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Hint # 2 was a mental exercise that can and should be mastered on the ground for the computation of headings, which should be second nature. .
Hint # 3 now get's to the essence of aircraft control.
Any of you who have gone through flight training will remember your instructor badgering you about "overcorrecting". i.e. your turns are too fast, your banks are too steep, your intercept angles are too large, etc. .
This hint is what that is all about.
.The heading tolerance for a Private ticket is + or - 20 degrees. For an Instrument rating the heading tolerance is + or - 10 degrees. .
Unfortunately, because these tolerances are so large, there is an acceptance that they are normal, and this in turn leads to a sort of complacency, which detracts from precise flying (and control) and which in turn, unfortunately adds considerably to the cost of your flying -- instructions while you are learning -- and the time and fuel it takes when you are trying to go somewhere. It's a tolerable degree of sloppiness. There is an easier and better way with NO SLOP..
I had this brought home to me, in exactly how much difference it made in fuel consumption, right after I learned this little trick from an airline captain, who was working with me on an instrument rating.
The flight from Charlottesville to Fort Lauderdale in a Mooney Super 21 usually required a stop for gas at Melbourne. However, on the trip back, I was able to go from Fort Lauderdale to over Danville ON 26 GALLONS, consuming 5.98 GPH rather than the usual 8. Thus I was able to make it back home with 20 Gallons in reserve (3 + hours, rather than having to make a fuel stop. Winds were otherwise the same as going down (45 degrees from the west). . .
What made all the difference?
Two things.
Heading control and altitude control.
At that point, I was as sharp as I have ever been, having had a considerable amount of practice under someone who expected a tolerance of + or - 1 degree in heading control, and expected the altitudes to be held exactly. .
I had over 1000 hours at the time, and was taught this simple lesson in how to maintain headings precisely, hour after hour. It gave me additional time to pay attention to altitude, and the rest of the flight. .
I started teaching it to students and they were able to quickly master precise heading control also. .
What follows is this neat little trick.
On the attitude indicator (Artificial Horizon), at the top (12:OO position) is an index mark. On the outside of of the indicator are other index marks indicating 5,10,15,30,45,60 and 90 degree bank angles. .
Underneath the indicator is another index that rotates around the horizon and marks off what the actual bank is at the moment. .
The SECRET to accurate heading control is two parts.
1. Compute the heading you are going to fly and announce it. (To yourself anyway). (Hint 2)
2. Turn to the heading and MAINTAIN it. (Hint 3)
The "maintain it" portion is where the sloppiness costs time and money, because the normal tolerance (10 to 20 degrees) is far more than necessary.
.The SECRET to maintaining the heading within + or -1 degree is matching the indexes at the 12:00 position. When a course correction has to be made, a correction of 1 degree can easily be made by a turn with a degree of bank, HALF the THICKNESS of the index. (The index on most horizons is about 1/8 inch wide at the top so the indicator moves about 1/16th of an inch, barely enough to notice. It's enough to turn the plane leisurely, but give you very precise control). .
What happens is that the turn is very slow, so you can easily stop the turn by leveling the wings. Nothing happens very fast, at this very slow rate of turn, so you can be doing the rest of the instrument scan, communications, navigation, while making these small course corrections. .
Thus, when you are flying a heading, you should be constantly making 1 degree corrections, rather than larger ones, and "nudging" things back to the desired heading, rather than taking larger cuts at it. When you allow things to get off more than 1-2 degrees, you then have a tendency to make larger angles of bank which in turn makes things happen faster, so you overshoot or undershoot your desired heading, instead of turning exactly where you want to go and stopping. This also takes lots more fuel (energy). .
The normal instability of the airplane, plus the scalloping of VOR Radials, etc will always cause a constant need for small corrections. You really don't fly in a straight line, rather you fly on a course that continually, oscillates from one side to the other and up and down.
The objective is to keep the corrections as small as possible to conserve energy. If 20 degrees is acceptable tolerance, then that is what you get accustomed to. When 10 degrees becomes the standard, then that is what you get accustomed to. .
You can just as easily get accustomed to a 1 degree tolerance. . (and get 25% better gas mileage without buying some gadget)
It takes considerably less mental energy and effort to fly with a 1 degree tolerance than it does with 10 or 20 degrees of slack. It is also more fuel efficient. The airplane is much easier to control, headings are easier to maintain, and it requires less continuous thought. .
This ability to make a 1 degree correction does a couple of things for the controllability of the airplane. It gives you more time to spend on navigating, communications, etc. Because the plane is turning slower, it doesn't have time to get off heading, when you are distracted by something else.
It also takes less energy to get the plane back on course when a correction needs to be made. Thus, it conserves fuel and increases real speed. The example I stated previously shows how much difference it can make in your fuel burn.
When you get into using this technique for instrument approaches, it makes life easier also, again because things don't happen so fast, at a time when you really have your hands full. .
If you have questions you may E-Mail me at
atpcfii@ferrypilot.cjb.net
Fred H. Quarles ATP-CFII
804-293-8457
- End of Hint # 3 -
