turning

Angle of Attack (AOA)

Your learning progress is directly related to your understanding of how the controls affect flight. Accidents are the ultimate solution of a lack of understanding. A pilot must understand the function of the rudder and angle of attack related to flight. By definition, the angle of attack is the angle made by the chord line of the wing and the aircraft flight path. At a certain critical angle of attack a wing or a part of it will stall regardless of speed or load factor. Stall warners are used because AOA indicators are difficult to install on small aircraft and even when installed the AOA at stall varies however slightly.

A wing can produce lift by increasing the AOA until reaching the stall AOA. AOA is controlled by used of the elevators. Any increase in speed will increase the lift. In straight a level flight lift is equal to aircraft weight. The fact is, airspeed does not cause a stall, AOA causes a stall regardless of speed or load factor. Load factor can be increased by turns, abrupt control movements and dive recoveries. In these instances the aircraft may stall at a higher speed because of the load factor but the AOA is always the same. Load factor 3.8 corresponds to load factor needed to maintain level flight in a 74.7 degree bank.

There is a relatively wide range of level flight speeds. A pilot can by varying power and AOA, one against the other, transition through all the level flight speeds. A fixed power setting and AOA allows a pilot to trim for a hands-off airspeed. Changes of power only in a hands-off flight situation will cause the aircraft to change the nose, up or down, and, with dampening by hand, the aircraft will climb or descend at very near the original speed.

There is controversy between the aviation guru Wolfgang Langewiesche and the FAA as to what flight controls do. Regardless, to place the aircraft into a given position the same essential movements are required. Elevators do control the angle of attack and in so doing they control airspeed. Elevators do not 'elevate' the aircraft except by converting excess airspeed into altitude. The primary factor used to 'elevate' an aircraft is excess power. The landing process is best stabilized by setting constants. Power is the first and easiest constant to set. With power set the elevator becomes the speed control and trim is the 'lock' that will set a constant speed. Once a locked constant speed is attained, small power reductions can be used to control the glide path descent. Maximum power is used to intercept a higher glide slope.

Controls and What They Do

When engineered, an aircraft will have controls that are designed to give a 'feel' of solidness. This design is there to prevent over control. Almost any aircraft can be torn apart but too abrupt control movement. This is why knowing the Va speed is so important to a pilot. Aircraft controls by design try to warn the pilot of potential dangers by providing feedback. Every control movement gives the pilot a 'feel' for what the aircraft is doing. Designs for differing purposes set the control force required for a given manoeuvre.

Designers try to harmonize the control forces around the three axes. The standard control force rations are 1:2:4. The roll axis force is 1. The pitch forces are 2 or twice the roll axis required force. Rudder forces are 4 or twice the pitch forces required. The axes are the basic elements. The placement of controls and their required forces are built around the force capabilities of the human body.

Since the movable control surfaces are distant from the pilot, the use of rods, cables, chains, and associated levers, pulleys, hinges and horns are needed to provide the connection and desired movement. An unwanted factor in this connection is friction. Frictional forces have a negative effect on a pilot's ability to trim and stay trimmed. Friction can be the subtlest force faced by a pilot. When trimming and staying trimmed becomes a problem, suspect friction as the culprit.

The 'feel' on the controls is proportional to the airload on the control surface. A control has a neutral or trimmed condition in normal flight. The further from this condition the surface is moved by the pilot, the greater becomes the control force required. This occurs even at slower airspeeds. Control 'feel' is a tactile pilot indicator to be added to wind noise, propeller beat and engine sounds as an airspeed indicator.

Student pilots must be taken through basic manoeuvres so as to learn by experiment how control force feels. Once these forces and their changes have been experienced they can easily be transferred from aircraft to aircraft just as we do with automobiles. Once you learn to fly smoothly in one aircraft you can learn quickly to fly in another. Engineered force-feedback is basic to all aircraft design. A pilot does not watch the yoke move; he feels the movement and the pressures.

