Figure 7-20. Airspeed low and altitude high—lower pitch.
Figure 7-21. Airspeed and altitude high—lower pitch and reduce power.
30.0 29.9 29.8
INCHES MERCURY
ABSOLUTE
MANIFOLD
PRESSURE
Figure 5-20. Airspeed low and altitude high corrected with slighly lowered pitch.
INCHES MERCURY
ABSOLUTE
MANIFOLD
PRESSURE
30.0 29.9 29.8
Figure 5-21. Airspeed and altitude high (lower pitch and reduce power).
low, or vice versa, a change in pitch alone may return the
airplane to the desired altitude and airspeed. [Figure 7-20] If
both airspeed and altitude are high or if both are low, then a
change in both pitch and power is necessary in order to return
to the desired airspeed and altitude. [Figure 7-21]
For changes in airspeed in straight-and-level flight, pitch,
bank, and power must be coordinated in order to maintain
constant altitude and heading. When power is changed to
vary airspeed in straight-and-level flight, a single-engine,
propeller-driven airplane tends to change attitude around all
axes of movement. Therefore, to maintain constant altitude
and heading, apply various control pressures in proportion
to the change in power. When power is added to increase
airspeed, the pitch instruments indicate a climb unless
forward elevator control pressure is applied as the airspeed
changes. With an increase in power, the airplane tends to
yaw and roll to the left unless counteracting aileron and
rudder pressures are applied. Keeping ahead of these changes
requires increasing cross-check speed, which varies with the
type of airplane and its torque characteristics, the extent of
power, and speed change involved.
Power Settings
Power control and airspeed changes are much easier when
approximate power settings necessary to maintain various
airspeeds in straight-and-level flight are known in advance.
However, to change airspeed by any appreciable amount, the
common procedure is to underpower or overpower on initial
power changes to accelerate the rate of airspeed change.
(For small speed changes, or in airplanes that decelerate
or accelerate rapidly, overpowering or underpowering is
not necessary.)
Consider the example of an airplane that requires 23 inches
of mercury ("Hg) of manifold pressure to maintain a normal
cruising airspeed of 120 knots, and 18 "Hg of manifold
pressure to maintain an airspeed of 100 knots. The reduction
in airspeed from 120 knots to 100 knots while maintaining
straight-and-level flight is discussed below and illustrated in
Figures 7-22, 7-23, and 7-24.
Instrument indications, prior to the power reduction, are
shown in Figure 7-22. The basic attitude is established and
maintained on the attitude indicator. The specific pitch,
bank, and power control requirements are detected on these
primary instruments:
Altimeter—Primary Pitch
Heading Indicator—Primary Bank
Airspeed Indicator—Primary Power
Supporting pitch-and-bank instruments are shown in
Figure 7-23. Note that the supporting power instrument is
the manifold pressure gauge (or tachometer if the propeller
is fixed pitch). However, when a smooth power reduction to
approximately 15 "Hg (underpower) is made, the manifold
pressure gauge becomes the primary power instrument.
[Figure 7-23] With practice, power setting can be changed
with only a brief glance at the power instrument, by sensing
30.0 29.9 29.8
Figure 5-22. Straight-and-level flight (normal cruising speed).
Primary pitch
Supporting pitch and bank
Primary power
Supporting bank
Primary bank
Supporting pitch
Supporting power
Figure 7-22. Straight-and-level flight (normal cruising speed).
30.0 29.9 29.8
Figure 5-23. Straight-and-level flight (airspeed decreasing).
Primary pitch
Supporting pitch and bank
Supporting bank
Primary bank
Supporting pitch
Primary power as
airspeed approaches
desired value
Primary power
as throttle is set
Figure 7-23. Straight-and-level flight (airspeed decreasing).
30.0 29.9 29.8
Figure 5-24. Straight-and-level flight (reduced airspeed stabilized).
