Much time is spent in the book describing what makes flying so different and challenging compared to ground based activities.
We spend most of our lives anchored to the ground in one way or another. In fact, to say someone is “well grounded” or that he or she “has their feet on the ground”, is generally considered a compliment.
But all that time spent on the surface may make it difficult to shift gears when the wheels of a plane leave the ground. It takes a while to adjust and to understand, and even experienced pilots can slip up from time to time.
It has to do with frames of reference. One is the ground. We think of it as stationary, but standing on the surface of the planet you may be moving up to about 1,000 mph, depending on your latitude. But if you know how to juggle, you don’t have to factor in the speed at which you’re moving - relative to the surface you’re stationary, and that’s all that matters. Similarly, if you’re juggling on a moving train - since your frame of reference is now the train, no allowance for its movement need be made.
The essence is that, once in the air, the plane has zero reference to the ground as far as flight characteristics go. Your frame of reference now becomes the air mass in which you are moving. The implication is that a steady wind has no effect on the plane, other than its path over the ground. The plane is simply flying in an air mass which is itself moving. Disregarding gusts and shear, once a plane is in the air, like a free balloon, there is no wind.
I wish to clarify what I mean when I call something a “Stick and Rudder Moment”. A pilot will do or say something where a lightbulb goes off in my head and I suspect they may not be adequately making the transition from ground-based to flight-based thinking. The upside is that it can often become a "teachable moment".
Here are some examples I’ve come across, and I’m sure you guys can come up with many more.
1) The “Dreaded Downwind Turn”.
This is the grandaddy of "Stick and Rudder Moments". Many pilots believe that the turn from crosswind to downwind is especially dangerous. Why? The plane may stall as it is picking up a tailwind during the turn, putting it closer to the stall.
Such is not the case. If planes do tend to stall there, it is due to the illusion of increased speed leading them to slow down too much or not realize speed is decaying. There is no “wind” pushing against the rear of the plane, causing it to stall.
2) A fellow on the Cirrus Owner’s site observed that a quartering tailwind seemed to push his plane ahead by more than the wind velocity. For example, he’d be flying along with a TAS of 190k and a quartering tailwind of 10k and find his groundspeed being greater than the combination of 190+10. He figured it was like a sailboat “tacking”, and that some sort of trigonometry was letting the quartering tailwind “squeeze” his plane forward faster than the wind velocity.
The thread (“Winds?”) went on for hundreds of posts with other pilots and instructors trying every imaginable explanation and analogy to show him the error of his reasoning. I don’t know if we ever did, and the same theme was continued in another thread by the same fellow. But it was a fun, if somewhat aggravating ride.
3) Flying a demo Cirrus northbound it FL, I noticed on autopilot it was flying slightly right wing down. I mentioned it to the demo pilot, who opined that it was probably just the autopilot correcting for the right crosswind.
4) A pilot posted that when he approached in a crab with a crosswind from a certain direction, he could feel it in his prop.
5) I’ve heard it said cowl flaps are especially useful when flying downwind, when cooling would otherwise be compromised by the tailwind.
6) Someone suggested in a strong enough wind, a plane that was not tied down could eventually just hover.
7) Many have expressed that banking the airplane may cause fuel to flow unevenly from wing tanks. When queried, they were not referring to uncoordinated flight.
"8) And, of course, there was the suggestion to use an iPad app’s speed readout as an aid when landing.
One thought exercise is to imagine that you’re flying a plane capable of 50k slow flight in a 50k wind. Start directly into the wind with a zero groundspeed. Then start doing 360’s. With each 360 your groundspeed goes from zero to 100k and back to zero. Imagine how that will feel as you speed up to 100k only to slow back down to zero. How will that feel? How will that sound? You surely will be able to tell when you’re upwind and when you’re downwind, right? The answer is so nonintuitive that you might not believe it, but its true. Try it some time under the hood and the answer will be clear - though not what you might think.
Anyway, let me open the floor to discussions of any of the above, or feel free to add your own “Stick and Rudder Moments".
Note: I also posted this to ctflier.com, since not everyone there frequents this site. I may also post it to PilotsofAmerica.
