Just get it close and then keep making small corrections as needed- and they will be needed" method?

Of course, that's the whole idea - get close and the correct. But doing wither correctly will get you closer than not doing them correctly. And if you're doing compass turns at a area where you need 40° lead or lag to account for both compass error and lead in a turn to the north in a 172, and don't understand how it works, you're not getting close.

Might as well say that if you really want to get "close" how about turning to the HSI page of your handheld GPS - you won't even realize you're on partial panel.

 

[intern_mike]

Before incorporating all the ANDS and UNOS rules, teach turning AWAY from what looks right. My CFI was always impressed with my compass turns, and I would just tell him that I turn the opposite of what looks correct.

Here is some homework you can assign as well:

Magnetic Compass
Homework Reading Assignment

Required Reading
Instrument Flying Handbook 3-9 to 3-13

Jeppesen Instrument/Commercial Manual – “Magnetic Compass” 2-12 to 2-15


Magnetic Compass Quiz

1. How is the magnetic compass constructed? ________________________________________________
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2. Why does the compass “read” backwards? i.e., on the compass above, we would turn to the right to get
to an East heading which is depicted to the left of our current heading ___________________________
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3. What is the basic operating principle of the magnetic compass? ________________________________
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4. What are the limitations and errors of the magnetic compass? _________________________________
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5. What is the basic principle behind the magnetic dip errors? ____________________________________
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6. Why does deviation occur? _____________________________________________________________
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7. Why does variation occur? _____________________________________________________________
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8. How can we remember the errors of the compass? (think about acronyms, etc.) ___________________
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[The Gardener]

All timed. I have my students break it down. 2 minutes for 360, 1 min for 180, 30 seconds for 90 and 15 seconds for 45. At the very basic 3 degrees/second, or 10 degrees in 3 seconds.

If on a heading of 360 and asked to turn right to 120 that is a 90 degree turn and a 45 degree turn (or there abouts) so that's about 45 seconds of turn. Once that is done I have the students correct the error.

I know it sounds complicated but it really isn't and it's really easy if you have an adf to look at and get a idea of how many degrees away your heading is.

:dunno: 120/3=40. Seems easy enough to me and it has always worked well.

I teach both compass and timed turns. They both have their place. Doing a couple of full 360 turns while your student watches the compass/HI at the same point really hammers home all the theory of the compass errors. Seeing it is believing it.

 

[Mike H]

Might as well say that if you really want to get "close" how about turning to the HSI page of your handheld GPS - you won't even realize you're on partial panel.

As long as I have the moving map, I hardly ever look at the panel anyway

 

[poser765]

:dunno: 120/3=40. Seems easy enough to me and it has always worked well.

I teach both compass and timed turns. They both have their place. Doing a couple of full 360 turns while your student watches the compass/HI at the same point really hammers home all the theory of the compass errors. Seeing it is believing it.

I've noticed "mathing" abilities start going down when getting loaded up partial panel on an approach. The way I usually do it requires almost no math and I can eyeball it in half a second looking at an OBS or ADF.

 

[shdw]

I'd add a drawing to this, since I can't do it on the computer I'll just explain:

Draw a circle on a piece of paper, mark the north, east, south, and west portions. Next make the following notations:

• Above north put +30, below south put -30.
  
• At headings 30 and 330 put +20.
  
• At headings 60 and 300 put +10.
  
• At east and west put 0.
  
• At headings 120 and 240 put -10.
  
• At headings 150 and 210 put -20.

Using this model I then explain how to know where to roll out when making compass turns. It takes about a half an hour to explain with sufficient examples and one flight to master.

Example Questions:

Q:Turning to heading 330, from heading 270, what heading would you roll out on?

A: 350 because we must overshoot by 20 degrees when turning to a heading of 330.



Q: Turning to heading 030 from heading 090, what heading would you roll out on?

A: 010 because we must overshoot by 20 degrees when turning to 030. This question often yields the result 050 because the student forgets that, when turning left, our heading number is constantly decreasing. Therefore, an overshoot would involve a subtraction of 20 instead of an addition of 20.



Q: Turning to a heading of 225 from 090, what heading would you roll out on?

A: Since 225 is half way between 210 and 240, we know we must undershoot by 15 degrees. Our rollout will be at 210.



Q: Turning to heading 180 from 270, what heading would you roll out on?

A: 210. For the same reasons as answer 2, students will often answer this with 150.


As you may have notice, the plus and minus in this model doesn't depict an actual mathematical addition or subtraction. Instead, it depicts overshooting or undershooting when turning to a heading. You must intuitively determine which heading you must roll out on based on the heading you're at and the heading you're turning to.

 

[subpilot]

I'd add a drawing to this, since I can't do it on the computer I'll just explain:

Draw a circle on a piece of paper, mark the north, east, south, and west portions. Next make the following notations:

• Above north put +30, below south put -30.
  
• At headings 30 and 330 put +20.
  
• At headings 60 and 300 put +10.
  
• At east and west put 0.
  
• At headings 120 and 240 put -10.
  
• At headings 150 and 210 put -20.

Using this model I then explain how to know where to roll out when making compass turns. It takes about a half an hour to explain with sufficient examples and one flight to master.

Example Questions:

Q:Turning to heading 330, from heading 270, what heading would you roll out on?

A: 350 because we must overshoot by 20 degrees when turning to a heading of 330.



Q: Turning to heading 030 from heading 090, what heading would you roll out on?

A: 010 because we must overshoot by 20 degrees when turning to 030. This question often yields the result 050 because the student forgets that, when turning left, our heading number is constantly decreasing. Therefore, an overshoot would involve a subtraction of 20 instead of an addition of 20.



Q: Turning to a heading of 225 from 090, what heading would you roll out on?

A: Since 225 is half way between 210 and 240, we know we must undershoot by 15 degrees. Our rollout will be at 210.



Q: Turning to heading 180 from 270, what heading would you roll out on?

A: 210. For the same reasons as answer 2, students will often answer this with 150.


As you may have notice, the plus and minus in this model doesn't depict an actual mathematical addition or subtraction. Instead, it depicts overshooting or undershooting when turning to a heading. You must intuitively determine which heading you must roll out on based on the heading you're at and the heading you're turning to.

You got it all backwards... it is UNOS (Undershoot North, Overshoot South).

 

[Mike H]

you're gonna do all that mental math while you're partial panel in actual IMC?

You ought to be able to get within 20 degrees without compensating at all.

 

[subpilot]

you're gonna do all that mental math while you're partial panel in actual IMC?

You ought to be able to get within 20 degrees without compensating at all.

It's really not that hard. No harder than figuring out how many seconds you have to turn for and then remembering to start the time and then keep watching the time so that you don't overshoot all while verifying your still coordinated standard rate so that you are not ahead or behind on the turn.

Just take 15 minutes sometime to practice this and you will have it down (I taught this to my students using a flight sim program before going in the air).