Supporting power
Primary pitch
Supporting pitch and bank
Supporting bank
Primary bank
Supporting pitch
Primary power
Figure 7-24. Straight-and-level flight (reduced airspeed stabilized).
the movement of the throttle, the change in sound, and the
changes in the feel of control pressures.
As thrust decreases, increase the speed of the cross-check
and be ready to apply left rudder, back-elevator, and aileron
control pressure the instant the pitch-and-bank instruments
show a deviation from altitude and heading. As proficiency
is obtained, a pilot learns to cross-check, interpret, and
control the changes with no deviation of heading and
altitude. Assuming smooth air and ideal control technique
as airspeed decreases, a proportionate increase in airplane
pitch attitude is required to maintain altitude. Similarly,
effective torque control means counteracting yaw with
rudder pressure.
As the power is reduced, the altimeter is primary for
pitch, the heading indicator is primary for bank, and the
manifold pressure gauge is momentarily primary for power
(at 15 "Hg in this example). Control pressures should be
trimmed off as the airplane decelerates. As the airspeed
approaches the desired airspeed of 100 knots, the manifold
pressure is adjusted to approximately 18 "Hg and becomes
the supporting power instrument. The ASI again becomes
primary for power. [Figure 7-24]
Airspeed Changes in Straight-and-Level Flight
Practice of airspeed changes in straight-and-level flight provides
an excellent means of developing increased proficiency in all
three basic instrument skills and brings out some common
errors to be expected during training in straight-and-level flight.
Having learned to control the airplane in a clean configuration
(minimum drag conditions), increase proficiency in cross-
check and control by practicing speed changes while extending
or retracting the flaps and landing gear. While practicing, be
sure to comply with the airspeed limitations specified in the
POH/AFM for gear and flap operation.
Sudden and exaggerated attitude changes may be necessary
in order to maintain straight-and-level flight as the landing
gear is extended and the flaps are lowered in some airplanes.
The nose tends to pitch down with gear extension, and when
flaps are lowered, lift increases momentarily (at partial flap
settings) followed by a marked increase in drag as the flaps
near maximum extension.
Control technique varies according to the lift and drag
characteristics of each airplane. Accordingly, knowledge of
the power settings and trim changes associated with different
combinations of airspeed, gear, and flap configurations
reduces instrument cross-check and interpretation problems.
For example, assume that in straight-and-level flight
instruments indicate 120 knots with power at 23 "Hg/2,300
revolutions per minute (rpm), gear and flaps up. After
reduction in airspeed, with gear and flaps fully extended,
straight-and-level flight at the same altitude requires 25 "Hg
manifold pressure/2,500 rpm. Maximum gear extension
speed is 115 knots; maximum flap extension speed is 105
knots. Airspeed reduction to 95 knots, gear and flaps down,
can be made in the following manner:
1. Maintain rpm at 2,500, since a high power setting is
used in full drag configuration.
2. Reduce manifold pressure to 10 "Hg. As the airspeed
decreases, increase cross-check speed.
3. Make trim adjustments for an increased angle of attack
and decrease in torque.
4. Lower the gear at 115 knots. The nose may tend to
pitch down and the rate of deceleration increases.
Increase pitch attitude to maintain constant altitude,
and trim off some of the back-elevator pressures.
If full flaps are lowered at 105 knots, cross-check,
interpretation, and control must be very rapid. A
simpler technique is to stabilize attitude with gear
down before lowering the flaps.
5. Since 18 "Hg manifold pressure will hold level
flight at 100 knots with the gear down, increase
power smoothly to that setting until the ASI shows
approximately 105 knots. The attitude indicator now
shows approximately two-and-a-half bar width nose-
high in straight-and-level flight.
6. Actuate the flap control and simultaneously increase
power to the predetermined setting (25 "Hg) for the
desired airspeed, and trim off the pressures necessary
to hold constant altitude and heading. The attitude
indicator now shows a bar width nose-low in straight-
and-level flight at 95 knots.
Proficiency in straight-and-level flight is attained when a
pilot can consistently maintain constant altitude and heading
with smooth pitch, bank, power, and trim control during the
pronounced changes in aircraft attitude.
