Introduction
Instrument flying techniques differ according to aircraft
type, class, performance capability, and instrumentation.
Therefore, the procedures and techniques that follow need
to be modified to suit individual aircraft. Recommended
procedures, performance data, operating limitations, and
flight characteristics of a particular aircraft are available in the
Pilot’s Operating Handbook/Airplane Flight Manual (POH/
AFM) for study before practicing the flight maneuvers.
The flight maneuvers discussed in Chapter 7-I assume the
use of a single-engine, propeller-driven small airplane with
retractable gear and flaps and a panel with instruments
representative of those discussed earlier in Chapter 5, Flight
Instruments. With the exception of the instrument takeoff, all
of the maneuvers can be performed on “partial panel,” with
the attitude gyro and heading indicator covered or inoperative.
Airplane Basic
Flight Maneuvers
Chapter 7, Section I
Using Analog Instrumentation
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Figure 5-2. Pitch attitude and airspeed in level fiight, fast cruise speed.
Figure 7-2. Pitch attitude and airspeed in level flight, fast
cruise speed.
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Figure 5-1. Pitch attitude and airspeed in level fiight, slow cruise speed.
Figure 7-1. Pitch attitude and airspeed in level flight, slow
cruise speed.
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Figure 5-3. Pitch attitude and airspeed in level fiight, normal cruise speed.
Figure 7-3. Pitch attitude and airspeed in level flight, normal
cruise speed.
Straight-and-Level Flight
Pitch Control
The pitch attitude of an airplane is the angle between the
longitudinal axis of the airplane and the actual horizon. In
level flight, the pitch attitude varies with airspeed and load.
For training purposes, the latter factor can normally be
disregarded in small airplanes. At a constant airspeed, there is
only one specific pitch attitude for level flight. At slow cruise
speeds, the level flight attitude is nose high with indications
as in Figure 7-1; at fast cruise speeds, the level-flight attitude
is nose low. [Figure 7-2] Figure 7-3 shows the indications
for the attitude at normal cruise speeds. The instruments used
to determine the pitch attitude of the aircraft are the attitude
indicator, the altimeter, the vertical speed indicator (VSI),
and the airspeed indicator (ASI).
Attitude Indicator
The attitude indicator gives the direct indication of pitch
attitude. The desired pitch attitude is gained by using the
elevator control to raise or lower the miniature aircraft in
relation to the horizon bar. This corresponds to the way pitch
attitude is adjusted in visual flight by raising or lowering
the nose of the airplane in relation to the natural horizon.
However, unless the airspeed is constant, and until the
level flight attitude for that airspeed has been identified and
established, there is no way to know whether level flight as
Figure 7-4. Pitch correction for level flight, one-half bar width.
Figure 7-5. Pitch correction for level flight, one bar width.
Figure 7-6. Pitch correction for level flight, one-and-one-half
bar width.
Figure 5-4. Pitch correction for level flight, half-bar width
Figure 5-5. Pitch correction for level flight, two-bar width
Figure 5-6. Pitch correction for level flight, three-bar width
indicated on the attitude indicator is resulting in level flight
as shown on the altimeter, VSI, and ASI. If the miniature
aircraft of the attitude indicator is properly adjusted on the
ground before takeoff, it shows approximately level flight at
normal cruise speed when the pilot completes the level off
from a climb. If further adjustment of the miniature aircraft
is necessary, the other pitch instruments must be used to
maintain level flight while the adjustment is made.
To practice pitch control for level flight using only the
attitude indicator, use the following exercise. Restrict the
displacement of the horizon bar to a one-half bar width, a
bar width up or down, then a one-and-one-half bar width.
One-half, one, and one-and-one-half bar width nose-high
attitudes are shown in Figures 7-4, 7-5, and 7-6.
An instructor pilot can demonstrate these normal pitch
corrections and compare the indications on the attitude
indicator with the airplane’s position to the natural horizon.
Pitch attitude changes for corrections to level flight by
reference to instruments are much smaller than those
commonly used for visual flight. With the airplane correctly
trimmed for level flight, the elevator displacement and the
control pressures necessary to effect these standard pitch
changes are usually very slight. The following are a few
helpful hints to help determine how much elevator control
pressure is required.
First, a tight grip on the controls makes it difficult to feel
control pressure changes. Relaxing and learning to control
the aircraft usually takes considerable conscious effort during
the early stages of instrument training.