Feel and movement of the controls can be altered in an aircraft. Spades, servo tabs, counter weights, springs and aerodynamic design are commonly used by engineers to affect changes. Size, strength, and placement are used to reduce some of the forces required by the pilot. From a given trimmed condition every control requires an initial force to make it make its initial move. This beginning force is called 'breakout'. If this required force were not there it would be impossible to fly smoothly while holding a control. With 'breakout' force required a plane's controls will only move when intentionally forced past the 'breakout' pressure. The 'breakout' force is a very carefully selected item of control. It must be there to prevent the unintended pressures and yet allow very small-intended pressures to have effect.

The primary controls are the elevators, ailerons and rudder. These provide primary movement around the axes of flight. In combination, they give coordinated movement around the axes of flight. Engine power is an additional primary control of pitch. Again, in combination, it gives coordinated movement. No change in one axis occurs without having some effect on the other axes.

Secondary controls include trim and flaps. Devices that augment engine power and control operations, weight, centre of gravity and load factor have secondary effect on control. Complex aircraft may have additional controls. The effect on all controls is dependent on conditions of altitude, speed, temperature and weather.

Neutral pitch is engineered into the placement of engine, wings. horizontal stabilizer and loading limits. The pitch is moderated to a designed degree by elevator, engine power and trim. Any change in elevator or engine power along with the rapidity of change requires coordinated control movement in the other axes. To change only pitch, by whatever means, some additional combination of rudder and aileron is required.

Ailerons "control" bank angle, roll and roll rate but, in combination with the other controls. On application of aileron in a turn, rudder must be "coordinated" to keep the tail behind the nose; elevator is used to counter loss of vertical lift. Ailerons work in opposite directions, usually in differing distance and with an effect called adverse yaw. The down aileron gives lift and drag (induced). The drag resists the turn so that rudder is applied for coordination.

Rudder is used most often in anticipation of known requirements from the other controls. Rudder will induce roll as well as yaw. The rudder can be used to raise a wing in a stall. Anticipatory rudder is applied to counter the effects of power/pitch applications. A rudder applied yaw is used to make possible crosswind landings. P-factor, torque, precession and slipstream all require use of the rudder. Skilful rudder on the ball and in anticipation is the distinctive mark of a good pilot.

Power is a pitch control. Just adding power (no other control input) will cause the nose to rise and roll to the left. Speed will decrease. In a turn, power will make the left turn possible with little or no rudder but require rudder to "lead" the right turn. There are countless cause/effects in the creation and control of a given airspeed and pitch condition.

Anticipation

The ability to anticipate changes in control pressures required for a particular manoeuvre must be developed. Failure to anticipate rudder movement required to move the nose as airspeed decreases is a most common flight error. The behaviour of instruments such as the airspeed indicator and vertical speed indicator that lag in relation to sound and attitude changes must be expected and understood. Chasing the airspeed indicator is a common student fault. Even worse is not recognizing that the VSI (vertical speed indicator) takes about 12 seconds before giving accurate indications unless the control movements are exceptionally smooth. Starting the trim from a known position and keeping track of its movements in various flight configurations makes possible rapid/correct trim pressure corrections.

Practice of the right kind makes perfect
Don't begin a manoeuvre until the aircraft is in stabilized flight.
Start over if a manoeuvre starts wrong.
Don't practice making mistakes.
Self-evaluation is a part of the process

Be willing to seek advice.

Holding Headings

A pilot (not a student) is expected to hold a heading. The PTS allows a + 10 degree or 20 degree range. It is a mistake to be accepting of this range. Successful flying is most dependent upon acquiring and holding a heading, not a range of headings. Success in holding a heading is dependent upon a pilot's ability to 'hold' the yoke in one position while attention and movement is directed elsewhere. It doesn't come easily or cheaply but it is there to be achieved. Rudder alone will do the best job.

Turning to a heading is another much sought skill. The variables in a turn far exceed those in level flight headings. The turn has the angle of the bank, anticipation of yoke pressures, and airspeed as a factors. The quality of the turn is measured by the pilot's ability to determine when to begin rolling the wings level, when to stop at level and most of all how to keep it there during the transition. For every degree of bank and airspeed we must learn what to do and when to do it.

