Airplane Landing: Cotter-Pin Approach

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The opposite of this procedure occurs when the pilot starts the turn to final approach too late, tries to utilize the normal bank, and proceeds to complete what I call the cotter-pin approach. He overshoots the runway centerline and then has to steepen the bank beyond safe limits in order to turn back to intercept the runway centerline. Viewed from above, it looks like a cotter pin. And it can become very dangerous very quickly.

A seemingly harmless item like turning from base leg to final approach too late catches the unwary pilot in a situation of deteriorating control command, increasing bank and stall speed, and decreasing airspeed. If I ever wanted a recipe for a potential disaster, this would be it. And the innocent thinking of the unknowing pilot goes something like this:

“Oops, I turned too late—guess I’ll just steepen my bank a little and get back on final to the runway. I remember my instructor told me as long as I didn’t exceed 30 degrees of bank in the pattern, I’d be okay.”

“Wait a minute, this still isn’t getting it. I’m not turning fast enough to line up. I bet if I add just a tad of inside rudder (in the direction of the turn), my rate of turn will increase and I’ll be okay. I certainly don’t want anyone to see me go around. They say it’s a sign of a poor pilot.”

“Oh, oh. My addition of rudder has made my bank begin to increase beyond 30 degrees. They say that’s not good. I’ll just add a little bit of opposite aileron to counteract the rudder.”

“Darn, still not getting turned quickly enough. I know. I remember from ground school that if I want to increase the rate of turn, all I have to do is add backpressure. Here goes. DAMN!” The airplane stalls, spins, and probably crashes. And it can happen about that fast.

The pilot in the above scenario has been tempted, trapped, and most likely killed by a combination of hangar talk, misunderstanding of flight dynamics, and poor association and correlation of aviation procedures. He has used some right ideas in the wrong places, ignored the bank-to-stall ratio, and allowed some interesting, but incorrect, precepts to become fact.

Look at the procedure used. He turned too late —added to his problems by adding inside rudder with opposite aileron (a slip), and then added the final piece to the recipe by pulling some more backpressure.

Think about this. The airplane is banked at 30 degrees —airspeed at about 70 knots. A cross-controlled slip is added that further reduces airspeed and increases stall speed. Then cross-controlled, at a slow airspeed, the pilot adds some backpressure. This is one of the best ways on earth to describe the entry to a snap roll, an aerobatic maneuver of immense fun and requiring a lot of skill. It is not designed to be performed by fledgling pilots on final approach!

The solution to this very real and present problem is to plan ahead and start your turn from base to final early enough so you can utilize the ground track procedures you learned earlier. You’ll wind up with an ever-decreasing bank as you reach the final approach course. 

On final, keep aligned with the runway centerline and add the remainder of your flaps as you need them. Maintain a constant airspeed and attitude. Power is reduced as you no longer need it, until, if all goes well, you reduce the power to idle in the landing flare.

If you have the approach pattern down pat, the landing should come rather easily. As I said before, it is just a transition from the normal approach to the landing attitude. This transition usually begins at about 25 to 30 feet above the runway with you slowly increasing the backpressure as you continue to sink. If you have too much airspeed or pull back too rapidly, you might actually climb a little. You don’t want to do that, so increase the backpressure gradually. In a good landing, you almost think of it as trying to hold the aircraft off the ground through increased backpressure. You are transitioning the aircraft from a nose-low approach attitude through level flight to a slightly nose-high attitude at touchdown. If everything is right, you reach the point where you run out of backpressure just an instant be fore the touchdown occurs on the main wheels. Since you are nose high, the nose gear will still be up off the runway at touchdown. As your speed decreases following touchdown, allow the nose gear to lower to contact the runway and thereby provide you with more positive directional control.

The landing is far from complete merely because you are on the ground. Many aircraft accidents occur during the rollout following touchdown. Keep your eyes outside of the cockpit, making sure you are maintaining runway centerline during the slowdown process. You can turn off the carb heat and bring the flaps up after you have cleared the active runway and are positive everything is under control. More than one beautiful approach and landing has been spoiled by the pilot fumbling with something inside the cockpit too soon after touchdown, only to be rudely awakened by the sound of runway lights shattering as the aircraft wandered off the runway. Remember that the control effectiveness steadily decreases as your speed decreases —just the opposite of takeoff. The slower you go, the more control movement it takes to get the job done. Use care but don’t overcontrol in this phase either. Use whatever it takes—no more and no less.

Most of the errors common to landings, outside of a poor traffic pattern, have to do with your sight reference points. Nobody can show you exactly where to look, but you can gain some insight in where not to look:
• Do not look down and to the side while landing. Speed blurs vision, and you will not be able to tell if you are five feet or five inches above the runway by looking down and to the side.
• Don’t look too close in front of the aircraft during the landing flare. Pilots who do so have a tendency to flare high, stall, and drop in.
• Don’t look too far ahead of your aircraft during the landing flare. Due again to depth perception, this causes many pilots to run the aircraft into the ground with little or no flare.
• Once you are in the flare, don’t look inside the cockpit for any reason. You’ve got to see where you are going.

Now that you know where not to look, where do you look? During the short final and flare, look approximately as far ahead of your aircraft as you would if you were in a car traveling at the same rate of speed. If you don’t drive, I guess it’s trial and error.

One other very common problem associated with landing is learning to pull the yoke straight back. I have had students who would begin to flare perfectly, and then at about 10 feet up, turn and try to take it to the tie-down area. The problem lies in flare technique. In most aircraft, the flare requires the coordinated use of the hand, wrist, elbow, and shoulder. If you try to flare using only your hand, wrist, and elbow, the tendency is to twist the elbow up and out, causing the ailerons to be deflected to the right. It also causes a right-turn tendency that can spoil an otherwise decent approach and flare. Conversely, if you pull your elbow in toward your body as you flare, you will experience a left-turning tendency. So watch for these common errors, and if you have trouble in this area, sit in the aircraft and practice pulling the yoke straight back.

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