Home

Aviation News

Flight Training

Aviation History

Theory Of Flight

Airframes

Powerplants

Civilian Aircraft

Military Aircraft

Aviation Wallpapers

Aviation Links

Contact


 

 

 

Contents

Landings (opinion)
Increase the prediction rate, and try not to be chasing only reaction.
Santos Ramos

Landing Elements
The future structural integrity of an aircraft depends upon how it is landed. The gear box, the crucial connection between the gear and the fuselage is perhaps the strongest single part of an aircraft. Yet, under repeated severe impact the box can weaken and fail. Under normal landing impact the gear box can last the life of the aircraft without incurring weakness or failure.

Slow landings will assure the longevity of the landing gear and therefore of the aircraft. Why slow instead of soft? The very best pilots will touch down while holding a high angle of attack and as slow as he can get the plane. The resulting slow touchdown may be physically firm but 'soft' on the structure of the aircraft. The mental requirement for such a landing is just keep trying to hold the aircraft in the air as long as possible.  Let the aircraft choose when it will land.

The stabilized approach has a constant airspeed. The visual picture of the approach slope is maintained initially with flap application, next by power changes, and finally by airspeed changes. The ideal would be maximum flaps, constant power, and constant airspeed. The roundout is planned to give a level ground effect flight path with the wheels about hip high over the runway. The airspeed will decrease but is NOT a part of the pilots visual scan. The pilot has his eyes initially on the far end of the runway. The nose is held up to keep the far end of the runway covered without raising the aircraft altitude.  You will not see the runway on making ground contact with the main landing gear.  You will continue to hold the nose wheel off the runway as long as possible.  You can increase 'possible' by removing flaps..

A very weak elevator feeling can be felt as the aircraft begins to sink to the runway. In anticipation of this sink the pilot must gradually raise the nose without causing the aircraft to rise. This is the flare caused by a gradually increasing speed in the back and up movement of yoke to hold the nose covering the far end of the runway. The yoke movement can be accompanied by a gradual reduction of any power remaining. Ideally, when the yoke is full back and up and the power is off the aircraft will decide to land.

The ideal landing does not occur with a full stall ground contact. The ideal occurs before the stall as audibly indicated by the stall warner. The stall warner is usually activated five-knots before the actual stall occurs. The ideal ground contact has no side loads imposed on the landing gear. The vast majority of landings occur in crosswind conditions. The more gentle the crosswind and the more slight the angle the more difficult it is to detect and make compensation for. Crosswind corrections are obtained by having the nose aligned on the centerline and a wing held down just enough to counter the drift caused by the crosswind. The most common fault of the pilot is failing to make changes as they are required prior to touchdown. Wind velocities and angles are not constant. Hence, constant adjustments of both rudder and aileron are required of the pilot. There is no standard of rudder or aileron. You DO whatever it takes to keep the nose aligned and the drift countered. Aligned is NOT of necessity on the center line.

Law of Primacy
There is probably more poor instruction done during the practice of touch and go landings than any other phase of learning to fly. Remember the student doing solo is self-instructing. Doing touch and goes is equivalent to learning to drive by going around the same block over and over. Some of the procedures inherent in the touch-and-go are contra-indicated in normal landing procedures.

Good procedure requires a pilot to put in the power before retracting the flaps as in a go-around, but the touch-and-go trains otherwise. During the rollout the student brings up the flaps, puts in the power and goes. All of the touch-and-go procedure requires some reference inside the cockpit to controls and instruments while rolling at high speeds. This again contradicts what will later on be considered good procedure. Good procedure in any complex aircraft says not to retract flaps while on a runway since the gear lever may become involved. The law of primacy is constantly being abused when we teach touch-and go's.

I do the vast majority of my initial landing instruction by incorporating less than 25 mile planning to adjacent airports. This teaches the pilotage, radio procedures, traffic avoidance, ATC requirements, and pattern entries that cannot be part of in the pattern flying. My first landing lesson consists only of go-arounds at increasingly lower altitudes speeds in both left and right patterns. I show that the go-around can be initiated at any point in the pattern, as well.

Landing
Every landing can be a precision landing within limits. Unlike a glider, where an airplane touches down is a function of airspeed, ground effect, and pilot control. A spot landing can be 'faked' by the use of power or rather the abrupt reduction of power. I recommend using the runway threshold as your aim point for flare and then use the yoke and power for the lowest possible touchdown speed. For practice, use a flare-point up to a thousand feet down the runway to allow for any misjudgment you might make in your approach to the 'displaced' threshold.

