Turn Radius
To understand the relationship between airspeed, bank, and radius of turn, it should be noted that the rate of turn at any given true
airspeed depends on the horizontal lift component. The horizontal lift component varies in proportion to the amount of bank.
Therefore, the rate of turn at a given airspeed increases as the angle of bank is increased. On the other hand, when a turn is made at a
higher airspeed at a given bank angle, the inertia is greater and the horizontal lift component required for the turn is greater, causing
the turning rate to become slower. [Figure 3-14] Therefore, at a given angle of bank, a higher airspeed makes the radius of turn larger
because the airplane turns at a slower rate.
Figure 3-14. Angle of bank and airspeed regulate rate and radius of turn.
As the radius of the turn becomes smaller, a significant difference develops between the airspeed of the inside wing and the airspeed
of the outside wing. The wing on the outside of the turn travels a longer path than the inside wing, yet both complete their respective
paths in the same unit of time.
Therefore, the outside wing travels at a faster airspeed than the inside wing and, as a result, it develops more lift. This creates
an overbanking tendency that needs to be controlled by the use of opposite aileron when the desired bank angle is reached. [Figure
3-15] Because the outboard wing is developing more lift, it also produces more drag. The drag causes a slight slip during steep turns
that should be corrected by use of the rudder.
Figure 3-15. Overbanking tendency.
Establishing a Turn
On most light single-engine airplanes, the top surface of the engine cowling is fairly flat, and its horizontal surface to the natural
horizon provides a reasonable indication for initially setting the degree of bank angle. [Figure 3-16] The pilot should then cross -
check the flight instruments to verify that the correct bank angle has been achieved. Information obtained from the attitude indicator
hows the angle of the wing in relation to the horizon.
Figure 3-16. Visual reference for angle of bank.
The pilot’s seating position in the airplane is important as it affects the interpretation of outside visual references. A common
problem is that a pilot may lean away from the turn in an attempt to remain in an upright position in relation to the horizon.
This should be corrected immediately if the pilot is to properly learn to use visual references. [Figure 3-17]
Figure 3-17. Correct and incorrect posture while seated in the airplane.
Because most airplanes have side- by-side seating, a pilot does not sit on the airplane’s longitudinal axis, which is where the airplane
rotates in roll. The pilot sits slightly off to one side, typically the left, of the longitudinal axis. Due to parallax error, this makes the
nose of the airplane appear to rise when making a left turn (due to pilot lowering in relation to the longitudinal axis) and the nose of
the airplane appear to descend when making right turns (due to pilot elevating in relation to the longitudinal axis). [Figure 3-18]
Beginning pilots should not use large aileron and rudder control inputs. This is because large control inputs produce rapid roll rates
and allow little time for the pilot to evaluate and make corrections. Smaller flight control inputs result in slower roll rates and provide
for more time to accurately complete the necessary pitch and bank corrections.
Figure 3-18. Parallax view.
Some additional considerations for initiating turns are the following:
⦁ If the airplane’s nose starts to move before the bank starts, the rudder is being applied too soon.
⦁ If the bank starts before the nose starts turning or the nose moves in the opposite direction, the rudder is
being applied too late.
⦁ If the nose moves up or down when entering a bank, excessive or insufficient elevator back pressure is
eing applied.
After the bank has been established, all flight control pressures applied to the ailerons and rudder may be relaxed or adjusted,
depending on the established bank angle, to compensate for the airplane’s inherent stability or overbanking tendencies. The airplane
should remain at the desired bank angle with the proper application of aileron pressure. If the desired bank angle is shallow, the pilot
needs to maintain a small amount of aileron pressure into the direction of bank including rudder to compensate for yaw effects. For
medium bank angles, the ailerons and rudder should be neutralized. Steep bank angles require opposite aileron and rudder to prevent
the bank from steepening.
Back pressure on the elevator should not be relaxed as the vertical component of lift should be maintained if altitude is to be
maintained. Throughout the turn, the pilot should reference the natural horizon, scan for aircraft traffic, and occasionally crosscheck
the flight instruments to verify performance. A reduction in airspeed is the result of increased drag but is generally not significant for
shallow bank angles. In steeper turns, additional power may be required to maintain airspeed. If altitude is not being maintained
during the turn, the pitch attitude should be corrected in relation to the natural horizon and cross-checked with the flight instruments
to verify performance.
