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Have you tried a forward slip lately?
There was someone who never gave me any good advice except just one time. On that occasion, she admonished me to never tell a student that something was easy.
“It may be easy for YOU,” she warned, “but it may not be easy for them and your description of it as “easy” will only serve to annoy them.”
For once she was right. It was a rare event… she also tried to fly my Cub through the hangar at Madras… but that’s a different story.
I’m often tempted to tell someone that a particular operation is easy but find myself remembering that advice and so I stifle myself. I had an experience the other day that was a good example. We were introducing my favorite technique of entering the forward slip in the turn from base to final. I realized that this maneuver is “easy” in terms of how I teach it. It may be difficult, however, in the actual execution. And THAT is one of the great truths in flight instruction: Many pilot operations really are easy in description. It’s the execution of them that is difficult until we practice.
The forward slip is certainly one of them. But, like so many things, we often make something that is relatively simple, very complex and difficult when we approach it the wrong way. Let me give you an example that really sticks in my mind. I was giving flight instruction to a rated pilot. We were in the pattern for Sunriver’s runway one-eight. That’s a right hand pattern. As my student turned the corner to right base, it was obvious that he was high. As I usually do, I said, “are you high or low?” He replied that he was high, so I immediately said, “I’d go ahead and put flaps on, but you’re going to need to enter a slip as well. This is the time to do it while you’re turning from base to final. “
The guy was in the turn from right base to right final. His right wing was already down. All he had to do was apply left rudder and continue to use aileron to manage the turn. Easy, right? But, like most pilots, he was accustomed to lowering his LEFT wing in a forward slip and that’s exactly what he attempted to do. I’ve since figured out that the maneuver he attempted is actually what the aerobatic folks refer to as an “outside” maneuver and not really something you should attempt in a decrepit old Cessna 140. I had instructed him to do something that in theory was very easy. But in his execution he had turned it into something that only someone of Patty Wagstaff’s abilities should attempt.
The forward slip is an important descent-steepening maneuver that every competent pilot should be able to perform with EITHER wing down. Most pilots don’t enter it until on final. Since they are not turning, they can lower either wing and since they sit on the left side of side by side airplanes, they always lower the left wing. They don’t know how to do it any other way. Here’s how I teach it. It’s the EASY way.
(My attorney advises me to tell you this: If you haven’t had spin training, don’t do this. Just continue to fly a stabilized approach and forget about the forward slip. Take up Bridge.)
First of all, if we wait until we’re on final, it may be too late for the slip to put us back on the appropriate glide slope. The forward slip usually needs to be entered sooner and that’s why it’s easy. We take advantage of the fact that we are already in a turn. In that turn from base to final, we’re in the ideal position to judge whether we are high or low AND we have already performed half of the forward slip entry… we’ve put a wing down in order to be in that turn. So all we have to do is apply opposite rudder. Bingo, you’re in a slip. Now let’s perfect it. When we put that rudder in, a couple of undesirable things will happen: The rudder input will cause our bank to lesson unless we apply more aileron. That rudder input will also cause our course in the turn to change. That’s EASY to fix. Just remember that in a landing approach, rudder controls heading and aileron controls course. In this case, we really don’t care about heading. In the words of one of my favorite instructors, “it is what it is”. What’s important is COURSE. We need to maintain that circular course that will take us around the turn from base to final AND that will intercept the center line AND keep us on it. Aileron will do that. By remembering what these two control surfaces do, the pilot makes the maneuver EASY.
To practice the forward slip entry, simply go to altitude, preferably over countryside with lots of section lines. Those lines will allow you to fly an accurate course line. Use a low cruise power setting. When practicing slips, it’s not necessary to be in a descent which will cause you to have to climb again. The use of power will help conserve altitude and allow you to practice on and on and on. Align yourself with a set of lines and then start a turn. By watching the section lines, it’ll be easy to see when you’re halfway through that ninety degree turn. At that point apply opposite rudder. Don’t be timid. Get on it. Use aileron to maintain the bank AND the turn. Stop the turn when you’ve completed ninety degrees of turn and maintain that forward slip. Don’t pay any attention to altitude… you’ll probably lose some since the airplane is so dirty. Now that you’ve done one slip entry in a turn, simply kick out of the slip for a moment and then start a turn the other direction and practice another slip entry in that direction. If you master these alternating forward slips, you’ll be “slip-proficient”.
I find that most of the pilots who come to me for instruction know how to forward slip. They just can’t do it both ways and they can’t enter it from a turn. That’s where education and practice come in.
Now, just one more little piece of what serves as intelligence from the right seat: Most pilots kick out of the forward slip when at “the bottom of the hill”, when they start the round out to flare for landing. That’s understandable… they don’t want to risk touching down while in a slip. BUT… they are usually a little fast when they reach that point and by kicking out of the slip, they clean the plane up and cause it to float even further. Perhaps they need to consider leaving the plane in a slip which will cause it to decelerate even sooner. After all, the forward slip performs its job of steepening the glide without increasing the speed because it presents the side of the plane to the relative wind which creates drag. That condition will also serve the pilot if he would like to slow the plane down during the roundout and flare. I’ve only had one student inadvertently touch down while in the forward slip and it wasn’t that big a deal because we were on grass.
If you get good at slips, not only will you be able to better control the accuracy of your approaches, but you will also become even more proficient in the use of stick and rudder and that’s what it’s all about, isn’t it?