March 1, 1993
RICHARD L. COLLINS
About half of the total accidents that occur in general aviation come during landings. Probably 90 percent of the severe ego bruises that occur in general aviation come during landings. Witness the following story, told by a person who swears it is true. The captain was flying the 727, landing in a gusty crosswind. He thought he had everything just right when, zap, the wind chose that moment to rest its case. The Boeing thumped onto the runway with enough force to open overhead bins and make passengers gasp. As was company policy, the captain had to stand in the cockpit door, smile at the passengers, and thank them for riding Amalgamated Airways as they departed. He was blushing the whole time, though nobody mentioned the landing until the last person to disembark came along. She was the world's grandmother, 4 foot 7, with a pearl- handle cane and little round glasses. She shuffled up to the captain, looked up at him, and said, "Tell me, sonny boy, did we land or were we shot down?"
Anybody who hasn't also experienced that captain's mortification hasn't landed much. I have been flying the same airplane for 14 years and 6,100 hours and still have it in my power to make awful landings in it. Experience is not a key to smooth arrivals. In talking with other pilots about this, confessions abound even about airplanes that are considered "easy" to land. The challenge is always there, which is one of the wonderful things about flying. I remember standing and watching the video of Neil Armstrong's manual landing on the moon and thinking, "Gee, why can't I do that well in a mere airplane?"
At a recent function, I was visiting with a student pilot. He told me that landings were a big hang-up. He just wasn't getting it and asked my advice. I told him that his flight instructor really couldn't teach him how to land. The instructor's real role is to protect the airplane and the student while the student teaches himself how to land. "It'll come to you," was my final word to the student. He soloed the next morning. It apparently came to him. What about the rest of us?
One thing that seems to help me is to examine the things that lead to a string of excellent landings. There are three primary activities that make my general landings better. Seaplane flying, helicopter flying, and tailwheel airplane flying all help — a lot. Why? Because all three of these activities are totally demanding of the judgment of height and the management of energy.
You have to literally fly a seaplane onto the water. There is no shock absorption available, and as anyone who has ever done a belly flop will attest, the water is quite unyielding. In a glassy-water landing, where the visual judgment of height is difficult, the descent management has to be so good that you perceive when the airplane enters the ground or water cushion, which extends upward to a distance equal to about half the wingspan of the airplane. There is a perceptible decrease in descent in the ground cushion; there is also a slight nose-down tendency. These subtle changes are not noticed by most pilots when flying a tricycle-gear landplane, and this illustrates one reason we make bad landings in tricycles. The concentration on detail has to be there in a seaplane; it does not in a Cessna 210, for example. In the mere airplane, we can drop it in a foot or two and get away with it.
In helicopter flying, too, the beneficial effect relates mostly to the judgment of height. When you are hovering and moving around down low in a helicopter, you absolutely have to have a keen awareness of height. The same goes for an autorotation, which might be compared to a power-off approach in a Skyhawk, for example, at a speed 2 knots above the stall. Missing the height by a foot is a big miss; missing by 3 feet can be a big mess.
When a helicopter instructor tells you to lift off and hover at 3 feet, he means 36 inches. Do that for a few hours, and you will know where the ground is located on your next few landings in a fixed-wing airplane.
Finally, the tailwheel airplane helps because it talks to you. When I used to instruct in Cubs, I loved the landings more than anything else because the Cub was such a good teacher. In a tricycle, a student can make a landing that you don't like — level on all three wheels, for example — but it can also be a landing that feels good to the student. Cubs seldom allow that. They bounce, or "crow hop" as we used to call it.
Perhaps a key to landing woes is the tricycle landing gear. When Cessna first came out with the 172, then a tricycle version of the 170 except for a different vertical tail, the landing gear was dubbed the "Land-O-Matic." Presumably, that was as in "automatic." Some of the promotions suggested that you could now take a drive in the sky. The trouble is, making consistent good landings and avoiding accidents in tricycles is just as demanding as in tailwheel airplanes, and the technique is similar if not the same. It all has to do with attention to detail, judgment of height, and the management of energy.
The landing begins when we flare. How high do we flare? You can ask a number of pilots and generally get a number of different answers. When I suggested to one that we flare at about 15 feet, he thought that far too high. Where did I get the number? That is the number off the radio altimeter (that gives main landing gear height above the runway) the flight engineer reads out to the pilot flying a Concorde as a signal that the approach has ended, and the landing has begun. We don't fly Concordes, but 15 feet for the flare works for us, too. In our airplanes, it is the height at which we begin to fly into the ground cushion — half the wingspan.
In addition to the decrease in rate of descent and the slight nose-down pitching moment that occur in the ground cushion, something else happens. The airplane decelerates about half as rapidly. That effect probably begins as the ground cushion is entered and increases as the airplane goes lower. You start to see it at about 15 feet in an average light airplane.
The 15-foot flare came from one more source. In studying video of several landings by one pilot, it looked like the flare started at about that height in most of the landings. The touchdowns that followed looked okay.
Before we examine the rest of the elements of a landing, one thing needs to be added about the judgment of height. As we grow older and start to wear glasses, our peripheral vision probably suffers. At least there is no correction on a lot of the area of peripheral vision. An abrupt change occurs where the correction ends. The big picture of a landing thus becomes somewhat smaller, and perhaps older pilots have to work a bit harder at landing than younger ones. Personally, I find this to be a little bit true in the daytime and a lot more true at night. It becomes even more complex when bi- or trifocals are first obtained. It may be wise to fly some landings with an instructor if you get new glasses.