Steep turns require accurate, smooth, and timely flight control inputs. Minor corrections for pitch attitude are accomplished with
proportional elevator back pressure while the bank angle is held constant with the ailerons. However, during steep turns, it is not
uncommon for a pilot to allow the nose to get excessively low resulting in a significant loss in altitude in a very short period of time.
The recovery sequence requires that the pilot first reduce the angle of bank with coordinated use of opposite aileron and ru dder and
then increase the pitch attitude by increasing elevator back pressure. If recovery from an excessively nose-low, steep bank condition
is attempted by use of the elevator only, it only causes a steepening of the bank and unnecessary stress on the airplane. Steep turn
performance can be improved by an appropriate application of power to overcome the increase in drag. Depending on the purpose of
a steep turn and the magnitude of control force needed, trimming additional elevator back pressure as the bank angle goes beyond 30°
may assist the pilot during the turn.
Since the airplane continues turning as long as there is any bank, the rollout from the turn should be started before reaching the
desired heading. The amount of lead required to rollout on the desired heading depends on the degree of bank used in the turn. A rule
of thumb is to lead by one-half the angle of bank. For example, if the bank is 30°, lead the rollout by 15°. The rollout from a turn is
similar to the roll-in except the flight controls are applied in the opposite direction. Aileron and rudder are applied in the direction of
the rollout or toward the high wing. As the angle of bank decreases, the elevator pressure should be relaxed as necessary to maintain
altitude. As the wings become level, the flight control pressures should be smoothly relaxed so that the controls are neutralized as the
airplane returns to straight-and-level flight. If trim was used, such as during a steep turn, forward elevator pressure may be required
until the trim can be adjusted. As the rollout is being completed, attention should be given to outside visual references, as well as the
flight instruments to determine that the wings are being leveled and the turn stopped.
Because the elevator and ailerons are on one control, practice is required to ensure that only the intended pressure is applied to the
intended flight control. For example, a beginner pilot is likely to unintentionally add pressure to the pitch control when the only bank
was intended. This cross-coupling may be diminished or enhanced by the design of the flight controls; however, practice is the
appropriate measure for smooth, precise, and accurate flight control inputs. For example, diving when turning right and climbing
when turning left in airplanes is common with stick controls, because the arm tends to rotate from the elbow joint, which induces a
secondary arc control motion if the pilot is not extremely careful. Likewise, lowering the nose is likely to induce a right turn, and
raising the nose to climb tends to induce a left turn. These actions would apply for a pilot using the right hand to move the stick.
Airplanes with a control wheel may be less prone to these inadvertent actions, depending on control positions and pilot seating. In any
case, the pilot should retain the proper sight picture of the nose following the horizon, whether up, down, left, or right and
isolate undesired motion.
Common errors in level turns are:
1. Failure to adequately clear in the direction of turn for aircraft traffic.
2. Gaining or losing altitude during the turn.
3. Not holding the desired bank angle constant.
4. Attempting to execute the turn solely by instrument reference.
5. Leaning away from the direction of the turn while seated.
6. Insufficient feel for the airplane as evidenced by the inability to detect slips or skids without flight instruments.
7. Attempting to maintain a constant bank angle by referencing only the airplane’s nose.
8. Making skidding flat turns to avoid banking the airplane.
9. Holding excessive rudder in the direction of turn.
10. Gaining proficiency in turns in only one direction.
11. Failure to coordinate the controls.
Climbs and Climbing Turns
When an airplane enters a climb, excess lift needs to be developed to overcome the weight or gravity. This requirement to develop
more lift results in more induced drag, which either results in decreased airspeed or an increased power setting to maintain a
minimum airspeed in the climb. An airplane can only sustain a climb when there is sufficient thrust to offset increased drag; therefore,
climb rate is limited by the excess thrust available.
The pilot should know the engine power settings, natural horizon pitch attitudes, and flight instrument indications that produce the
following types of climb:
⦁ Normal climb—performed at an airspeed recommended by the airplane manufacturer. Normal climb speed
is generally higher than the airplane’s best rate of climb. The additional airspeed provides for better engine
cooling, greater control authority, and better visibility over the nose of the airplane. Normal climb is
sometimes referred to as cruise climb.
⦁ Best rate of climb (VY)—produces the most altitude gained over a given amount of time. This airspeed is
typically used when initially departing a runway without obstructions until it is safe to transition to a normal
or cruise climb configuration.