Second, make smooth and small pitch changes with positive
pressure. With practice, a pilot can make these small pitch
corrections up or down, “freezing” (holding constant) the
one-half, full, and one-and-one-half bar widths on the
attitude indicator.
Third, with the airplane properly trimmed for level flight,
momentarily release all pressure on the elevator control
when becoming aware of tenseness. This is a reminder that
the airplane is stable; except under turbulent conditions, it
maintains level flight if left alone. Even when no control
change is called for, it is difficult to resist the impulse to
move the controls. This may be one of the most difficult
initial training problems in instrument flight.
Altimeter
At constant power, any deviation from level flight (except
in turbulent air) is the result of a pitch change. Therefore,
the altimeter gives an indirect indication of the pitch attitude
in level flight, assuming constant power. Since the altitude
Figure 7-7. Using the altimeter for pitch interpretation, a high
altitude means a nose-high pitch attitude.
Figure 7-8. Pitch correction following altitude increase—lower
nose to correct altitude error.
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Figure 5-7. Using the altimeter for pitch interpretation, a high altitude means a
nose-high pitch attitude.
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Figure 5-8. Pitch correction following altitude increase-lower nose to correct
attitude error.
should remain constant when the airplane is in level flight,
any deviation from the desired altitude signals the need for a
pitch change. If the aircraft is gaining altitude, the nose must
be lowered. [Figures 7-7 and 7-8]
The rate of movement of the altimeter needle is as important
as its direction of movement in maintaining level flight
without the use of the attitude indicator. An excessive pitch
deviation from level flight results in a relatively rapid change
of altitude; a slight pitch deviation causes a slow change.
Thus, if the altimeter needle moves rapidly clockwise, assume
a considerable nose-high deviation from level flight attitude.
Conversely, if the needle moves slowly counterclockwise to
indicate a slightly nose-low attitude, assume that the pitch
correction necessary to regain the desired altitude is small.
As the altimeter is added to the attitude indicator in a cross-
check, a pilot learns to recognize the rate of movement of
the altimeter needle for a given pitch change as shown on
the attitude indicator.
To practice precision control of pitch in an airplane without
an attitude indicator, make small pitch changes by visual
reference to the natural horizon and note the rate of movement
of the altimeter. Note what amount of pitch change gives
the slowest steady rate of change on the altimeter. Then
practice small pitch corrections by accurately interpreting
and controlling the rate of needle movement.
An instructor pilot can demonstrate an excessive nose-down
deviation (indicated by rapid movement of the altimeter
needle) and then, as an example, show the result of improper
corrective technique. The normal impulse is to make a
large pitch correction in a hurry, but this inevitably leads
to overcontrolling. The needle slows down, then reverses
direction, and finally indicates an excessive nose-high
deviation. The result is tension on the controls, erratic control
response, and increasingly extreme control movements. The
correct technique, which is slower and smoother, returns the
airplane to the desired attitude more quickly, with positive
control and no confusion.
When a pitch error is detected, corrective action should be
taken promptly, but with light control pressures and two
distinct changes of attitude: (1) a change of attitude to stop
the needle movement and (2) a change of attitude to return
to the desired altitude.
When the altimeter indicates an altitude deviation, apply
just enough elevator pressure to decrease the rate of needle
movement. If it slows down abruptly, ease off some of the
pressure until the needle continues to move, but ease off
slowly. Slow needle movement means the airplane attitude
is close to level flight. Add slightly more corrective pressure
to stop the direction of needle movement. At this point, level
flight is achieved; a reversal of needle movement means
the aircraft has passed through it. Relax control pressures
carefully, continuing to cross-check since changing airspeed
causes changes in the effectiveness of a given control
pressure. Next, adjust the pitch attitude with elevator pressure
for the rate of change of altimeter needle movement that is
correlated with normal pitch corrections and return to the
desired altitude.
As a rule of thumb, for errors of less than 100 feet, use a half
bar width correction. [Figures 7-9 and 7-10] For errors in
excess of 100 feet, use an initial full bar width correction.
[Figures 7-11 and 7-12] Practice predetermined altitude
changes using the altimeter alone, then in combination with
the attitude indicator.
Vertical Speed Indicator (VSI)
The VSI, like the altimeter, gives an indirect indication of
pitch attitude and is both a trend and a rate instrument. As
a trend instrument, it shows immediately the initial vertical
movement of the airplane, which disregarding turbulence
can be considered a reflection of pitch change. To maintain
level flight, use the VSI in conjunction with the altimeter and
attitude indicator. Note any positive or negative trend of the
needle from zero and apply a very light corrective elevator
Figure 7-9. Altitude error, less than 100 feet.