Other opinions to the contrary, the thirty-degree bank is the safest and most controllable bank. The turn can be cleared and completed in a minimal time. The established bank is quite stable in comparison with others. Making a standard bank procedure develops a sense of turn time and direction that is easily adapted to airport patterns. This stability can be demonstrated by entering a 30-degree bank, putting in about 1/2 turn of trim to hold the nose and then holding the bank with light rudder. It will hold both bank and altitude better than in any other banked condition.

The preferred method of recovering from a bank to a selected heading is to begin recover at half the number of degrees in the bank. A thirty degree bank's recovery will begin at 15 degrees before the desired heading. These markings are easily observed on the heading indicator. With some adjustment in the recovery rate this method will work for all banks. In the real instrument (IFR) world the standard-rate turn (3-degrees per second) recovery can be done quite quickly without regard to any rule.

Oh, that right rudder

A pilot should not assume that yawing tendencies caused by attitude, P-factor, gyro effect and lift are limited to tail draggers. Any correctly flown single engine propeller driven aircraft will respond to these factors and effects. Just how much response is noticeable depends on airspeed and power applications. The left turning tendencies in airplanes is a part of their nature. The pilot must learn to anticipate changes in these effects in use of the right rudder. Reaction will always be too late if not too little. Try holding the nose straight with the rudder momentarily while rolling into a 30-degree bank. to do this you must keep your eyes outside the cockpit and watch the nose. Establish the bank and hold it with the ailerons.

Propwash

The air flow from a propeller swirls like a corkscrew around the fuselage of the plane. It curls across one wing differently than the other and into the vertical stabilizer and rudder from only one side unless there is one below the fuselage. In a C-150 the left wing will have a higher angle of attack than the right. Higher angles of attack create drag. The prop wash hits the left side of the vertical tail components. Because of prop wash the rudder is the first on your controls to become effective. In low speed high power situations your rudder is the most effective control you have. Both of these effects contribute to the left turning tendency of an aircraft. The pilot must counter these effects by anticipating use of the right rudder.

Propeller

The propeller has 80% efficiency. This efficiency exists only at the designed cruise speed, which is often faster than the L/D and fuel efficiency speed. A constant speed propeller is most efficient as RPM is at or slightly below manifold pressure. A propeller is most efficient if the leading edge is rounded smoothly and the trailing edge is squared.

P-factor

The arc that a propeller makes can be considered as a variable pitch disk. In a vertical plane to the horizontal the pitch of the entire disk is the same and it pulls equally side to side and top to bottom. Pitching the nose up causes the blade pitch angle on the left descending blade to increase and the rising blade on the right to decrease. The descending blade takes a larger cut than the rising blade. It is working harder and exerts more pull on the right side. The net effect of this is to turn the aircraft to the left. Some aircraft engine installations point the engine slightly to the right. The right thrust effect is used to offset the p-factor of the descending blade. Usually the pilot must anticipate P-factor with applications of right rudder.

Torque

On the ground the landing gear prevents your airplane's fuselage from turning but it does cause the left tire to exert more ground pressure than the right. This causes a left-turning tendency. Additionally the left wing can be set (twisted) to provide the additional lift that counters the torque effect of the propeller while in the air. This wash-in amount is most effective at cruise. In low-speed-high-power situations the pilot must add right rudder.

The Gyroscopic Propeller

Pitching of the nose causes yaw, and yawing of the nose causes pitching. As mentioned before the propeller is a spinning disk and has all the effects of the toy gyroscope you see in stores. Just by pitching up you can cause the plane to yaw to the left. Yawing the aircraft back and forth with the rudder will cause the nose to vary in pitch.

Level Dynamics

When a pilot has his aircraft flying so that the amount of propeller thrust is equal to the drag and the wing lift equals the weight plus the negative lift of the tail surfaces he is in level flight. The weight will always be focused to the centre of the earth. Up to the wing's critical angle of attack an aircraft and power available will be able to maintain level flight over a wide range of speeds. When the aircraft is flying slowly drag is mostly induced drag. At high speeds drag is mostly parasitic drag.

