Who Says You Cannot Make your Own Airplane? Series #9: Understand The Concept Of Flight Approach And Landing

Just as it is essential for an automobile mechanic to understand how vehicle is used and every concept surrounding automobile, so is it important for he who wants to make an aircraft from scratch to understand every concept surrounding flight - @teekingtv.

I understand how much you cannot wait to see us start with the practical works regarding building our aircraft. But trust me, you need to understand how an aircraft is piloted before even commencing that. I am breaking every concept being discussed on these series in absolute basics for us to understand pretty quick, pretty well. How about we start this series with a brief recap of our previous series. Thank you.

A brief recap of the previous series:

In order to maintain safety during take-offs and descents, there is what we call a Circuit in the vicinity of an airport. It is a designated path to be flown by aircraft. When flying in a controlled airport vicinity, everything you do around the Circuit is reported to the control tower. A Controlled Zone is the controlled airspace of the defined dimension.
When joining or leaving an uncontrolled airport or airfield, you are more or less on your own. There are several illusions which you may be confronted with under different conditions. You need to understand these illusions in order to know how to avoid being distracted by them.

Full post here.

Just joining us for the first time? I strongly request you check out our previous series: Series 1 | Series 2 | Series 3 | Series 4 | Series 5 | Series 6 | Series 7 | Series 8.

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Today we will deal with Approach and Landing. You will be shown the techniques necessary to safely land your aircraft under different conditions. You will also be made aware of the need to make appropriate decisions on the type of landing you should use.

Before getting to the techniques, here are some general comments. The objective of landing is to get back onto the ground at the lowest possible vertical speeds and the lowest possible horizontal speeds while maintaining adequate control of the aircraft. This will vary according to conditions. Approach and Landing should be considered a continued process.

By this time, you would have had enough flying experience to begin developing your body sense of motion to resist you of landing. But the most important sense is vision. You must learn to estimate distance and depth. As well as being a matter of practice, you must learn how to vie the ground clearly. Close objects become blur at high speeds. As you land, focus farther from the aircraft as you do when driving a car travelling at the same speed. Then, as you slow down, you can focus much closer. If you focus too narrowly or closely, objects will be blurred. The timing of your reactions will either be too quick or too slow.

Another good habit to develop is keeping one hand on the throttle throughout the landing. Then, if you find yourself suddenly in need of power, you can react immediately. It is also a good idea to practice landings from full glides with the engines just idling. This helps you develop the judgement required for first approach landings.

Types Of Landings

Here, we will be discussing about the three types of landings. These are:

• The Normal landings.
• The Crosswinds landings.
• Short, Soft and Unprepared Field landings.

Normal Landings

Normal landings only occur in most ideal conditions. In nearly every landing, there is some degree of crosswind. As well, it is very likely that soft field landing will have a crosswind component towards. A normal landing takes place against the wind. this slows down the horizontal velocity of the aircraft. As you get closer to the ground, you make a slow transition from the normal glide attitude to the landing attitude. This is called the Flare and is started around 15ft to 30ft above the ground.

When started, the Flare should progress continuously until you are on the ground. If your speed is correct, you will start to loose speed as back pressure is applied on the control column. The backward movement of the control column should be such that the aircraft remains just above the ground until landing attitude is obtained.

If you are flying a tail wheel aircraft, the main landing gear on the tail wheels should touch the ground simultaneously. In a nose wheel aircraft, make sure contact with the runway is made with the main landing gear and there is no weight on the nose wheel.

Once you have started the landing process, do not push forward on the control column to upset any backward movement of the controls. If too much pressure had been used, then may be relax slightly or held constant depending upon the degree of error. Also,you may find the need to use more throttle if too much speed has been lost. When you are just 2ft or 3ft above the ground, push more pressure on the elevator control. Because the aircraft is close to stalling speed, this action will not increase or maintain height. It will simply slows the aircraft allowing you to touch the runway smoothly on the main wheels. Remember, it is the attitude of aircraft, not the movement of the control column that determines the completion of the touchdown.

Once on the ground if you are flying a tail wheel aircraft, hold the control column as far back as possible until you come to a complete stop. This prevents the tail from bouncing and slipping. It also improves your directional controls.

in a nose wheel aircraft, let the nose come down gently on its own as your speed decreases and the elevators loss effectiveness. Keep the aircraft straight and avoid excessive speed as this tends to much stress on the nose wheel and causes wheelbarrowing.