Figure 7-10. Pitch correction, less than 100 feet—one-half bar low
to correct altitude error.
Figure 7-11. Altitude error, greater than 100 feet.
Figure 7-12. Pitch correction, greater than 100 feet—one bar
correction initially.
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Figure 5-9. Altitude error, less than 100 feet.
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Figure 5-10. Pitch correction, less than 100 feet- 1/2 bar low to correct altitude error.
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Figure 5-11. Altitude error, greater than 100 feet.
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Figure 5-12. Pitch correction, freater than 100 feet-1 bar correction initially.
pressure. As the needle returns to zero, relax the corrective
pressure. If control pressures have been smooth and light, the
needle reacts immediately and slowly, and the altimeter shows
little or no change of altitude. As a rate instrument, the VSI
requires consideration of lag characteristics.
Lag refers to the delay involved before the needle attains a
stable indication following a pitch change. Lag is directly
proportional to the speed and magnitude of a pitch change.
If a slow, smooth pitch change is initiated, the needle moves
with minimum lag to a point of deflection corresponding
to the extent of the pitch change, and then stabilizes as the
aerodynamic forces are balanced in the climb or descent.
A large and abrupt pitch change produces erratic needle
movement, a reverse indication, and introduces greater time
delay (lag) before the needle stabilizes. Pilots are cautioned
not to chase the needle when flight through turbulent
conditions produces erratic needle movements. The apparent
lag in airspeed indications with pitch changes varies greatly
among different airplanes and is due to the time required for
the airplane to accelerate or decelerate when the pitch attitude
is changed. There is no appreciable lag due to the construction
or operation of the instrument. Small pitch changes, smoothly
executed, result in an immediate change of airspeed.
When using the VSI as a rate instrument and combining it
with the altimeter and attitude indicator to maintain level
flight, a pilot should know that the amount the altimeter
needle moves from the desired altitude governs the rate that
should be used to return to that altitude. A rule of thumb is to
make an attitude change that results in a vertical-speed rate
approximately double the error in altitude. For example, if
altitude is off by 100 feet, the rate of return to the desired
altitude should be approximately 200 feet per minute (fpm).
If it is off by more than 100 feet, the correction should
be correspondingly greater, but should never exceed the
optimum rate of climb or descent for the airplane at a given
airspeed and configuration.
A deviation of more than 200 fpm from the desired rate
of return is considered overcontrolling. For example, if
attempting to change altitude by 200 feet, a rate in excess of
400 fpm indicates overcontrolling.
When returning to an altitude, the VSI is the primary pitch
instrument. Occasionally, the VSI is slightly out of calibration
and may indicate a climb or descent when the airplane is in
level flight. If the instrument cannot be adjusted, take the
error into consideration when using it for pitch control. For
Figure 7-13. Constant power plus constant pitch equals constant
speed.
Figure 7-14. Constant power plus decreased pitch equals increased
airspeed.
Figure 7-15. Constant power plus increased pitch equals decreased
airspeed.
Constant Airspeed Constant Pitch
Increased Airspeed Decreased Pitch
Decreased Airspeed Increased Pitch
Figure 5-13. Constant power plus constant pitch equals constant airspeed.
Figure 5-14. Constant power plus decreased pitch equals increased airspeed..
Figure 5-15. Constant power plus increased pitch equals decreased airspeed.
example, if the needle indicates a descent of 200 fpm while
in level flight, use this indication as the zero position.
Airspeed Indicator (ASI)
The ASI presents an indirect indication of the pitch attitude.
In non-turbulent conditions with a constant power setting and
pitch attitude, airspeed remains constant. [Figure 7-13] As the
pitch attitude lowers, airspeed increases, and the nose should
be raised. [Figure 7-14] As the pitch attitude rises, airspeed
decreases, and the nose should be lowered. [Figure 7-15] A
rapid change in airspeed indicates a large pitch change, and
a slow change of airspeed indicates a small pitch change.
Pitch control in level flight is a question of cross-check and
interpretation of the instrument panel for the instrument
information that enables a pilot to visualize and control
pitch attitude. Regardless of individual differences in
cross-check technique, all pilots should use the instruments
that give the best information for controlling the airplane
in any given maneuver. Pilots should also check the other
instruments to aid in maintaining the primary instruments
at the desired indication.