Levelling Off from Climb

The student should know for levelling off from a climb at Vy will require a certain amount of anticipation, a certain amount of trim, a certain amount of acceleration, changing amounts of yoke pressure, a power adjustment, changing sounds and some fine tuning. The trick is to put the aircraft into the desired attitude and leave/keep it there.

Unable to fly level

After you have been flying a while either with the instructor or solo a common phenomenon seems to occur where the new pilot is suddenly having difficulty in levelling off. This is normal. As we have trained and practiced we have developed along with the procedures for levelling a set of references. We may have started with the wing on the horizon and gradually been able to reference the nose to the horizon. Now, it doesn't seem to work. We may oscillate in altitude, airspeed and trim for several minutes and still not get it right. It is going to happen.

The reason it this occurs may be due to one factor or a combination of factors. If the weather changes so that your usually clear horizon is blocked by haze or cloud formations you have lost an essential reference. Flying in mountains where the horizon cuts through the mountains can be a causal factor. Perhaps due to a distraction you forget to trim. Power control can cause the aircraft to fail to accelerate or to exceed cruise speed. Any one of these or a combination can cause levelling off problems. You might practice making deliberate errors in your levelling off procedure to ascertain the corrective procedure that works for you.

Most of the small movements evade detection of the eye but are sensed subconsciously by the peripheral vision, dangerously so. In certain pattern turn conditions the peripheral vision can deceive your brain as to the true attitude of the nose.

On Making Turns

The aileron into the roll in and out must be smooth and blended with the use of rudder. Such a bank is unique in that when reached and held there the yoke will be parallel to the cockpit panel just as in level flight. the 30-degree bank is very stable and can be held there with light rudder pressures. There is only .15 G difference between level and the bank G-forces. The 30-degree bank feels good when done right and held there.

There are distinct differences between left and right 30-degree banked turns. In a Vy climb a turn to the left may well not require any additional rudder pressure except when rolling out. The entry into a right bank from a Vy climb will require leading with the rudder, holding it into the turn and relaxing it during the roll-out. These uses of the rudder are not intuitive and exist to a slight degree even in level and descending flight.

The rigging of the aircraft is a variable factor that accounts for the need of pilots to adjust to each aircraft. The making of 30-degree banks is useful as a maximum limit in the pattern because it makes the turn quickly into the cleared area. A more shallow bank is useful if a higher rate of climb is required as in making a 270 departure. ATC prefers the 30-degree bank to the 20-degree bank because it is less likely to be confused with a wing wobble. 30-degree banks can be checked with both the attitude indicator and the Cessna wing strut being parallel to the ground or horizon.

In making turns there are two criteria that are used around the pitch axis. In level flight it is the altitude and in climbs and descents it is airspeed or rate of descent. The indicator in both cases is the nose and sound. 30-degree banks do not require much pressure but the application an removal of that pressure must be done in anticipation of what is going to be happening.

On rolling into the turn you apply pressure with the forefinger and hold it until beginning to roll out. At this point you apply thumb pressure because the increased lift in level flight always causes a pitch-up unless anticipating counter pressure is applied. The usual rule for rolling -out on a heading is to begin at half-the-angle-of-bank. Students should be encouraged to watch the nose during turns with only quick glances at the heading indicator for the lead-in heading used for rollout. The final heading should be initially acquired by watching the nose. Any fixation on the heading indicator prior to or after roll-out will generate wing wobble. Precise turns are a matter of consistency in the roll-in and the rollout.

Why Turns Turn

A turn is a combination of several aerodynamic factors. Individually each factor has both positive effect and negative effect. Beginning with the ailerons the inside aileron goes up and decreases lift that lowers the wing while the outside aileron goes down and increases the lift that raises the outside wing. We now have roll. Along with raising the wing the outside aileron just by increasing the lift also creates drag. Parasitic drag that is. This drag is a negative that tends to swing the nose away from the turn. This is yaw... Adverse yaw, that is. The combination of roll and drag is called coupling. With roll you get yaw. The speed or rate of your roll entry, by affecting the relative winds of the two wings, causes additional but slight adverse yaw.