Once your instructor has completed the initial stage of your landing instruction, you will be required to plan the approach. As mentioned in the earlier series, pre-landing checks are done on the Downwind Leg of the Circuit. Visualize the Circuit and wear your locator in the traffic floor. Now, estimate where you will reduce your power and when you will turn Final.

Once you are on Base, reduce power and airspeed to begin your descend. Make necessary drift correction to keep you on a round track that is perpendicular to the runway. Fly Base until you are able to turn Final using a medium bank to bring you inline with the runway. This turn must be done on safe attitude and will depend on terrain and any obstruction. It also must be done to give you well enough final approach. It will offer corrections in power and airspeed before touchdown.

The last 500ft of your approach should be straight without any slipping or turning. Control your height by using flaps. Since this will affect the trim of the aircraft, you will have to take appropriate action to control the rate of descend and airspeed. A well executed approach results in a good landing.

To visually maintain your approach, use a prospective method. When viewed from the pilot seat, the runway appears wider at the approach end than the opposite end. If the approach angle is constant, the runway does not change shape. If you steep on your approach angle, the runway appears to get longer and narrower. Conversely, if the angle becomes more shallow, the runway looks like it is getting shorter and wider.

Crosswind Landings

A mentioned before, Normal Landings are rare. You generally have a crosswind component. This is any wind that affect aircraft at an angle towards its longitudinal axis. If a crosswind is not properly managed, it can cause a loss of control. When you land into the wind, you are able to maintain a straight heading with relative ease. But in a crosswind landing, the side of the aircraft is strike by the wind while. And because of the aircraft's tendency to weather cock, it is forced off its heading.

Prior to landing, the crosswind causes the aircraft to drift across the runway instead of holding through on the center line.If you do not take corrective action, the landing gear ends up bearing excess force. The same situation occurs if the part of the aircraft is held through to the center line with drift compensated forward by crapping and the wheels touching the ground not aligned with the runway. Crosswind landings tend to be more difficult than Crosswind take-offs. This is because during landing, you loose speed which in turn reduces the effectiveness of flight controls.

Methods For Landing In Crosswind

There two basic methods for landing in a Crosswind. These are:

• Side-slip or Wind-down method
• Crabbing the aircraft to compensate for drift.

Side-slip Method

This method is the most popular and the easiest for beginning pilots. When using this method, avoid to beginning to slip too soon on the final approach unless of course, there is another reason to slip. As you approach the runway and the drift becomes apparent, side-slipping into the wind to counteract the drift. Use the rudder to keep the longitudinal axis of the aircraft align with the central line of the runway. Once you have touched down, be sure to keep the aircraft in a straight line to avoid ground loop. The aileron control should be held towards the upward wing after touchdown to prevent it from rising out of control. When using the Side-slip method, make sure the upwind main wheel makes contact with the runway first.

Crabbing

This is the second method of landing in Crosswind and it involves maintaining a heading or crabbing the aircraft into the wind so that its flight path is aligned with the runway. This means the longitudinal axis of the aircraft is not aligned with the runway just prior to touchdown. If alignment is achieved, there is a possibility of causing damage to the landing gear or difficulty in controlling the aircraft. Therefore, it is critical that at the precise moment the aircraft touches the runway, it is made in line by the use of the rudder.If contact is made too soon, the aircraft will land with crab. if contact becomes too late, you will land with drift.

Now, onto the third type of landing, The Short, Soft and Unprepared Field landings

Short, Soft and Unprepared Field landings

The third type of landing we will be discussing here is used when you encounter Short, Soft and Unprepared Field Landings. During the approach, you want to reduce the airspeed as low as possible while still maintaining the maximum of control. Usually, you approach with the Flaps extended. Check the aircraft manual for the recommended airspeed. Factor in the Gust Factors to the approach speed when appropriate. The need for a lower approach speed lessens when winds are strong.

In Gusting condition, you should have an equal amount to have the Gust Factor in your approach speed. For example, if the wind gust from 20 to 40, the gust Factor is 20. That means you should add 10 to your normal approach speed to allow for Gust. Your altitude will vary according to the height of obstructions in your approach path. Using power for this type of approach gives you more accurate control of descent. It is important that the flare be judged accurately to avoid stalling or flying into the ground. Leave the power on until the flare is completed. Touchdown should be at the minimum controllable airspeed and the pitch should approximately that of the power of stall.

