HOW TO LAND AIRPLANES

© Hal Stoen, June 23, 2000

This tutorial is geared toward the simulator pilot that has not had experience in operating aircraft in the landing environment. The intent is to show what factors affect an aircraft in the landing configuration, and to give pointers and techniques to make the landing phase less demanding and more enjoyable.

This tutorial is not intended to be an all inclusive treatise on aerodynamics and landing operations.

OVERVIEW

We all know the feeling. It doesn't matter what magnificent decisions you have made, or what incredible techniques you have employed during the flight. What counts to your passengers is the landing. Blow that baby, and all of your previous heroics are tossed out the window. And yet, this seemingly simple maneuver can get the best of even the most seasoned veteran pilot.

Let's take a look at what is going on in this phase of aircraft operations.

In the diagram below are shown the four prime factors that affect your aircraft in the landing configuration:

 

THRUST: This is your engine power.

LIFT: The "force" that opposes gravity (weight). It is produced by air flowing in an undisturbed manner over and under the wing. Available lift at slower speeds can be increased by the use of flaps.

DRAG: The opposite, naturally, of thrust. It is the resistance of the body of the aircraft and its surfaces as it moves through the air.

WEIGHT: The greater the weight, the more lift required to maintain flight.

 

CONTROLS AND SURFACES USED DURING LANDING

We're going to assume that the reader has a basic understanding of how an aircraft is operated and controlled in flight. If the reader has not read the "How to fly" tutorial, it is recommended that this would be a good time to take a break and refer to that material before proceeding.

SLATS: Slats are leading edge extensions that increase the overall camber of the wing, producing more lift at slower airspeeds. They extend out from the leading edge of the wing, and may be powered or simply spring loaded so that they extend below certain airspeeds. If you are saying to yourself "Gee, that rather poor drawing up above kind of looks like a Cessna 150 trainer. 150's got slats?' No, although some STOL (Short Takeoff and Land) single engine aircraft do. Most corporate class jets do, as does the majority of the airline fleet. The slats are shown on the "rather poor drawing" just to show their relationship with the other control surfaces.

AILERONS: Ailerons control the rolling motion of the aircraft. Like all control surfaces, they become less effective as the airspeed of the aircraft decreases.

FLAPS: The "kissing cousins" of slats. These extend from the trailing edge of the wings surface. Like the slats, they increase the overall camber of the wing producing more lift at slower airspeeds.

RUDDER: The rudder controls the yaw of the aircraft, the rotation around the vertical axis.

ELEVATOR: The elevator controls the pitch of the aircraft, nose up or nose down.

THOUGHTS ON THE LANDING PHASE

So, why can't you just "chop the power" and glide on down to the runway? Well, you could if the runway was really long. I mean really long. Why? Because a "clean airplane", that is an airplane that is in a cruise configuration, just doesn't want to stop flying. If you insist on putting it back down on the ground while it is "clean" you will have very limited control over where it will touch down. After all, all you can do is glide until the plane loses all of its excess altitude and airspeed.

The whole idea of landing an airplane is to place it where you want it on the runway. In order to do this, you as the pilot must have control over those factors that were shown in the first illustration: thrust, lift and drag. Mother Nature does Her part by furnishing the fourth item, weight (gravity). You want to have control over all facets of the operation. It's all the Oriental Yin and Yang thing. You want to go up- and down. You want to go faster- and slower and so on.

AXIOM

Power controls altitude, pitch controls airspeed. Trust me on this one. Oh sure, for minor changes in one or the other you can go opposite of this axiom, but for all intents and purposes, lock this one in your mind. Power controls altitude. Pitch controls airspeed.

In the following discussion, it will be assumed that you do not have an operating manual for the aircraft that you are flying. If you do have a manual, use the "numbers" that are in it.

AIRSPEED

Look at the bottom of the white arc on the airspeed indicator. That speed is the stall speed with power off and flaps down- not very exact, but a start. Take that airspeed and multiply it by 1.3. For example, if the speed at the bottom of the white arc on your Speedwing is 100 knots, then that number times 1.3 yields an approach speed of 130 knots. Better yet, take you Speedwing up into the practice area and do some power off stalls with the gear and flaps down. Note the speed where the first indication of a stall is. Technically this speed is Vso, the stalling speed of the aircraft in a landing configuration. Take this number and multiply it by 1.3. That will be your approach speed.

Keep in mind that the "multiply by 1.3" is just an approximation. It will give you a starting off point that may be adjusted up or down as necessary. Without a aircraft manual listing definitive airspeeds you will have to do some "Kentucky windage" for your starting off point. If trial and error shows the speed to be high or low, adjust as necessary.

