by Harold Green
The previous “Flight Training” article in Midwest Flyer Magazine, ended with the turn onto final approach and the establishment of a stabilized approach at a predetermined airspeed at least 250 feet above the runway. Now, we will complete the landing. Note once again that what is presented here is not to be considered as the be-all and end-all of landings. It is merely one instructor’s approach and is offered only to add perspective. We will only discuss light aircraft operations. While the fundamental procedures are basically the same, heavier and higher wing loading aircraft require additional considerations than those we are discussing here.
Landings are the principal challenge of most students, and crosswind landings are the greatest difficulty for everyone. Landings combine principal basic elements of flight with the pilot’s skill, obvious to all who are watching – and who doesn’t watch other’s landings? However, the most serious impediment to learning how to land an airplane is the psychological reaction of the student. Usually students are so tense they interfere with their own learning. Once this is out of the way, true learning begins. For our purposes, we will divide the landing phase into the following steps: final approach, leveling, rotation and touchdown.
The Pilots Operating Handbook (POH) specifies the speed on final approach, and the power and flaps by the instructor.
There are two lines of thought with respect to power and flaps for landing. One school of thought likes full flaps and power, while the other school prefers minimum flaps and no power. My preference is for Vg as a speed, with minimum flaps and no power during training because this teaches aircraft attitude control and ensures that students do not become dependent on power to correct their approach. It also develops a finer sense of path projection. Finally, and perhaps least important, in the event of an engine failure, the procedure and sight picture are the same as practiced every day.
The final approach is the first actual opportunity to judge where the touchdown point on the runway is. Watching the desired touchdown point in the windshield does that. If that point moves up in the windshield, we are aimed below it and, conversely, if it moves down, we are aimed above it. NOTE: The projected touchdown point is that point where we would touchdown if we did not have to level and rotate to slow down when reaching the runway.
Of course, the actual touchdown point will be beyond the projected point because we need to bleed off airspeed so the airplane will stop flying. It’s worth pointing out that the projected point will hold still as long as we hold the aircraft pitch, and hence airspeed stable. If we are high, we can slip, S-turn or use flaps. If low, a little power helps.
After we gain proficiency, we can vary speed a bit as well. Of course, this means we have to keep an eye on the touchdown point. However we do it, power should be kept as constant as possible. Laterally, the airplane should be aimed at the centerline of the runway and kept lined up with it.
During this time, one should not focus on the projected touchdown point to the exclusion of scanning the runway. Throughout the entire landing process, a constant scan of the runway should be employed because focusing on one point produces “target fixation” and one is likely to overreact or possibly fly into the runway.
Typical Errors On Final
1. Lack of runway awareness, either by ignoring the runway or fixating on a point.
2. Inadequate speed control resulting in a changing requirement from landing to landing or arriving at the leveling point with too much speed.
3. Failure to maintain track with the runway center.
Leveling begins when it becomes necessary to bring the airplane to level pitch, or approximately so, to bleed off speed, or, if you like, to get rid of excess kinetic energy.
This is a good time to remove any remaining power, if it hasn’t all been removed on final. The height at which this happens depends on aircraft speed, pilot preference, and experience. If the pilot has had target fixation, the reaction is a delayed recognition of the need to level, resulting in a rapid rotation with the airplane climbing rapidly and with insufficient energy input to sustain the climb, resulting in either a stall or overreaction, again causing the plane to land on the nose wheel. This can then result in “porpoising,” which can go on and on and, in extreme cases, take the nose-wheel off the airplane. If the airplane pitch is changed too rapidly, the plane will tend to climb, which is not what we want. It may be necessary to add power and go around at this point.
Leveling the airplane allows the plane to slow down and settle at the same time since the power will be insufficient to maintain altitude. Naturally if you have been carrying power, this is the time to reduce power to idle. This can be done beginning at a wide range of heights. The higher we begin, the slower the pitch change needed to achieve level attitude at the appropriate height above the runway. Also, the higher the process begins, the more time the airplane is exposed to gust disturbances, crosswinds, etc., while slowing down. Further, gust and crosswind effects tend to be reduced by ground effect, so the lower you are, the less the impact. So beginning to level the aircraft at a lower altitude makes it somewhat less subject to these disturbances.
The actual height to begin this process cannot be defined and, even if it could, how would one measure it? This judgment must be developed through practice. It also becomes part of the process in becoming acquainted with any new airplane.