Trim Technique
Proper trim technique is essential for smooth and precise
aircraft control during all phases of flight. By relieving all
control pressures, it is much easier to hold a given attitude
constant and devote more attention to other flight deck duties.
An aircraft is trimmed by applying control pressures to
establish a desired attitude, then adjusting the trim so the
aircraft maintains that attitude when the flight controls are
released. Trim the aircraft for coordinated flight by centering
the ball of the turn-and-slip indicator, by using rudder trim in
the direction the ball is displaced from the center. Differential
power control on multiengine aircraft is an additional factor
affecting coordinated flight. Use balanced power or thrust,
when possible, to aid in maintaining coordinated flight.
Changes in attitude, power, or configuration requires a trim
adjustment in most cases. Using trim alone to establish a
change in aircraft attitude invariably leads to erratic aircraft
control. Smooth and precise attitude changes are best attained
by a combination of control pressures and trim adjustments.
Therefore, when used correctly, trim adjustment is an aid to
smooth aircraft control.
Common Errors in Straight-and-Level Flight
Pitch
Pitch errors usually result from the following faults:
1. Improper adjustment of the attitude indicator’s
miniature aircraft to the wings-level attitude.
Following the initial level off from a climb, check the
attitude indicator and make any necessary adjustment
in the miniature aircraft for level flight indication at
normal cruise airspeed.
2. Insufficient cross-check and interpretation of pitch
instruments. For example, the airspeed indication is
low. The pilot, believing a nose-high attitude exists,
applies forward pressure without noting that a low
power setting is the cause of the airspeed discrepancy.
Increase cross-check speed to include all relevant
instrument indications before making a control input.
3. Uncaging the attitude indicator (if caging feature is
present) when the airplane is not in level flight. The
altimeter and heading indicator must be stabilized with
airspeed indication at normal cruise before pulling
out the caging knob to obtain correct indications in
straight-and-level flight at normal cruise airspeed.
4. Failure to interpret the attitude indicator in terms of
the existing airspeed.
5. Late pitch corrections. Pilots commonly like to leave
well enough alone. When the altimeter indicates a 20
foot error, there is a reluctance to correct it, perhaps
because of fear of overcontrolling. If overcontrolling
is the anticipated error, practice small corrections and
find the cause of overcontrolling. If any deviation is
tolerated, errors increase.
6. Chasing the vertical speed indications. This tendency
can be corrected by proper cross-check of other
pitch instruments, as well as by increasing overall
understanding of instrument characteristics.
7. Using excessive pitch corrections for the altimeter
evaluation. Rushing a pitch correction by making a
large pitch change usually aggravates the existing
error, saving neither time nor effort.
8. Failure to maintain established pitch corrections,
a common error associated with cross-check and
trim errors. For example, having established a
pitch change to correct an altitude error, there is a
tendency to slow down the cross-check, waiting for
the airplane to stabilize in the new pitch attitude. To
maintain the attitude, continue to cross-check and
trim off the pressures.
9. Fixations during cross-check. After initiating a
heading correction, for example, there is a tendency
to become preoccupied with bank control and miss
errors in pitch attitude. Likewise, during an airspeed
change, unnecessary gazing at the power instrument
is common. A small error in power setting is of less
consequence than large altitude and heading errors.
The airplane will not decelerate any faster by staring
at the manifold pressure gauge.
Heading
Heading errors usually result from the following faults:
1. Failure to cross-check the heading indicator, especially
during changes in power or pitch attitude.
2. Misinterpretation of changes in heading, with resulting
corrections in the wrong direction.
3. Failure to note and remember a preselected heading.
4. Failure to observe the rate of heading change and its
relation to bank attitude.
5. Overcontrolling in response to heading changes,
especially during changes in power settings.
6. Anticipating heading changes with premature
application of rudder control.
7. Failure to correct small heading deviations. Unless
zero error in heading is the goal, a pilot will tolerate
larger and larger deviations. Correction of a 1 degree
error takes a lot less time and concentration than
correction of a 20° error.
