Power-off Accuracy Landing (PTS)
A power-off landing is not a power failure emergency. The power-off landing is a procedure that can be flown to a normal landing. The beauty of teaching the power off landing as a normal procedure for a normal landing is that an actual engine failure can be dealt with as a non-emergency. There is a certain amount of guesswork involved. The pilot must make adjustments determined by wind velocity and direction. Flaps are not applied until the field is 'made' if at all. It is best to arrive with excess altitude that can be removed by a slip. Any effort to stretch the glide by increasing the angle of attack will only provide a brief reduction in descent rate soon followed by a reduction in ground speed as though by a headwind.
Up until the late 1960s the PTS normal landing was made with power-off. Once abeam the numbers the power was reduced to idle. The pilot set up his constant airspeed glide. Speed and descent was adjusted throughout turns from downwind, base, and final. This method of landing had a shortcoming that arose when the pilot misjudged his approach and was coming up short. On such occasions the necessary power might not be available. This could be caused when the throttle was applied aggressively so as to load up the carburetor and engine so that it would flood and quit. The power-off approach can shock-cool an engine. Before making such a landing you can pre-cool the engine by flying a reduced power prior to taking the power off. A pilot who learns to land this way will learn how to use indicated airspeed, ground speed, wind and direction to control the arrival.
After 1970 the partial power approach and landing became the approved FAA method. Still every pilot should practice and become proficient making power-off landings. The process is just as years ago, except that it is accepted procedure that the pilot may 'clear' the engine during the approach to assure that available power is there. There is no reason that the power-off landing cannot be accomplished as efficiently as a partial power landing.
Every landing is guesswork. Ideally the pilot creates as many constants as possible. The available constants consist of power, airspeed and flaps. With power off as a constant the pilot will fly a tighter pattern. Airspeeds faster or slower than the normal approach speed allow some variation of the glide slope. Flaps can be augmented by slips to increase the rate of descent.
Every pattern must be adjusted by the pilot through consideration of wind effect. The pilot must learn that a glide cannot be 'stretched' by reducing the rate of descent. Any variation or indicated airspeed removes the predictable constant that a stabilized approach relies on. The ideal power-off landing is an accuracy landing. This means that the touchdown must occur past a given point but within 200'. The power-off accuracy landing is a part of the private pilot practical test.
During the flight test the examiner can be expected to pull the power and advise you to make a power off landing within 200 feet of a specific point on the ground. Since you are always expecting such an event it comes as no surprise. You already know the wind, don't you? You quickly determine whether to make a 90-degree, 180-degree, or 360-degree approach with adjustments a required. You also know that two full trim turns down with the power off will give you a glide speed of 60 knots, hands-off. Just as in any constant power approach, the power-off approach speed is for a trimmed 60 knots.
At a constant glide speed, you will be able to sight over the nose to the runway and determine whether you are high or low. You have done this many times with 1500 rpm. Power off is no different. It is your intention not to apply any flaps until you know you will reach the field, so your no-flap approach will be relatively flat and high/low somewhat more difficult to assess. Every time the runway threshold passes under the nose as you fly 60 knots, you will apply a notch of flaps. Only the straight-in approach or final limits your ability to adjust base for being low or high. If your anxiety has kept you too high go into an extreme slip at 60 knots indicated to get down.
Never dive for the runway. As you know, you can extend your glide distance by removing flaps. Don't do this below 400 feet unless you are over a paved two mile runway, except in an emergency. Get your maximum flaps-for-wind-conditions in before 200 feet AGL. You will need the altitude to assure complete control in the round-out, flare, and touchdown. Don't sacrifice a good landing in your desire to hit a touchdown point. At 60- knots you will still have 200 feet of float within five feet of the ground. Use it. Always practice using ground effect in every landing. You never know when you will need the skill and experience.
Slip Landings
Any time the plane is into the wing low and opposite rudder configuration forward pressure will be required on the yoke to maintain the approach speed. The advantage of a constant airspeed is that rudder pressures and aircraft reactions will be more consistent. Runway alignment is maintained by how low the wing is held. Nose alignment is held with rudder. If the nose can't be kept straight with the runway with full application of rudder then airspeed must be increased to improve rudder effectiveness. If the nose cannot be held straight the landing should not be attempted. Go around and try the landing with little or no flaps.