Practice tells us what it looks like over the cowling. During this process, scanning the full runway length, with the most time spent looking far down the runway, is the best technique. At this point one can begin to develop a sense of perspective by being aware, via peripheral vision, of the lines of perspective and form a type of instrument to judge height above the runway. To hold the attitude, continual pressure needs to be applied to the elevator control. However, this should not even be a conscious thought.
Just focus on holding the attitude without regard to control input. If a gust of wind is encountered, the plane will experience a sudden increase in airspeed and hence lift, or if there has been an excess of exuberance in leveling the airplane, it will climb momentarily. In this case just relax, keep the nose level and then re-enter the rotation phase. If the resulting gain in elevation is too great to recover, it is time to add power and go around, remembering to keep the pitch attitude low enough to prevent a stall. Eventually, despite your efforts to prevent it from doing so, the airplane will settle onto the runway. If that is done properly, the airplane will gently settle with a squeak.
Typical Errors While Leveling
1. Failure to maintain awareness of the runway center, allowing the airplane to migrate to one side of the runway.
2. Fixating on a point close to the plane and losing track of the airplane height above runway.
3. Overreacting and changing pitch too rapidly, causing the airplane to “balloon” back into the air.
4. Failure to go around when required.
The actual touchdown occurs because the airplane is unable to sustain level flight at the power available. As the airplane settles, additional effort should be maintained to keep the airplane from landing. We know it is going to land…we just need to be patient. The pitch attitude should be maintained as the wheels touch the surface. (In a tail dragger, this would mean a stall just as the plane touches. Tricycle gear folks can get away with being not quite in the stall when at this point.) Once on the ground, do NOT simply release the elevator pressure. This could cause the airplane to become airborne again, since the angle of attack will decrease below stall and off you go again. In the case of a strong crosswind, the elevator control should be placed to hold the airplane on the ground. (See the discussion of crosswind techniques at the end of this article.)
Here is the principal difference between nose wheel and tail draggers. Often the nose wheel pilot can get away with not keeping the nose elevated, but the tail wheel guy can’t. A tail wheel aircraft will land with a much higher angle of attack, and releasing the backpressure will cause it to try to fly again. The pilot’s attention should be centered on the end of the runway to aid in maintaining a straight-line roll out. Remember, the landing is not complete until the airplane is safely parked.
Typical Errors On Touchdown
1. Failure to maintain runway awareness, allowing the airplane to migrate to one side of the runway.
2. Premature release of backpressure causing the plane to fly again…briefly.
3. Improper use of ailerons in a crosswind to hold the plane on the ground.
4. Failure to fly the airplane until it is safely parked.
Crosswind landings are always a challenge for the student. There are two basic approaches to accomplishing a crosswind landing: slip and crab/kick. In the slip technique, the plane is banked into the wind and the rudder is used to keep the nose pointing down the runway. As a result, the ailerons become the “slider” and can be used to keep the airplane lined up with the centerline, and the rudder becomes the “pointer” keeping the nose pointed down the runway to avoid touching down with any side motion.
Flaps should be minimized when using the slip technique because they will limit the rudder authority. With the crab/kick technique, the airplane is crabbed into the wind to keep it tracking down the centerline and, just as the plane is about to touch down, the rudder is used to point the airplane down the centerline.
Excessive flaps here can prevent the airplane from yawing sufficiently to point down the runway resulting in a side load on the landing gear. At the same time, upwind aileron is brought in to keep the wind from getting under the upwind wing. Given the gusty or turbulent wind conditions that typically prevail in strong crosswinds, it is not unwise with either technique to carry a little extra power and/or speed on final to help counteract the wind effects. Power will also help maintain rudder effectiveness as the airplane is slowed for landing. Also, once on the runway, it does not matter which technique you used to get there, but the ailerons should be held full into the wind and perhaps elevator control should be used to keep the plane glued to the runway. Recognize that in really strong crosswinds, it may be necessary to maintain some power well into the landing roll.
While crosswind landings present a challenge to learn, there are few things in flying that provide more satisfaction than a well-executed landing under difficult conditions. The most common problem is a reluctance to use the necessary amount of control to maintain the desired sight picture.
Frequently Asked Questions:
Q. When do I go around?
A. Whenever you feel any doubt about the outcome. Remember the name of the pilot who goes around is unlikely to be named on the National Transportation Safety Board (NTSB) report.
Q. How much control movement should I use?
A. Whatever it takes to maintain the desired sight picture.
Q. How do I learn all this?
Practice, my friend, practice!
EDITOR’S NOTE: Harold Green is a Certified Instrument Flight Instructor at Morey Airplane Company in Middleton, Wisconsin (C29). Email questions or comments to: email@example.com or call 608-836-1711 (www.MoreyAirport.com).