8. Correcting with improper bank attitude. If correcting a
10° heading error with 20° of bank, the airplane rolls
past the desired heading before the bank is established,
requiring another correction in the opposite direction.
Do not multiply existing errors with errors in
corrective technique.
9. Failure to note the cause of a previous heading error
and thus repeating the same error. For example, the
airplane is out of trim, with a left wing low tendency.
Repeated corrections for a slight left turn are made,
yet trim is ignored.
10. Failure to set the heading indicator properly or failure
to uncage it.
Power
Power errors usually result from the following faults:
1. Failure to know the power settings and pitch attitudes
appropriate to various airspeeds and airplane
configurations.
2. Abrupt use of throttle.
3. Failure to lead the airspeed when making power
changes. For example, during airspeed reduction in
level flight, especially with gear and flaps extended,
adjust the throttle to maintain the slower speed
before the airspeed actually reaches the desired
speed. Otherwise, the airplane decelerates to a speed
lower than that desired, resulting in additional power
adjustments. The amount of lead depends upon how
fast the airplane responds to power changes.
4. Fixation on airspeed or manifold pressure instruments
during airspeed changes, resulting in erratic control
of both airspeed and power.
Trim
Trim errors usually result from the following faults:
1. Improper adjustment of seat or rudder pedals for
comfortable position of legs and feet. Tension in the
ankles makes it difficult to relax rudder pressures.
2. Confusion about the operation of trim devices that
differ among various airplane types. Some trim wheels
are aligned appropriately with the airplane’s axes;
others are not. Some rotate in a direction contrary to
what is expected.
3. Faulty sequence in trim technique. Trim should be
used not as a substitute for control with the wheel
(stick) and rudders, but to relieve pressures already
held to stabilize attitude. As proficiency is gained, little
conscious effort is required to trim off the pressures
as they occur.
4. Excessive trim control. This induces control pressures
that must be held until the airplane is trimmed
properly. Use trim frequently and in small amounts.
5. Failure to understand the cause of trim changes. Lack
of understanding the basic aerodynamics related to
basic instrument skills causes a pilot to continually
lag behind the airplane.
30.0 29.9 29.8
Figure 5-25. Climb entry for constant-airspeed climb.
Supporting pitch and bank
Supporting bank
Primary bank
Supporting pitch
Primary power
Figure 7-25. Climb entry for constant airspeed climb.
Straight Climbs and Descents
Climbs
For a given power setting and load condition, there is only
one attitude that gives the most efficient rate of climb. The
airspeed and climb power setting that determines this climb
attitude are given in the performance data found in the POH/
AFM. Details of the technique for entering a climb vary
according to airspeed on entry and the type of climb (constant
airspeed or constant rate) desired. (Heading and trim control
are maintained as discussed in straight-and-level flight.)
Entry
To enter a constant-airspeed climb from cruising airspeed,
raise the miniature aircraft to the approximate nose-high
indication for the predetermined climb speed. The attitude
varies according to the type of airplane. Apply light back-
elevator pressure to initiate and maintain the climb attitude.
The pressures vary as the airplane decelerates. Power may
be advanced to the climb power setting simultaneously with
the pitch change or after the pitch change is established and
the airspeed approaches climb speed. If the transition from
level flight to climb is smooth, the VSI shows an immediate
trend upward, continues to move slowly, and then stops at
a rate appropriate to the stabilized airspeed and attitude.
(Primary and supporting instruments for the climb entry are
shown in Figure 7-25.)
Once the airplane stabilizes at a constant airspeed and attitude,
the ASI is primary for pitch and the heading indicator remains
primary for bank. [Figure 7-26] Monitor the tachometer or
manifold pressure gauge as the primary power instrument to
ensure the proper climb power setting is being maintained.
If the climb attitude is correct for the power setting selected,
the airspeed will stabilize at the desired speed. If the airspeed
is low or high, make an appropriately small pitch correction.