As noted previously, the primary instrument is the one
that gives the most pertinent information for a particular
maneuver. It is usually the one that should be held at a
constant indication. Which instrument is primary for pitch
control in level flight, for example? This question should
be considered in the context of specific airplane, weather
conditions, pilot experience, operational conditions, and
other factors. Attitude changes must be detected and
interpreted instantly for immediate control action in high-
performance airplanes. On the other hand, a reasonably
proficient instrument pilot in a slower airplane may rely
more on the altimeter for primary pitch information,
especially if it is determined that too much reliance on the
attitude indicator fails to provide the necessary precise
attitude information. Whether the pilot decides to regard
the altimeter or the attitude indicator as primary depends
on which approach will best help control the attitude. In
this handbook, the altimeter is normally considered as the
primary pitch instrument during level flight.
Bank Control
The bank attitude of an airplane is the angle between the
airplane’s wings and the natural horizon. To maintain a
straight-and-level flightpath, the wings of the airplane are
kept level with the horizon (assuming the airplane is in
coordinated flight). The instruments used for bank control
are the attitude indicator, the heading indicator, and the
turn coordinator. Figure 7-16 illustrates coordinated flight.
The aircraft is banked left with the attitude indicator and
turn coordinator indicating the bank. The heading indicator
indicates a left turn by apparent clockwise rotation of the
compass card behind the airplane silhouette.
Attitude Indicator
The attitude indicator shows any change in bank attitude
directly and instantly and is, therefore, a direct indicator. On
the standard attitude indicator, the angle of bank is shown
pictorially by the relationship of the miniature aircraft to the
artificial horizon bar and by the alignment of the pointer with
the banking scale at the top of the instrument. On the face of
the standard three-inch instrument, small angles of bank can
be difficult to detect by reference to the miniature aircraft,
especially if leaning to one side or changing a seating position
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Bank control
Figure 5-16. Instruments used for bank control.
Figure 7-16. Instruments used for bank control.
Figure 7-17. Bank interpretation with the attitude indicator.
0°
30°
45°
60°
90°
slightly. The position of the scale pointer is a good check
against the apparent miniature aircraft position. Disregarding
precession error, small deviations from straight coordinated
flight can be readily detected on the scale pointer. The
banking index may be graduated as shown in Figure 7-17,
or it may be graduated in 30° increments.
The instrument depicted in Figure 7-17 has a scale pointer
that moves in the same direction of bank shown by the
miniature aircraft. In this case, the aircraft is in a left 15°
bank. Precession errors in this instrument are common
and predictable, but the obvious advantage of the attitude
indicator is an immediate indication of both pitch attitude
and bank attitude in a single glance. Even with the precession
errors associated with many attitude indicators, the quick
attitude presentation requires less visual effort and time for
positive control than other flight instruments.
Heading Indicator
The bank attitude of an aircraft in coordinated flight is shown
indirectly on the heading indicator, since banking results in
a turn and change in heading. Assuming the same airspeed
in both instances, a rapid movement of the heading indicator
(azimuth card in a directional gyro) indicates a large angle
of bank, whereas slow movement reflects a small angle of
bank. Note the rate of movement of the heading indicator
and compare it to the attitude indicator’s degrees of bank.
The attitude indicator’s precession error makes a precise
check of heading information necessary in order to maintain
straight flight.
When deviations from straight flight are noted on the heading
indicator, correct to the desired heading using a bank angle no
greater than the number of degrees to be turned. In any case,
limit bank corrections to a bank angle no greater than that
required for a standard rate turn. Use of larger bank angles
requires a very high level of proficiency, and normally results
in overcontrolling and erratic bank control.
Turn Coordinator
The miniature aircraft of the turn coordinator gives an
indirect indication of the bank attitude of the airplane.
When the miniature aircraft is level, the airplane is in
straight flight. When the miniature airplane is aligned with
one of the alignment marks and the aircraft is rolling to the
left or right the indication represents the roll rate, with the
alignment marks indicating a roll of 3 degrees per second
in the direction of the miniature aircraft. This can be seen
in level flight when a bank is introduced either to the left
or the right. The turn coordinator’s indicator will indicate
the rolling motion although there is no turn being made.
Conversely, a pedal input to the right or left causes the aircraft
to turn momentarily about its vertical axis (with no rolling
motion) with an indication of turn on the turn coordinator.