One prerequisite for a good landing has to be a proper approach. Forget the part about having a stabilized approach from some far-out point on final to the runway. As far as the landing goes, the important thing is for the airplane to approach the landing point at the proper speed, trimmed for that speed, and at a pitch attitude that will maintain that speed. Most of us probably come over the end of the runway at 40 to 50 feet. If the previous requirements are not met at that point, then the landing probably will be lousy.
Pitch attitude is often neglected, mainly because pilots become slaves to airspeed indicators and push or pull on the wheel as required to move the airspeed needle. The airspeed may be correct at the point when we begin landing, but if the attitude is not right, the airspeed soon will change. If the airspeed is varying, as on a gusty day, having the pitch attitude correct means that the airspeed will always seek to return to the proper value as the effect of the gust passes. A strong wind shear is another matter and must be handled with both a power adjustment and a pitch change.
While there is an apparent difference in the landing that follows a power-on approach as compared with a power-off approach, the difference is not great. Each type of landing really begins at the same time. The difference is that the change in pitch to fly from the approach attitude to the landing attitude is greater on the power-off approach.
The best landings begin at 15 feet, and the rate of descent from that point on to the runway is constantly decreasing as is the airspeed — until the airplane is at 1 foot. When 1 foot high, the airplane is probably about 3 to 5 knots above landing speed. These knots are then gingerly swapped for that last foot. In most airplanes, the touch has to be really gentle for it to feel like a perfect landing.
We seldom fly in such a perfect world. Wind and turbulence take their toll. We have to accept this and still make the airspeed and altitude come out even at the runway surface.
In tricycle-gear airplanes, the key to avoiding the landing accident is to know the acceptable landing attitudes of the airplane and not let it contact the runway in any other attitude — which means never land on the nosewheel first or on all three wheels at the same time.
There is nothing wrong with full-stall landings in trikes — purists insist on them — but the heavier the airplane gets, the less desirable they become. The simple fact is that if you are making a full-stall landing in a trike, you are landing with no margin. If the airplane balloons upward a couple of feet just as the stall is reached, or if height is misjudged a bit, only a blast of power can prevent a plop onto the runway. The moment a power increase becomes an essential part of a landing, the maneuver is seriously compromised. A variable is entered on top of all the other variables present in a landing. If you know the minimum acceptable nose-up landing attitude and shoot for a touchdown with the nose just a little higher than that, in most airplanes you have a lot of margin to use in dealing with variables. I like, on landing, to think in terms of being allowed to let the airplane touch at any time after the acceptable landing attitude is reached.
At forward center of gravity, some airplanes require full aft elevator on landing just to touch with the nosewheel barely clear of the runway. That is the only way to land these airplanes. The Beech Baron is just one example.
The configuration of the airplane affects landings. In a low-wing airplane, especially one with a short landing gear, as a Mooney, the wing is lower in the ground cushion at touchdown than is the case with a high- wing airplane. The airplane decelerates more slowly during the last part of the landing, and any excess speed results in floating. The only way to deal with this is to avoid that excess speed, begin the flare at the proper height to lose some of the speed before the airplane is quite low in the ground cushion, and carefully manage the swap of airspeed for altitude.
The use of flaps is an important part of landing management. There is no light airplane for which it can be said that full flaps should always be used for landing. There are crosswind conditions where the use of full flaps can compromise the safety of a landing. Also, the flaps may not work, which is why the flapless landing is covered on many check rides.
Using less than full flaps when landing in a strong crosswind or with a strong gusty wind down the runway means approach and touchdown speeds will be higher, so controllability will benefit. The approach attitude will be closer to an acceptable landing attitude. Deceleration will be less rapid, so there will be more margin between reaching an acceptable landing attitude and a full-stall touchdown — just have plenty of extra runway. Every airplane is different, so flaps management is something that has to be practiced and learned for each type — with an instructor experienced in that type.
Some pilots like to run nose-up electric trim during a landing to lighten the elevator loads. That seems to me to be a bad thing to do because it takes all the feel out of a landing. As in any phase of flight where we are flying below the trim speed, the force we have to exert on the elevator control to land tells us how things are going and where we are on the way to running out of elevator. Trimming effectively removes the stability. Piper once put a button on the wheel that you could hold down, and it would automatically trim away all elevator loads — not a good or enduring system. If pilots are so weak that they can't land without trimming, an exercise program might be a good idea. Also, if the trim ran to full nose up and a go-around had to be executed right at the last, it might be a difficult time.
Once the airplane touches the ground, what next? This depends on the type. Some pilots like to hold the elevator control aft and take advantage of aerodynamic braking from drag. That is fine, but if it is gusty, you might get to make another landing. Also, if doing this compromises forward visibility, it would be just that — a compromise. One thing not to do in a retractable is put the flaps up right after landing. Many retractables have wound up on their bellies because of this — perhaps as many or more than have been landed gear up — and until you can look at and verify that it is the flap switch you have selected for an upward motion, best leave it alone. If there is a strong wind, the airplane should have been landed with less than full flaps, so there should be no immediate need to retract them because of the wind.
It has been said that a landing depends on a good approach. It has also been said that the landing hasn't been completed until the airplane is parked. The part that affects our ego most, though, and that impresses passengers the most, is that sweet and challenging time from 15 feet to the ground. If the airplane was at 1.3 times the stalling speed at the beginning of the landing, then getting rid of at least two tenths of that speed and reaching 1.1 VSO when 1 inch high should result in one good touchdown. One other thing — next time you think about "shooting" some landings, try flying them instead.
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