Nose wheel aircraft should be held in this position as long as the elevators remain effective. Tail wheel aircraft should be held in three points attitude during breaking. Flaps should be retracted as per the recommendations of the aircraft manufacturer.

In soft or unprepared fields, note the followings:

• In nose wheel aircraft, hold the nose wheel clear of the surface as long as possible and use the breaks sparingly to prevent excessive loads on the nose gear.
• In tail wheel aircraft, the tail wheel should touch down just before the main wheels. Use the elevators to hold down towards the landing roll.
• The use of flaps will depend on conditions. Keep in mind that the Flaps on low wing aircraft may be damaged by mud, rocks and slash thrown up by the wheels.
• Usually, breaking is not required on soft surfaces and in fact, may cause other problems.
• When landing over obstacles, the techniques are generally the same as for a Soft Field landing. What will vary is the steepness of the approach.
• To save flight time time, you may decide to practice Touch and Go landings. In this procedure, the take-off is executed while the aircraft is still on its landing roll. You will have to do the essential pre-take-off cockpit checks while the aircraft is still moving on the runway. Before these checks are done, the aircraft must be under complete control when landed.

Essential Pre-take-off Actions

Now let us take a look at the essential pre-take-off actions. These actions are listed below:

• Put the flaps upward, set them for take-off.
• Set the trim for take-off.
• Make sure the Crab Heat is off.
• And use full power for take-off
• Also, if you are operating out of a controlled airport, you will need clearance for touching gear landing.

There are several factors that affect the length of the landing run. Crosswind will lengthen it due to the diminished wind and in case of 70 to 90 degrees crosswind, you may have to land as if no wind condition exist. When encountering a light or shifting winds, plan the landing run as you would under a no wind condition. Occasionally, you may have no choice but to land on a tail wind. When landing under these conditions, retract the Flaps and neutralise all flight controls as soon as possible after touchdown.

Some runways have a slight gradient which can lengthen your landing run. In some cases, it might be advantageous to land uphill with a slight tail wind rather than deal with the effect of downhill gradient. Bear in mind that the heavier your aircraft, the more runway you will need to land. This becomes especially important if you are landing on a Short field with obstacles on the approach, a slippery surface or under light wind. Grass surfaces providing resistance to the landing gear can be deceiving. Wet grass can reduce your breaking capability by 30, meaning the landing roll will be longer than a wet hill surface.

We have talked about the effect of Hydroplaning and Wheelbarrowing while discussing about the concept of take-off. However, these do not only affect the take-off procedures but also need to be understood when landing is concerned.

When landing on a wet surface, be aware of the danger of Hydroplaning. This occurs when the tires of the landing gear are separated from the runway by a thin tame of water. Hydroplaning can cause up to 700% increase in the stopping distance. If you suspect Hydroplaning, release the breaks immediately and reapply with a slight pressure. Increase the pressure as the aircraft slows.

Wheelbarrowing occurs on a nose wheel aircraft when the nose wheel is allowed to touch the runway first. Ina Crosswind, the aircraft may yaw about the nose causing a loss of control. Other symptoms of Wheelbarrowing include Wheel skipping and an extreme reduction in breaking effectiveness. To correct Wheelbarrowing, do the followings:

• Close the throttle
• Relax the forward elevator pressure to the neutral position. This will lighten the load on the nose gear.
• Return stirring and breaking to normal.
• If control is regained and there is enough runway left, abort the landing and go around again.

Ground Loop is associated with tail wheel aircraft and it is a violent uncontrollable swing which occurs on landing or take-off. Okay then, I know it that as you hear of loop and swing, your mind go straight to a programming language and JAVA to be precise, but trust me, I understand that feeling. We ain't talking no programming language here buddy!

Ground Loop is caused by half-a-dozen different situations. It may result from touching down while crabbing into the wind or touching down while the aircraft is drifting sideways. It can also be caused by a crosswind acting on a visualised rudder weathercocking the aircraft into the winds. Allowing the upwind wing to rise with weathercocking can also produce the condition. Failure to control wheel landing properly or incorrect recovery actions for drift after a bounce are other two causes.