To enter a constant airspeed climb, first complete the airspeed
reduction from cruise airspeed to climb speed in straight-
and-level flight. The climb entry is then identical to entry
from cruising airspeed, except that power must be increased
simultaneously to the climb setting as the pitch attitude is
increased. Climb entries on partial panel are more easily
and accurately controlled if entering the maneuver from
climbing speed.
The technique for entering a constant-rate climb is very
similar to that used for entry to a constant-airspeed climb
from climb airspeed. As the power is increased to the
approximate setting for the desired rate, simultaneously
raise the miniature aircraft to the climbing attitude for the
desired airspeed and rate of climb. As the power is increased,
the ASI is primary for pitch control until the vertical speed
approaches the desired value. As the vertical speed needle
stabilizes, it becomes primary for pitch control and the ASI
becomes primary for power control. [Figure 7-27]
30.0 29.9 29.8
Figure 5-26. Stabilized climb at constant airspeed.
Supporting pitch and bank
Primary pitch
Supporting bank
Primary bank
Supporting pitch
Figure 7-26. Stabilized climb at constant airspeed.
30.0 29.9 29.8
Figure 5-27. Stabilized climb at constant rate.
Supporting pitch and bank
Primary power
Supporting bank
Primary bank
Primary pitch
Figure 7-27. Stabilized climb at constant rate.
30.0 29.9 29.8
Figure 5-28. Airspeed low and vertical speed high-reduce pitch.
Supporting pitch and bank
Primary power
Supporting bank
Primary bank
Primary pitch
Figure 7-28. Airspeed low and vertical speed high—reduce pitch.
Pitch and power corrections must be promptly and closely
coordinated. For example, if the vertical speed is correct, but
the airspeed is low, add power. As the power is increased,
the miniature aircraft must be lowered slightly to maintain
constant vertical speed. If the vertical speed is high and the
airspeed is low, lower the miniature aircraft slightly and note
the increase in airspeed to determine whether or not a power
change is also necessary. [Figure 7-28] Familiarity with the
approximate power settings helps to keep pitch and power
corrections at a minimum.
Leveling Off
To level off from a climb and maintain an altitude, it is
necessary to start the level off before reaching the desired
altitude. The amount of lead varies with rate of climb and
pilot technique. If the airplane is climbing at 1,000 fpm, it
continues to climb at a decreasing rate throughout the transition
to level flight. An effective practice is to lead the altitude by
10 percent of the vertical speed shown (500 fpm/ 50-foot lead,
1,000 fpm/100-foot lead).
To level off at cruising airspeed, apply smooth, steady
forward-elevator pressure toward level flight attitude for
the speed desired. As the attitude indicator shows the pitch
change, the vertical speed needle moves slowly toward zero,
the altimeter needle moves more slowly, and the airspeed
shows acceleration. [Figure 7-29] When the altimeter, attitude
indicator, and VSI show level flight, constant changes in pitch
and torque control have to be made as the airspeed increases.
As the airspeed approaches cruising speed, reduce power to
the cruise setting. The amount of lead depends upon the rate
of acceleration of the airplane.
To level off at climbing airspeed, lower the nose to the
pitch attitude appropriate to that airspeed in level flight.
Power is simultaneously reduced to the setting for that
airspeed as the pitch attitude is lowered. If power reduction
is at a rate proportionate to the pitch change, airspeed will
remain constant.
Descents
A descent can be made at a variety of airspeeds and attitudes
by reducing power, adding drag, and lowering the nose to
a predetermined attitude. The airspeed eventually stabilizes
at a constant value. Meanwhile, the only flight instrument
providing a positive attitude reference is the attitude indicator.
Without the attitude indicator (such as during a partial panel
descent), the ASI, altimeter, and VSI show varying rates of
change until the airplane decelerates to a constant airspeed at
a constant attitude. During the transition, changes in control
pressure and trim, as well as cross-check and interpretation,
must be accurate to maintain positive control.