Without coordinating rudder to counter any adverse yaw the aircraft is in a slip. The lower wing is faster and moving forward and rising with the increased lift. The relative wind weakly moves the vertical stabilizer away from the turn effectively moving the nose into the turn and reducing the slip.

Coordinated rudder solves all the dynamic equations of the turn. It eliminates adverse yaw and all the forces that reduce roll effectiveness. the rudder must be applied or even anticipated at the beginning of the roll and then pressure reduced once the aileron deflection is reduced. The roll-out to heading reverses the roll-in process. Turns are more enjoyable when the proper rudder forces are applied.

Level Turn Dynamics

A banked aircraft transfers some of the available wing lift away from the vertical into a turning force. It is this transfer of lift that makes it necessary for the pilot to increase the wing's angle of attack to obtain the lift required for maintaining a constant altitude. In this bank there is an apparent increase in weight caused by the horizontal centrifugal forces of the banked turn. At a 60-degree level altitude bank the weight of everything is doubled. (2 G's) A 30-degree bank has an effective weight increase of .15 Gs.

Since the most likely C-150 mid-air will come from a faster aircraft from the rear quarter, always look beyond 90 degrees when clearing but any aircraft above the horizon will pass overhead. Any following aircraft should pass to the right, initiate clearing turns to the left. There is nothing wrong with raising the wing for clearing. The instinctive desire to see around the wing in the direction of the turn is both dangerous and inefficient. You can't really see and you decrease your ability to hold both bank and airspeed. Keep your eyes on the nose and horizon during a turn. Don't turn into an area you have not cleared. Do not pull back on the yoke to recover from a turn or bank, use the ailerons.

Bank Recovery to a Heading

Lead your recovery from a left bank by applying right rudder. Lead your heading recovery by 10 degrees in a 20 degree bank, 15 degrees in a 30 degree bank and 22 degrees in a 45 degree bank. Every recovery from a bank also requires that some forward pressure be applied to prevent the 'pop-up' airspeed loss that will occur as the wings acquire added vertical lift when levelled.

Level Turns

The turn is the only of the four basic manoeuvres that exists in conjunction with the other three. The level turn is a balanced condition, as with level flight, where the lift equals the aircraft weight. With constant power the airspeed and angle of attack are controlled with the elevator. Some airspeed is lost during the turn due to an increase in pitch. The rudder keeps the tail behind the nose. The quality of the turn is a blend of yaw, roll, pitch and power. The blend is changed as the angle of the turn increase or if it occurs as level, climb or descent. A climbing or descending bank requires a different blending of these factors.

Elevator controls pitch. Elevator trim is for removing control pressures when a prolonged flight condition or attitude is to be maintained. Entering a 30 degree bank requires slightly forward yoke input on the elevator with the thumb. This prevents excessive loss of airspeed. On reaching 30 degrees a slight back pressure with the finger will give the pitch needed to maintain altitude. Recovery from the bank requires slight forward pressure with the thumb again. These finger applications are more pressures than movement. If the turn is to the right, rudder pressure precedes aileron movement. Recovery from a left turn requires that right rudder pressure precede aileron movement.

The only control difference between the left and right bank is the anticipation and lead required on the right rudder. You lead the right turn with right rudder perceptibly before you need to with the left rudder in a left turn. Again this is because of aerodynamic factors . Likewise, the recovery from the left bank requires anticipation and leading with the right rudder before levelling off. In this instance forward pressure is required to prevent the 'pop-up' from causing an altitude gain when levelling off. The steeper the bank the greater the need for knowing about the amount of anticipation and firm forward pressure required.