⦁ Best angle of climb (VX)—performed at an airspeed that produces the most altitude gain over a given
horizontal distance. The best angle of climb results in a steeper climb, although the airplane takes more
time to reach the same altitude than it would at best rate of climb airspeed. The best angle of climb is used
to clear obstacles, such as a strand of trees, after takeoff. [Figure 3-19]
It should be noted that as altitude increases, the airspeed for best angle of climb increases and the airspeed for best rate of climb
decreases. Performance charts contained in the Airplane Flight Manual or Pilot’s Operating Handbook (AFM/POH) should be
consulted to ensure that the correct airspeed is used for the desired climb profile at the given environmental conditions. There is a
oint at which the best angle of climb airspeed and the best rate of climb airspeed intersect. This occurs at the absolute ceiling at
which the airplane is incapable of climbing any higher. [Figure 3-20]
Figure 3-19. Best angle of climb verses best rate of climb.
Figure 3-20. Absolute ceiling.
Establishing a Climb
A straight climb is entered by gently increasing back pressure on the elevator flight control to the pitch attitude referencing the
airplane’s nose to the natural horizon while simultaneously increasing engine power to the climb power setting. The wingtips should
be referenced in maintaining the climb attitude while cross-checking the flight instruments to verify performance. In many airplanes,
as power is increased, an increase in slipstream over the horizontal stabilizer causes the airplane’s pitch attitude to increase more than
desired. The pilot should be prepared for slipstream effects but also for the effect of changing airspeed and changes in lift. The pilot
should be prepared to use the required flight control pressures to achieve the desired pitch attitude.
If a climb is started from cruise flight, the airspeed gradually decreases as the airplane enters a stabilized climb attitude. The thrust
required to maintain straight-and-level flight at a given airspeed is not sufficient to maintain the same airspeed in a climb. Increase
drag in a climb stems from increased lift demands made upon the wing to increase altitude. Climbing requires an excess of lift over
that necessary to maintain level flight. Increased lift will generate more induced drag. That increase in induced drag is why more
power is needed and why a sustained climb requires an excess of thrust.
For practical purposes gravity or weight is a constant. A vector diagram shows why more lift is necessary during a climb, as the
vertical component of lift generated from the wings is no longer perpendicular to the wings and adds to drag. The total vertical force
is increased by adding a vertical component of thrust from the powerplant, and the power should be advanced to the recommen ded
climb power. On airplanes equipped with an independently controllable-pitch propeller, this requires advancing the propeller control
prior to increasing engine power. Some airplanes may be equipped with cowl flaps to facilitate effective engine cooling. The position
of the cowl flaps should be set to ensure cylinder head temperatures remain within the manufacturer’s specifications.
Engines that are normally aspirated experience a reduction of power as altitude is gained. As altitude increases, air density decreases,
which results in a reduction of power. The indications show a reduction in revolutions per minute (rpm) for airplanes with fixed pitch
propellers; airplanes that are equipped with controllable propellers show a decrease in manifold pressure. The pilot should reference
the engine instruments to ensure that climb power is being maintained and that pressures and temperatures are within the
manufacturer’s limits. As power decreases in the climb, the pilot continually advances the throttle or power lever to maintain
specified climb settings.
The pilot should understand propeller effects during a climb and when using high power settings. The propeller in most airplanes
rotates clockwise when seen from the pilot’s position. As pitch attitude is increased, the center of thrust from the propelle r moves to
the right and becomes asymmetrical. This asymmetric condition is often called “P-factor.” This is the result of the increased AOA of
the descending propeller blade, which is the right side of the propeller disc when seen from the flight deck. As the center of propeller
thrust moves to the right, a left turning yawing moment moves the nose of the airplane to the left. This is compensated by the pilot
through right rudder pressure. In addition, torque that acts opposite to the direction of propeller rotation causes the airplane to roll to
the left. Under these conditions, torque and P-factor cause the airplane to roll and yaw to the left. To counteract this, right rudder and
aileron flight control pressures should be used. During the initial practice of climbs, this may initially seem awkward; however, after
some experience the correction for propeller effects becomes instinctive.
As the airspeed decreases during the climb’s establishment, the airplane’s pitch attitude tends to lower unless the pilot increases the
elevator flight control pressure. Nose-up elevator trim should be used so that the pitch attitude can be maintained without the pilot
holding back elevator pressure. Throughout the climb, since the power should be fixed at the climb power setting, airspeed is
controlled by the use of elevator pressure. The pitch attitude to the natural horizon determines if the pitch attitude is correct and
should be cross-checked to the flight instruments to verify climb performance. [Figure 3-21]
Figure 3-21. Climb indications.