As an aside, doing practice power off stalls in the landing configuration is excellent practice. You should do this with any airplane that you are not familiar with before you practice landings. When doing your stalls, notice how the ailerons, the rudder and the elevator become decreasingly effective as you approach the stall. This is important, and critical information to you as a pilot. This "mushiness" will be your first indication of an impending stall without your ever having to look at the airspeed indicator.

ALTITUDE

How high? Well, figure that you should be about 2,000 feet above the ground when you are about five miles out from the end of the runway. This is not a hard and fast number, just an approximation.

ANGLE OF APPROACH

OK, what angle to use for landing on the runway? If you had a chance to go up with an instructor, he would give this input to you until you had a clear mental picture of where your airplane should be during the approach to a landing. Unfortunately, in a simulator every flight is a solo flight, including your first one.

One way to solve this dilemma is to set up the simulator for practice landings at a runway that has an ILS (Instrument Landing System). Tune in the appropriate frequency and watch the Glide Slope indicator as you practice your approaches. If the "bar" goes up, you are too low, if the "bar" goes down, you are too high. Get a mental picture of how this approach angle looks with relationship to your altitude and distance from the runway.

Another way is to go to an airport that has a runway with VASI (Visual Approach Slope Indicator). There are a variety of styles, but in essence if the far lights are red and the near lights are white, you are on "glide path". What this is telling you is that you are going to land short of the far (red) lights, and beyond the near (white) lights. The aiming point is generally the first third of the runway, but this can vary greatly with the length of the landing surface. If the near lights turn red, you will undershoot and land short. If the far lights turn white, you will overshoot and land long.

Generally speaking, the approach angle will be between 2.7 degrees and 4.0 degrees, with 3 degrees considered as the "average".

GEAR AND FLAPS

The landing gear should be extended by the time you are five miles out from the runway. On an instrument approach, this is usually done at the Final Approach Fix. The gear does not create that much drag quite frankly. Lower it early in the game and have it out of the way. By the same token, lower your "first notch" of flaps just before gear extension. If you are operating a fixed gear aircraft, lower the first notch of flaps when five miles out from the runway. Make certain that you are in the appropriate airspeed range for gear and flap operation. Once again, if you are in doubt about this, please refer to the "How to fly" tutorial.

POWER SETTINGS

For this example, we will use an approach speed of 100 knots, and assume that the airplane has three flap settings. During your approach, adjust the aircraft's pitch as necessary (using elevator input) to maintain your target airspeed of 100 knots.

LET'S FLY AN APPROACH

Let's say that you are more than five miles out from the runway. Reduce power and maintain an altitude of about 2,000 feet above the ground. Allow the airspeed to decrease until you are in the flap operating range (the white arc) on the airspeed indicator. Maintain this speed and altitude until you are about five miles away from the end of the runway. At the five mile point lower your first notch of flaps, then your gear if so equipped. Start your descent towards the runway, using the visual angle that you have pictured in your mind. Remember, this "visual angle" is the one that you have acquired from your practice approaches in the step above, "ANGLE OF APPROAC '. How's the airspeed? Too fast? If you are going too fast, bring the nose up with the elevator to slow down. Too slow? Lower the nose.

How about altitude? Too high? Decrease your power. Too low? Add power.

Continue the approach, adjusting pitch and power as necessary to stay on your "angle of approach", your "glide path". Maintaining your airspeed, and your approach angle, lower your second notch of flaps when about two miles out. Be prepared to add a little power, as you have now increased your drag. In addition, flaps normally will pitch the nose upwards. Be prepared to bring the nose down as the flaps extend downward. This increased drag will lower your airspeed. Adjust your pitch as necessary to maintain the target of 100 knots.

How's the runway looking? What do you think? Are you going to land short? Long? Don't have a clue? Here's a tip that most pilots use in every visual landing. Pick out a spot on the aircraft that you can see as you are looking at your touchdown point on the runway. The spot you pick can be the propeller spinner, a spot on the brow, a spot on the center post, whatever will work for you. (In actual practice, a dead bug on the windshield is an ideal choice.)

Watch this spot in reference to your touchdown point on the runway. If your spot is moving away from the touchdown point, down the runway away from you, then you will land beyond your touchdown point. If your spot is moving towards you from the touchdown point then you will land short. In order for this system to work, you must be maintaining a constant airspeed on the approach.

When you are about 1-1/2 to 2 miles out from the end of the runway, lower your flaps another notch. This increase in drag will require an increase in power to compensate. Also, as before, the nose will pitch up slightly as the flaps extend. Adjust your pitch attitude as necessary to maintain 100 knots.