The design of most light aircraft gives a stable 30 degree bank hands off with just a little nose up trim. The aircraft will tend to level off from any bank less than 30 and become steeper from any bank more than 30. At 30 degrees the G-force is +1.15, at 20 degrees the G-force is 1.06, at 45 degrees you get +1.41 G, at 60 degrees the G force is +2.0. Aileron must be held into the bank at less than 30 degrees, against the bank at more than 30 degrees and neutral at 30 degrees. Any time the ailerons are not neutral there is induced yaw which must be countered by rudder. Adverse yaw ceases when ailerons are neutral.

A similar manoeuvre will work with most any G.A. plane but the amount of trim will vary. A bank of less that 30 will cause the aerodynamics of the plane cause it to want to level off. Yoke must be held into the bank. A bank of more than 30 will cause the plane to want to continue on over. The yoke must be held against the bank to keep the bank from increasing.

Climbing Left Turns

All turns that are going to exceed the angular range of windshield vision should be preceded by "clear R/L, Turn R/L" Failure to clear will fail any flight test.

Since there is increased P-factor present in a climbing left turn, some right rudder might be required throughout the turn to keep the ball centred.. Even more right rudder will be required when levelling off. The aircraft will tend to lose some indicated airspeed when all turns are initiated. A slight, almost imperceptible forward pressure with the thumb will prevent this indicated speed loss. As soon as the 30 degree bank is reached the thumb pressure is removed and replaced by sufficient one finger pressure to maintain both bank and airspeed.

In addition to P-factor that exists in a climb, in a climbing turn we introduce yaw. Yaw in a turn is caused by drag. Drag, in turn, is produced by a higher angle of attack. The high wing in a turn has more yaw and more induced drag and a higher angle of attack because of the down aileron. The fact that it is moving faster is a minor but existing parasitic drag factor. It is the initial induced drag of the aileron's greater deflection when rolling in and out of banks that increases the need for more rudder

Climbing Right Turns

Right rudder pressure is being held in the climb due to P-factor. Even more is now required to initiate the right turn. Anticipate the need to lead with right rudder in making right turns. Yoke pressures and anticipation is much the same as with left turns. Recovery from the bank requires only that the right rudder pressure be relaxed and then reset for P-factor to climb on heading.

Steep Turns

At some point during the first four flights steep turns should be demonstrated by the instructor. You should use a prominent visual reference on the nose at a cardinal altitude. While the PTS (Practical Test Standards) requires only one 360 degree turn, the most instructive steep turn consists of two full 360 degree turns, 45 degrees of bank, a constant altitude, and cruise power. The bank entry to the 45 degree steep turn should be smooth and rapid. Initially check the angle of bank on the horizon against the attitude indicator. Once the angle has been achieved concentrate on the horizon and its angle. Variations of five degrees of bank may be used to control altitude. The new PTS requires only one 360 degree turn with recovery near heading.

After clearing, enter the steep turn smoothly and rapidly, lead with right rudder if to the right. Sight on the horizon and anticipate the loss of lift with a locked elbow on the door and sufficient back pressure to prevent a loss of altitude. Angle of bank may be varied from 45 + 5 degrees to adjust altitude. Using the elevator to adjust altitude gives only an illusion of change. Actually the turn is being made steeper with a resulting loss of altitude, increase in G-forces, airspeed and angle of attack.

Steep turns are precision manoeuvres flown as a confidence builder. The vertical lift lost by the steep bank must be replaced by increasing the angle of attack by applying back pressure. The seemingly great pressure required is because of the increase in G force due to the bank. The critical angle of attack of the wing remains the same but due to the increase in weight (G-force) the stall occurs at a much higher speed. (A stall in this situation is called an accelerated stall because of the higher speed.) Rudder is used to compensate for drag /adverse yaw from the raised wing. Once in the turn, the raised wing will travel faster and provide more lift. To compensate for this lift caused over banking tendency the ailerons must be held against the bank.

