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Steep turns consist
of single to multiple 360° to 720° turns,
in either or both directions, using a bank angle
between 45° to 60°. The objective of
the steep turn is to develop a pilot’s
skill in flight control smoothness and coordination,
an awareness of the airplane’s orientation
to outside references, division of attention
between flight control application, and the
constant need to scan for hazards.
When steep turns are first demonstrated, the
pilot will be in an unfamiliar environment when
compared to what was previously experienced
in shallow bank angled turns; however, the fundamental
concepts of turns remain the same in the execution
of steep turns. When performing steep turns,
pilots will be exposed to higher load factors,
the airplane’s inherent overbanking tendency,
the loss of vertical component of lift when
the wings are steeply banked, the need for substantial
pitch control pressures, and the need for additional
power to maintain altitude and airspeed during
the turn.
As discussed in previous chapters, when an airplane
is banked, the total lift is comprised of a
vertical component of lift and a horizontal
component of lift. In order to not lose altitude,
the pilot must increase the wing’s angle
of attack (AOA) to ensure that the vertical
component of lift is sufficient to maintain
altitude. In a steep turn, the pilot will need
to increase pitch with elevator back pressures
that are greater than what has been previously
utilized. Total lift must increase substantially
to balance the load factor or G-force (G). The
load factor is the vector resultant of gravity
and centrifugal force. For example, in a level
altitude, 45° banked turn, the resulting
load factor is 1.4; in a level altitude, 60°
banked turn, the resulting load factor is 2.0.
To put this in perspective, with a load factor
of 2.0, the effective weight of the aircraft
will double. Pilots should realize load factors
increase dramatically beyond 60°. Most general
aviation airplanes are designed for a load limit
of 3.8Gs. Regardless of the airspeed or what
airplane is involved, for a given bank angle
in a level altitude turn, the same load factor
will always be produced. A light, general aviation
airplane in a level altitude, 45° angle
of bank turn will experience a load factor of
1.4 just as a large commercial airliner will
in the same level altitude, 45° angle of
bank turn.
Because of the higher load factors, steep turns
should be performed at an airspeed that does
not exceed the airplane’s design maneuvering
speed (VA) or the manufacturer’s recommended
speed. Maximum turning performance is accomplished
when an airplane has both a fast rate of turn
and minimum radius of turn, which is effected
by both airspeed and angle of bank. Each airplane’s
turning performance is limited by structural
and aerodynamic design, as well as available
power. The airplane’s limiting load factor
determines the maximum bank angle that can be
maintained in level flight without exceeding
the airplane’s structural limitations or
stalling. As the load factor increases, so does
the stalling speed. For example, if an airplane
stalls in level flight at 50 knots, it will
stall at 60 knots in a level altitude, 45°
banked turn and at 70 knots in a level altitude,
60° banked turn. Stalling speed increases
at the square root of the load factor. As the
bank angle increases in level flight, the margin
between stalling speed and maneuvering speed
decreases—an important concept for a pilot
to remain cognizant.
In addition to the increased load factors, the
airplane will exhibit what is called “overbanking
tendency.” Recall from a previous chapter
on the discussion of overbanking tendency. In
most flight maneuvers, bank angles are shallow
enough that the airplane exhibits positive or
neutral stability about the longitudinal axis;
however, as bank angles steepen, the airplane
will exhibit the behavior to continue rolling
in the direction of the bank unless deliberate
and opposite aileron pressure is held against
the bank. Also, pilots should be mindful of
the various left turning tendencies, such as
P-factor, which requires effective rudder aileron
coordination.
Before starting any practice maneuver, the pilot
must ensure that the area is clear of air traffic
and other hazards. Further, distant references
such as a mountain peak or road should be chosen
to allow the pilot to assess when to begin rollout
from the turn. After establishing the manufacturer’s
recommended entry speed or the design maneuvering
speed, the airplane should be smoothly rolled
into the desired bank angle somewhere between
45° to 60°. As the bank angle is being
established, generally prior to 30° of bank,
elevator back pressure should be smoothly applied
to increase the AOA. After the selected bank
angle has been reached, the pilot will find
that considerable force is required on the elevator
control to hold the airplane in level flight—to
maintain altitude. Pilots should keep in mind
that as the AOA increases, so does drag. Consequently,
power must be added to maintain altitude and
airspeed.
Steep turns can be conducted more easily by
the use of elevator trim and power as the maneuver
is entered. In many light general aviation airplanes,
as the bank angle transitions from medium to
steep, increasing elevator up trim and adding
a small increase in engine power minimizes control
pressure requirements. Pilots must not forget
to remove both the trim and power inputs as
the maneuver is completed.
To maintain bank angle, altitude, as well as
orientation, requires an awareness of the relative
position of the horizon to the nose and the
wings. The pilot who references the aircraft’s
attitude by observing only the nose will have
difficulty maintaining altitude. A pilot who
observes both the nose and the wings relative
to the horizon is likely able to maintain altitude
within performance standards. Altitude deviations
are primary errors exhibited in the execution
of steep turns. If the altitude does increase
or decrease, changing elevator back pressure
could be used to alter the altitude; however,
a more effective method is a slight increase
or decrease in bank angle to control small altitude
deviations. If altitude is decreasing, reducing
the bank angle a few degrees helps recover or
stop the altitude loss trend; also, if altitude
is increasing, increasing the bank angle a few
degrees helps recover or stop the altitude increase
trend—all bank angle changes should be
accomplished with coordinated use of aileron
and rudder.
The rollout from the steep turn should be timed
so that the wings reach level flight when the
airplane is on heading from which the maneuver
was started. A good rule of thumb is to begin
the rollout at ½ the number of degrees
of bank prior to reaching the terminating heading.
For example, if a right steep turn was begun
on a heading of 270° and if the bank angle
is 60°, the pilot should begin the rollout
30° prior or at a heading of 240°. While
the rollout is being made, elevator back pressure,
trim, and power should be gradually reduced,
as necessary, to maintain the altitude and airspeed.
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