Preventing Ground Loop

To prevent Ground Loop, take the following actions immediately:

• Keep the control column fully back.
• Apply opposite rudder.
• That is not enough, open the throttle to make the rudder more effective.

And remember, never attempt to realign the aircraft on the runway until you have a positive control. If you are starting to get into trouble while landing, go round again if there is enough runway to do so. Remember, Air Density will affect the length of your landing roll. The landing roll will be longer in warmer air and at higher altitudes. Combining both makes the landing roll even longer.

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This section deals with some irregularities you may run into while landing.

Irregularities that may Occur In Landings

If you should touch down too soon, there is a tendency for the aircraft to bounce into the air again. The action you take depends upon your airspeed. If it is high and the bounce is small, release some of the backward pressure on the control column and allow the aircraft to descend. When you are at the correct height, fly out into landing attitude. If the airspeed is low and the bounce is high, apply power to resist in the fly out to prevent stalling. If the fly out is premature, the aircraft may start to climb. Check the backward pressure on the control column and descend to the height. If the airspeed is too low, apply more power. Close the throttle before trying to regain the landing attitude and then fly out into the landing attitude again. Also, keep in mind that recovering from bounce will mean you will have to produce any necessary drift correction.

Overshoot

The decision to overshoot a runway because of a poor approach of landing is solely with the pilot. Once that decision is made, apply full power and accelerate to a safe climb speed and level flight. Reduce Flaps extension as required and raise the nose. Stay straight as you open the throttle and roughly trim off the pressure on the control column. Start climbing as soon as you have control of the aircraft. Raise the flaps, adjust climbing speed and retrim.

If a bad approach of landing is because of the overshoot and the remaining runway is clear of other aircraft, you may climb straight ahead. If visibility is a problem, move to the right of the center line fly parallel to the runway and while climbing, keep a look out for other traffic. When overshooting, if the Carb Heat is on during the approach to landing, it should be turned off as soon as possible after power is applied.

Wake Turbulence

We discussed about the effect of Wake Turbulence on take-off in the previous series. It can also affect you if you are landing behind a large aircraft. When flying behind a large aircraft, remain above its flight path. If you are landing behind a large aircraft that is just taking off, touchdown prior to the point where the large aircraft rotated. If a large aircraft has just landed, plan to land behind the point where it touchdown.

Remember, if you believe it is safer to use and alternate runway, ask the control tower for advice and clearance. at controlled airport, you must receive clearance to land. Normally, it is given without being asked for. If you do not receive clearance, do not land. Unless there is an emergency, overshoot. After landing, quickly vacate the runway. Clearance for taxiing after vacating the runway is from the control tower. You will likely be cleared to ground control. If this service is not available, you will be told to taxi somewhere between the landing roll and the point where you stop to do the post-landing cockpit check.

Conclusion

I am believing that by this time you have now understood that there is more to piloting an aircraft than just getting into the cockpit, start the engines and take-off and then descending. There are much more procedures that must be followed for a safe flight. The type of landing you choose as a pilot depends on the conditions present at the time. Lot of factors cause the conditions. And there are irregularities that may appear during the flight. Before we can start building our aircraft, it is essential that we understand how the aircraft is flown. After all we are going to be the manufacturer of one, then we need to understand every concept surrounding it. We need to take a break here. Soon we will be meeting again on fresh concepts.

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References

• Landing
• Approach and landing
• Difficult Descent: 4 Tricky Kinds of Airplane Landings
• Ground loop
• Crosswind landing

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Previous Lessons In The Series

• Series #8: Understanding The Airport Circuit, Control Zone & Dealing With Flight Conditions Illusions
• Series #7: Understanding The Aerodynamics; Spin, Spiral, Slip And The Concept Of Take-Off
• Series #6: Understanding The Concept Of Slow Flight and Stall
• Series #5: Understanding The Flight Maneuvers; Climbing, Descending & Turns
• Series #4: You've Got Attitudes, Aircraft Got Some Too
• Series #3: Understanding How Jet Engines Work And Effect Of Atmosphere In Flight
• Series #2: Understanding The Thrust Mechanism And How The Engine Works
• Series #1: Understanding The Mechanism Behind Airplanes And The Misconceptions

Till we meet again on my next post, well I am not changing my name. I am @teekingtv and I write STEM! THANK YOU FOR READING. GOD BLESS.

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