After the turn becomes stabilized and the aircraft is no
longer rolling, the turn coordinator displays the rate of turn
with the alignment marks equaling a turn of 3 degrees per
second. The turn coordinator is able to display both roll and
turn parameters because its electrically-powered gyroscope
is canted at an angle. As a result, the turn-and-slip indicator
provides both roll and turn indications. Autopilots in general
aviation today use this instrument in determining both roll
and turn information. After the completion of a turn, return
to straight flight is accomplished by coordinated aileron and
Figure 7-18. Skid indication.
Figure 7-19. Slip indication.
OFF
2 MIN TURN
DC ELEC
L R
Figure 5-18. Slip indication.
OFF
2 MIN TURN
DC ELEC
L R
Figure 5-19. Skid indication.
rudder pressure to level the miniature aircraft. Include the
miniature aircraft in the cross-check and correct for even
the smallest deviations from the desired position. When
this instrument is used to maintain straight flight, control
pressures must be applied very lightly and smoothly.
The ball of the turn coordinator is actually a separate
instrument, conveniently located under the miniature
aircraft because the two instruments are used together.
The ball instrument indicates the quality of the turn. If the
ball is off-center, the airplane is slipping or skidding. That
is, if the coordinator’s miniature airplane is tilted left and
the ball is displaced to the right, the aircraft is in a skid.
[Figure 7-18] If however, the miniature airplane is tilted to
the right with the ball off-center to the right, the aircraft is in
a slip. [Figure 7-19] If the wings are level and the airplane
is properly trimmed, the ball remains in the center, and the
airplane is in straight flight. If the ball is not centered, the
airplane is improperly trimmed.
To maintain straight-and-level flight with proper trim, note
the direction of ball displacement. If the ball is to the left of
center and the left wing is low, apply left rudder pressure
to center the ball and correct the slip. At the same time,
apply right aileron pressure as necessary to level the wings,
cross-checking the heading indicator and attitude indicator
while centering the ball. If the wings are level and the ball is
displaced from the center, the airplane is skidding. Note the
direction of ball displacement and use the same corrective
technique as for an indicated slip. Center the ball (left ball/
left rudder, right ball/right rudder), use aileron as necessary
for bank control and retrim.
To trim the airplane using only the turn coordinator, use
aileron pressure to level the miniature aircraft and rudder
pressure to center the ball. Hold these indications with control
pressures, gradually releasing them while applying rudder
trim sufficient to relieve all rudder pressure. Apply aileron
trim, if available, to relieve aileron pressure. With a full
instrument panel, maintain a wings-level attitude by reference
to all available instruments while trimming the airplane.
Turn-and-Slip Indicator (Needle and Ball)
Unlike the turn coordinator that provides three indications
(roll, turn, and trim), the turn-and-slip indicator provides
two: turn-rate and trim. Although the turn-and-slip indicator
needle provides an indication of turn only, it provides an
indirect indication of aircraft attitude when used with roll
indicators, such as a heading indicator or magnetic compass.
As with the turn coordinator (after stabilizing from a roll),
when the turn-and-slip indicator’s needle is aligned with the
alignment marks, the aircraft is in a standard turn of 3 degrees
per second or 360° in 2 minutes.
The ball of the turn-and-bank indicator provides important
trim in the same manner that the ball in the turn coordinator
does. Figures 7-18 and 7-19 provide a comparison of the
two instruments.
Power Control
Power produces thrust which, with the appropriate angle of
attack of the wing, overcomes the forces of gravity, drag,
and inertia to determine airplane performance.
Power control must be related to its effect on altitude and
airspeed, since any change in power setting results in a change
in the airspeed or the altitude of the airplane. At any given
airspeed, the power setting determines whether the airplane
is in level flight, in a climb, or in a descent. If the power is
increased in straight-and-level flight and the airspeed held
constant, the airplane climbs. If power is decreased while
the airspeed is held constant, the airplane descends. On the
other hand, if altitude is held constant, the power applied
determines the airspeed.
The relationship between altitude and airspeed determines the
need for a change in pitch or power. If the airspeed is not the
desired value, always check the altimeter before deciding that
a power change is necessary. Think of altitude and airspeed
as interchangeable; altitude can be traded for airspeed by
lowering the nose or convert airspeed to altitude by raising
the nose. If altitude is higher than desired and airspeed is