When the landing is "assured", lower the balance of your flaps. As you cross the runway threshold slowly bring your power all of the way back to the stops. Slowly pull back of the wheel as the aircraft settles toward the runway. In an ideal situation the aircraft will stall just as the main wheels touch the runway. Once the main gear touches down hold the wheel back and allow the nose gear to settle down on its own. Once all of the wheels are down let the elevator control return to the neutral position. Using your rudder pedals steer down the middle of the runway as the airspeed dissipates.

When you are comfortable with the aircraft's situation, and only when you are comfortable, reach over and visually identify the flap lever. When you are positive that you do indeed have the flap lever, and not the gear, raise the flaps to the fully retracted position. This will allow maximum weight transfer to the wheels for better braking. This phase of aircraft operation can be delicate, as your machine is transitioning from being a flying machine to a ground machine

And there you have it! You have just completed the perfect landing. Well, probably not quite. Landing airplanes is like riding a bicycle. No one can really "teach" you how to do it, even if you are in an airplane with an instructor at your side. The instructor can give you all kinds of advice and input, but the "feel" is an acquired thing. It boils down to practice, practice, practice. Even then, things don't always go right. Go out and watch the airliners land, or "enjoy" the experience from onboard. How many are "greasers"? Probably less than 50%.

LANDING IN ADVERSE CONDITIONS

SNOW AND ICE ON THE RUNWAY

Surprisingly, snow on the runway, assuming that it isn't too deep, is not that large of a hindrance. Your braking will be reasonably effective as long as you do not lock them up and start skidding. As far as ice is concerned, only attempt a landing if the runway is "long", and there is no crosswind. You can land on a runway that is covered with solid glare ice if you are gentle with the controls and use minimum braking, allowing the aircraft to slow down on its own.

CROSSWINDS

For crosswind landing techniques, see the tutorial Crosswind landing techniques.

GUSTY WIND CONDITIONS

In these conditions be prepared for turbulence as you get closer to the runway. Take the gust "factor" and add it to your approach speed. If, for example, the wind is at 20 knots with gusts to 30 knots, add the gust factor of 10 knots to your normal approach speed of 100 knots for a final speed of 110 knots.

FINAL THOUGHTS

In this discussion we have been doing "straight in" approaches. In practice, this is not normally done in VFR conditions. In fact, let me say "Don't do it". When you make a straight in approach you are letting yourself in for a cornucopia of problems ranging from a possible mid-air collision to a botched landing.

Most mid-air collisions that occur at airports happen when one or both of the aircraft involved are making a straight in approach. Usually, but not always, they involve a high wing aircraft from below, and a low wing aircraft from above.

Also, it is extremely difficult to judge your distance when you make a straight in approach. Consider this: from an altitude of 2,000 feet above the ground, a runway that is 3,000 feet long and 50 feet wide looks the same as a 6,000 foot x 100 foot runway does from 4,000 feet above the ground.

There is also the "courtesy" to the other aircraft that may be in the traffic pattern at your landing airport. Those aircraft, if present, are flying prescribed patterns around the runway. If you arrive on a straight in you will be disrupting the old apple cart big time.

Lastly, the FAA strongly discourages the use of straight in approaches. While the practice is not illegal nor in violation of any FAR's (Federal Aviation Regulations), it is discussed in depth in the Airman's Information Manual- as close to a FAR as you can get.

So, fly a (traffic) pattern.

In the above example, you may enter the pattern at any of the four legs, including the final leg if you fly over the airport. Normally, the pattern is joined on the crosswind or downwind legs at 850 to 1,000 feet above the airport elevation. Do not fly the pattern too closely to the runway. By doing so you will have to make sharper turns and more rapid altitude changes. Try to fly the pattern so that you will end up with about a three mile final from your base leg. As you become more proficient you may chose to tighten this distance up a bit.

THE BOTTOM LINE

Most landings are botched because of two things: excess airspeed and/or a bad approach. If you are going too fast the odds of your having a decent touchdown are minimal. If your approach is not consistent you will have no basis of reference for the visual clues as you descend towards the runway.

And, lastly, landing an airplane requires strong visual clues to the brain. Most simulators do not present this information very well to the pilot as he nears the surface. For an expanded explanation of this phenomenon go to this link.

So there you go. How to land an airplane in one easy lesson. I hope that this information has been helpful to you. If you see any errors, or if something was not covered in the depth that you would like, please contact me, and I will make the corrections or additions as necessary.

Happy flying!

This narrative, along with aditional content, is available as a CD or an eBook.

For CD information click here. For eBook information click here.

Hal Stoen
© Hal Stoen, June 23, 2000

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