The steep turn, properly performed as to bank and altitude, will, as the second 360 degrees of turn are performed, come in contact with the wake turbulence of the previous 360 degree turn. This second 360 is no longer required by the PTS (Practical Test Standards) but it is the best way to self check performance of the manoeuvre. Encountering the wake will cause the wings to rock and maintaining altitude typically becomes a problem. The initial surprise seems to be the cause. The student will instinctively relax pressure when it should be held or increased. If more than 100 feet is lost the process should be started over from the beginning. Since the bank is 45 degrees the levelling off should begin about 22 degrees early. A very positive forward pressure must be applied to prevent a pop-up increase in altitude. The turns should be performed both left and right but perhaps at different time since they may cause student distress.

There are two distinct ways the steep turn may be performed, with or without trim. The unexpectedly high yoke pressures required to hold both the bank and the altitude is difficult for students but very instructive. They should learn to press their arm against the door to lock the pressure and position. The second way is easier but requires some timing. Airline instructors do not allow the use of trim. At the moment the 45 degree bank is attained, give the trim wheel two quick full turns down. This will release almost all of the pressure required to hold altitude. Now most of attention can be devoted to bank angle and the slight changes needed for altitude. The yoke release often caused by the surprise of wake turbulence will be compensated for by the trim setting. However, when levelling off the trim must be removed very quickly before it aggravates the typical pop-up pressures of levelling off.

First: go as quickly into the bank to 45 as you can in both methods. Easy way: Using the tip of your right forefinger quickly make two top to bottom of the trim wheel. Now a light touch will keep you in the bank and at the same altitude. Lead your recovery by 22 degrees and again quickly remove the two turns of trim with your finger tip. Do not pinch the trim wheel.

Steep Turns (Basic)

Pressures keep changing in the steep turn your coordinated aileron and rudder, back pressure, all changing to opposite aileron and reduced backpressure when established at a constant airspeed. If you have gone smoothly to slightly over 30 degrees and held some back-pressure the normal over-banking tendency of the aircraft will wind up at the desired 46-degree angle. It will take opposite aileron to keep it there.

The plus/minus ten-knot speed allowance can be set up either entering the turn or after the turn is established. Enter the turn and add some power in anticipation of a loss of speed. Another way is to wait until the turn is established and then add a predetermined amount of power to stay within the allowance.

The vertical speed indicator is the rabbit to be watched. The slightest movement up or down is a warning of altitude changes soon to follow. The VSI is a more important instrument than the altimeter is during a steep turn.

The recovery from the steep turn is based upon the half-angle recovery method but must be followed by abrupt forward yoke to prevent a sudden increase in altitude. Watch the VSI and lock your elbow.

Steep turns (Complex)

A method is to use additional power to maintain altitude.
Determine in flight the descent rate at a given bank angle when not maintaining altitude.
Add 1" of MP for every 100fpm of sink to maintain altitude.

Technique works only from something less than cruise speed. A good entry speed would be a holding speed or approach speed. Add the throttle smoothly when rolling in the bank and reduce throttle when rolling out.

VSI in Slow Flight and Steep Turns

Slow flight and steep turns are areas where a pilot would do well to pay more attention to the VSI. The VSI is a very good precursor of altitude loss. By watching the VSI a pilot will be able to anticipate the need for power sufficient to prevent any descent. In slow flight every change in power should be accompanied by proportionate rudder pressure. In the steep turn you can use the VSI to get the yoke pressure back or forward to prevent altitude excursions.

Impossible Turn

Popular wisdom is that a pilot should never turn back to a runway on takeoff. An even older wise axiom is, Never say Never". Studies of the most likely to succeed turn back to the runway is the one that is into the wind at 45-degrees. The requisites are that the turn be coordinated, smooth and on airspeed.

This manoeuvre must be practiced at altitude until performance meets the highest standards of angle, airspeed and smoothness. Lack of coordination will cause a stall and spin entry. Only practice of the right kind will prepare a pilot for low level performance.

The Vy climb speed used for takeoff is very nearly the same as the standard approach speed and the 45-degree steep turn stall speed. The stall margin requires strict attention to the performance of the turn and foregoing ground proximity awareness. Success means survival. You will not be able to get back to where you lifted off. You may be able to reach the departure end of the original runway. This is better considering you will have a tailwind. Anything over a ten-knot tail wind would negate making the 'impossible turn' possible. Crosswinds, crosswind runways, and local factors can change your options.