The pilot's success in acquiring initial runway alignment is predicated on how well the turn from base to final is planned. This is a ground reference skill. Holding this alignment with wing low and rudder applications depends upon mastery of the Dutch roll. When turning from base to final or when on a long final it is quite common to find that you are not properly aligned with the runway. How you make your corrections is important. If you are obviously far off, you should do something in the order of a 30-degree intercept to final. If you are only a few hundred feet off line and still have plenty of altitude, alignment may be achieved by holding the wing extra low into the wind. If the wind is blowing toward the runway, level the wings and let the wind blow you into alignment. If you are 500' from touchdown and have not attained runway alignment make a go-around.
Being unable to acquire and maintain the wing down and nose straight alignment with the centerline of the runway is hazardous. This skill and its associated understanding is a required acquisition before doing crosswind landings. A smart pilot will make the required effort to become both skilled and safe in crosswind landings.
Since winds normally decrease in velocity at lower altitudes, a constant change in rudder and aileron pressures will be required during descent. I like to advise the student that there is one wind at 500', another at 50' and still another at 5'. This is why you must be prepared to make the constant control adjustments required.
The stabilized approach with a set power, set flap, set trim, and set airspeed will permit repeated practice of the correct roundout and flare. If even one of these becomes a variable then each roundout and flare becomes an experiment with variable success. Once in the flare, there should be NO abrupt changes. Power and yoke must be moved slowly initially and then faster logarithmically to the full off and back positions respectively. Abrupt use of either power or yoke alone will become precursors of a hard landing. The go around is the best judgment decision for any approach that is not stabilized.
The first essential of a good crosswind landing is airspeed at Vso. This slow speed minimizes all the problems that result from high speeds on touchdown. Speeds higher than Vso use more runway, require excessive braking, extend the influence of ground effect or float, and increase the bounce and porpoise likelihood. Touchdown as slowly as you can.
Secondly, the touchdown point is in the first third of the runway. A stabilized approach at the correct airspeed will give you a visual aim at the runway. If low, you add full power and hold the approach speed until you regain the glide slope. If high, you add appropriate flaps, reduce power, reduce airspeed in that order and prepare to go-around.
Third, keep the nose parallel to the runway. There is frequently a problem with the student who is concerned with landing on one wheel and the rudder pushed in. Because of this concern he releases the rudder prior to touchdown along with other control pressures. This results in many of the bad effects of the poorly executed crab landing. Both main wheels touchdown at the same time, the nose wheel hits with them. Side loads are applied to the landing gear and very possibly the aircraft weathervanes into the wind. These are all the negatives in a crosswind landing that result from directional imprecision.
Nose-wheel First
A properly rigged aircraft can be trimmed for hands-off flight. The properly rigged airplane has an longitudinal oscillatory pitch mode which once properly trimming will allow the plane to return to that first flight condition even if the nose is moved. The nose will oscillate at first as it returns to the original attitude. The plane is also subject to PIO (pilot induced oscillations) where the pilot, due to the delay in instinctive reaction, may push and pull at just the wrong time so as to amplify the movements. The PIO can only be broken by locking the elbow against the side of the cockpit.
This PIO is most likely to occur in a tricycle aircraft where the nose-wheel is allowed to come into contact with the runway with such force that the nose-strut is compressed. Instinct now takes control over the pilot's training. At moment of contact the pilot pulls back on the yoke to get the nose up. The nose strut reacts to its compression at the same time and together the nose goes beyond the critical angle of attack. Again at the same time the wing stalls and falls as the pilot pushes forward. The instinctive timing is only a second out of synchronization but that is enough to cause the nose-wheel and strut to again make a compression strike on the runway just as the pilot is trying to pull back to keep the nose from falling. If a go-around is not initiated on this second strike the nose-strut will strike even harder the third time to the point of collapse and propeller strike.
The go-around is absolutely the best option at the first sign of a nose-low touchdown. The rule is that NEVER move the yoke forward to correct being high in the flare. It is acceptable to stop any backward/up pressure but any forward pressure is most likely to result in the scenario above. Ideally, all yoke movements should be back and up.
Part of the FAA certification process is to check the designed stability and control authority of the plane. Within specified center of gravity limits an average pilot can make the plane perform adequately. Outside the specified C. G. limits or in a nose-wheel-first landing the one second reaction delay of the pilot will make things worse...every time.
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