Pre-decide under what circumstances you will execute a go-around. You do not need to wait for the runway threshold to make a go-around. A go-around can be made on downwind if something occurs on the runway to prevent a landing. Turbulence or extreme winds can affect your downwind, base or final to preclude a landing. Go-around. Being high, low, with a fast or slow ground speed can precipitate a go-around situation. The major factor of any go-around is to do it without hesitation or doubt. Practice of go-arounds should not consist of over the runway situations.

Begin your airspeed control and configuration adjustments abeam the numbers. Use your downwind airspeed and distance from the runway to set the initial parameters of your pattern. Adjust trim and flaps with a constant power setting for wind conditions. On final, put in full flaps to keep the flare point at or in front of the threshold. Corrections for being low consist ONLY of full power while holding approach speed. Corrections for being high consist of maximum flaps for wind, power reductions in increments as required to adjust glide slope at constant airspeed. Trim. Slow down to Vref of 1.2 Vso. Being high or low is visually determined by any closing or flattening of the space between the flare point and the selected touchdown. Make a final check of the windsock to determine if the landing can be made with existing flaps. If not, go-around.

Throughout the approach all speeds and configurations are at constant power and trimmed for hands-off control. The POH has a recommended approach to landing speed range. Use the low end of that range and recognize that you can fly even slower if you compute Vref based on weight below gross.

 When you have completed the roundout and are in the flare, the pitch attitude should be slowly increased to raise the nose to block your view of the runway over the nose.  Psychologically this is difficult to do because of years of driving cars. You want to see the runway (road) ahead. What you must do, is spread your vision so that the horizon to each side of the nose becomes your visual reference. If the horizon rises relative to the nose you are falling and should lift and pull the yoke. If the horizon falls relative to the nose you are rising and should pause for the time it takes the nose to reposition itself relative to the horizon. Moving the yoke forward is a no-no. The limits of human recognition and reaction are such that any forward movement of the yoke will most likely make things worse. It has taken years of empirical evidence and wrecked aircraft to make this a truism of flight instruction.

To avoid flare problems you must stop looking at the runway once over the threshold and look to the far end of the runway while initially holding the nose level with the runway. As the aircraft slows deliberately raise the nose to touch the far end of the runway. Hold it there as you gradually reduce the power. As you reduce the power raise the nose still more. The ideal, seldom achieved, is to touch the ground just as the yoke is full back and the power all the way off. Don't try to see the runway hold runway alignment with peripheral vision to each side of the nose.

The psychological problem in this landing lies in the instinctive desire to keep the runway in sight. Accept the fact that a good landing requires the disappearance of the runway. You can control your height above the runway by sighting on both sides of the nose using your peripheral vision. By keeping the horizon from either rising or falling you can be assured that you are about to touchdown. A firm touchdown does not hurt the airplane as long as it is not from over a couple of feet and without any side load. This landing means that the aircraft is through flying and will not rise again into the air. Continue to hold the yoke full back until the nose wheel falls of its own volition.

In a full-stop landing most pilots are advised not to do any post-landing cockpit changes until clear of the runway. Exceptions to this might be where your approach speed requires braking that would damage the tires unless removal of the flaps would increase weight on the surface.

Watching landings
I spend my time waiting at an airport watching landings. I know a high percentage of accidents occur during landings but that is not why I watch. Rather I try to determine how many 'practice' landings are really bringing improvement or changes. Most landings seem to include the nose wheel in the touchdown. Fewer than half appear to be stabilized on final. Frequently speeds are so fast that much of the runway is consumed in float. A bounce is usually followed by another bounce. The go-around is just not utilized as part of a poor landing. The concept of a good landing seems to be the smooth 'greaser'. In reality, a good landing is on the aircraft mains and 'firm' and slow enough on ground contact that the aircraft will not fly again.

Patterns another FAA way. Maintain cruise speed to the key position. Then cut your power and hold altitude as you decelerate. When you reach your approach speed you turn base. When lined up with the runway, turn final. You will be on final carrying whatever power level you initially set at the key position. I don't understand why there is no mention of trim

Continue To Next Page

 


Copyright 2003-Now www.airman.us All rights reserved. Reproduction in any form is prohibited.