Graveyard Spiral (Hood)

This is a slow turn that will gradually increase in bank angle because of the lift differential between the inboard and outboard wing. The pilot does not need to apply any input. Bank angle increases result in the nose dropping and speed increasing. An aircraft can be expected to have the wing fail upward and forward under the positive-G overstress of this situation. However, if the speed is greater than 15% of the Vne the failure may be downward and aft. Flutter causes this type of failure.

Blind Canyon Turn

The infamous "blind canyon 180" can get you into a mess of trouble if you don't have a complete understanding of minimum radius turn theory. Just hauling back with full power isn't the whole story here by a long shot. You might not have the room to make it using a level turn. First of all, the stall speed increases by the square root of the load factor x the wings level stall speed as bank is increased, so if you have a stall speed of 60kts wings level, you will pay off at 85kts in a 60 degree bank. And this is just the beginning of the story. There is also a specific airspeed where minimum radius, best rate, and maximum available g can be married to produce an optimum turn. In fighters, we call this corner velocity or corner speed.

For a typical general aviation light airplane, this speed can be found at the intersection of the aerodynamic limit and limit load factor lines on a v/g diagram. It loosely translates to your Va or manoeuvre speed. Remember, this all applies to level turns. It's possible to reduce the turning radius even more than this by using the vertical plane in the turn. Again in fighters, we call this a high yo yo. You can consider it a wingover. By raising the nose and bleeding off airspeed, then allowing the nose to come through the turn with maximum bank unloaded, you can severely reduce the horizontal turn radius for the turn. There is a level of performance even above these manoeuvres that is possible with aerobatic training, even if performed in a normal category airplane. If performed properly by a trained pilot, a hammerhead turn will produce an absolute minimum radius 180 by using the vertical plane almost entirely to reduce the horizontal turning component to near zero. This would be considered an emergency procedure in a normal category aircraft, although it can easily be done within the allowable load factor limits.

The bottom line on blind canyon turns is this. Don't get caught in this situation in the first place, but if you fly in terrain where an emergency maximum performance turn could save your life, go out and get some competent instruction in these procedures.  .Just yanking it around with power isn't the way to go!

The Pirouette Turn

Pre-decisions are credited by accident survivors as having much to do with their success. The pirouette, pivot turn, is an emergency escape procedure as a last option when you have run out of aircraft performance and turning room. The entry into this situation requires a continuous series of bad decisions. Even then the pirouette will not be of help unless you have practiced to proficiency. An incorrectly performed turn will only make a bad situation worse. This means you must practice it. More importantly, the pilot who understands the factors leading to will never need to make the turn.

The pirouette turn allows a 180-degree turn with a minimum radius and no loss of altitude. This is a maximum performance turn required when you have run out of performance. The procedure is to reduce to idle power, put in full flaps and maintain wings level. Then before you begin to sink you put in full power, pitch up the nose and kick in full left rudder. Milk off the flaps.

The aircraft will have made 180-degrees of turn faster than you can say what to do. It is most effective to the left. But could be done to the right if you did not add power. The bank angle should be shallow enough to avoid a stall but steep enough to minimize the turn radius. It is my opinion that this manoeuvre could be practiced at altitude but perfected at real or simulated high-density altitudes.

Normal Bank Attitudes

Zero bank for level flight
Shallow bank that requires yoke pressure into the bank to remain constant and prevent levelling.
Medium bank that can be flown without any yoke pressure but requires trim to hold altitude
Steep bank that requires yoke pressure against the bank to prevent increasing angle.

Takeoff Emergency Turn Revisited

Make the turn at stall speed + five knots based upon weight and POH.
1.3 times stall speed takes larger turn radius.
Practice the turn at altitude at stall speed to get height you need for turn-back.
Allow four seconds for decision making
On average use a 225-degree teardrop back and 45 degree alignment series.