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Southport, Manitoba, Canada
Steve Pomroy is a professional flight instructor and aviation writer. He has been teaching since 1995 and holds an Airline Transport Pilot License, Class 1 Instructor and Aerobatic Instructor Ratings, military QFI, and an undergraduate degree in Mechanical Engineering. He's written and published three flight training books through his company, SkyWriters Publishing, and has several other books under development. Steve currently teaches RCAF pilot candidates on their Primary Flight Training course.

Monday, October 11, 2010

Fall Like a Leaf, Grasshopper

Today I went on a "Mutual Proficiency Flight" in the Grob. These flights are used here to keep instructors proficient without the instructor practice being obtained at the expense of the students. It’s an excellent program for several reasons, not the least of which is the fact that we can work on improving our own flying skills without worrying about students seeing us get it wrong. This is not about pride or ego, but about the fact that students are following our example, and if they see us do something wrong, there’s always the risk that that’s the example that will be followed.

One of the exercises we did was a "Falling Leaf Stall". The Falling Leaf is a maneuver in which we enter a stall and, rather than recover immediately (as we usually do), we remain in the stall for an extended period—often losing multiple thousands of feet of altitude. This gives us an opportunity to observe the symptoms of the stall for an extended period and to (try to) keep the wings level with rudder. Most aircraft are directionally unstable in the stall, so directional and roll control can be tricky, and ailerons are usually a no-no (“Why?” You ask? This is a topic for another post!). I wanted to do the Falling Leaf because I’m still very new to the Grob, and I’ve always considered the maneuver to be an excellent skill-building exercise.

Much to my chagrin, I didn’t do a very good job. I guess I didn’t do terrible, but mediocre would be a fair assessment. My training partner, Brandon, did a much better job. So, of course, I had to try a second attempt. It was an improvement, but still not as good as Brandon’s first try. In both of my attempts, I had to recover earlier than planned in order to avoid spinning—which, of course, is one of the points of the exercise!

During normal stall training, we recover from the stall either at the "first indication" (which, in practice, means before the stall), or immediately upon entering the stall. This makes a lot of sense, since the objective is to recover with a minimum loss of altitude. Why is this minimum loss of altitude so important? Stalls in the “real world” generally occur at low altitude. So they mandate a quick and effective recovery to prevent an unpleasant encounter with the ground (which, in case you can’t tell, is a euphemism for “crash”). So it makes sense to train the way we fly. A quick recovery in training will promote a quick recovery in the real world.

The problem with this quick recovery approach is that it limits our exposure to aircraft behavior in and around the stall. Why is this bad? Well, for at least two reasons: 1) The more exposure we have to stall symptoms, the better we are at recognizing an unplanned stall, and 2) Aircraft behavior (read “control response”) in the stall is usually very different than aircraft behavior out of the stall (I say "usually" because different aircraft types have different stall characteristics).

Point (1) is important because in order to recover from an inadvertent stall with minimum loss of altitude, we first have to recognize that we are stalled (or about to stall). Failure to recognize a stalled condition is just as bad as an inability to recover.

Point (2) is important because the vast majority of aircraft types require that we not use ailerons while stalled (and like I said above, this is a whole ’nother post). This is a hard habit to break since at all other times, we control roll with ailerons. Ask a flight instructor how difficult it is to get students to not use ailerons to correct for a wing-drop in a stall and they’ll tell you all about it. But find an instructor who uses the Falling Leaf, and you’ll probably hear a different story. The difference comes down to the oft-quoted mantra of "Practice Makes Perfect" (or, more correctly, "Proper Practice Makes Perfect"). More time spent in the stall, correcting correctly, leads to better directional corrections, even during the quick stalls that we normally train for.

It’s always struck me as odd that the Falling Leaf isn’t a required exercise for the training of pilots. In fact, I’ve met instructors who have never heard of the exercise. If you fly and you’ve never tried the Falling Leaf, go up with an instructor who is familiar with the exercise and try it out. If you’re an instructor and you’ve struggled with your student’s directional control during stall training, try the Falling Leaf exercise and see how things improve.

Happy Flying!

1 comment:

Anonymous said...

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