Introduction
Attitude instrument flying is defined as the control of an
aircraft’s spatial position by using instruments rather than
outside visual references. Today’s aircraft come equipped
with analog and/or digital instruments. Analog instrument
systems are mechanical and operate with numbers
representing directly measurable quantities, such as a watch
with a sweep second hand. In contrast, digital instrument
systems are electronic and operate with numbers expressed
in digits. Although more manufacturers are providing aircraft
with digital instrumentation, analog instruments remain more
prevalent. This section acquaints the pilot with the use of
analog flight instruments.
Airplane Attitude
Instrument Flying
Chapter 6, Section I
Using Analog Instrumentation
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T urning
Figure 6-1. Control instruments.
Any flight, regardless of the aircraft used or route flown,
consists of basic maneuvers. In visual flight, aircraft attitude
is controlled by using certain reference points on the
aircraft with relation to the natural horizon. In instrument
flight, the aircraft attitude is controlled by reference to
the flight instruments. Proper interpretation of the flight
instruments provides essentially the same information that
outside references do in visual flight. Once the role of each
instrument in establishing and maintaining a desired aircraft
attitude is learned, a pilot is better equipped to control the
aircraft in emergency situations involving failure of one or
more key instruments.
Learning Methods
The two basic methods used for learning attitude instrument
flying are “control and performance” and “primary and
supporting.” Both methods utilize the same instruments and
responses for attitude control. They differ in their reliance on
the attitude indicator and interpretation of other instruments.
Attitude Instrument Flying Using the Control and
Performance Method
Aircraft performance is achieved by controlling the aircraft
attitude and power. Aircraft attitude is the relationship
of both the aircraft’s pitch and roll axes in relation to the
Earth’s horizon. An aircraft is flown in instrument flight by
controlling the attitude and power, as necessary, to produce
both controlled and stabilized flight without reference to a
visible horizon. This overall process is known as the control
and performance method of attitude instrument flying.
Starting with basic instrument maneuvers, this process can
be applied through the use of control, performance, and
navigation instruments resulting in a smooth flight from
takeoff to landing.
Control Instruments
The control instruments display immediate attitude and power
indications and are calibrated to permit those respective
adjustments in precise increments. In this discussion, the
term “power” is used in place of the more technically correct
term “thrust or drag relationship.” Control is determined
by reference to the attitude and power indicators. Power
indicators vary with aircraft and may include manifold
pressure, tachometers, fuel flow, etc. [Figure 6-1]
Performance Instruments
The performance instruments indicate the aircraft’s actual
performance. Performance is determined by reference to
the altimeter, airspeed, or vertical speed indicator (VSI).
[Figure 6-2]
Navigation Instruments
The navigation instruments indicate the position of the aircraft
in relation to a selected navigation facility or fix. This group
of instruments includes various types of course indicators,
range indicators, glideslope indicators, and bearing pointers.
[Figure 6-3] Newer aircraft with more technologically
advanced instrumentation provide blended information,
giving the pilot more accurate positional information.
Procedural Steps in Using Control and
Performance
1. Establish an attitude and power setting on the
control instruments that results in the desired
performance. Known or computed attitude changes
and approximated power settings helps to reduce the
pilot’s workload.
2. Trim (fine tune the control forces) until control
pressures are neutralized. Trimming for hands-off
flight is essential for smooth, precise aircraft control.
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Figure 6-2. Performance instruments.
Figure 6-3. Navigation instruments.
It allows a pilot to attend to other flight deck duties
with minimum deviation from the desired attitude.
3. Cross-check the performance instruments to determine
if the established attitude or power setting is providing
the desired performance. The cross-check involves
both seeing and interpreting. If a deviation is noted,
determine the magnitude and direction of adjustment
required to achieve the desired performance.
4. Adjust the attitude and/or power setting on the control
instruments as necessary.
Aircraft Control During Instrument Flight
Attitude Control
Proper control of aircraft attitude is the result of proper use
of the attitude indicator, knowledge of when to change the
Figure 6-4. Pitch instruments.
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attitude, and then smoothly changing the attitude a precise
amount. The attitude reference provides an immediate, direct,
and corresponding indication of any change in aircraft pitch
or bank attitude.
Pitch Control
Changing the “pitch attitude” of the miniature aircraft or
fuselage dot by precise amounts in relation to the horizon
makes pitch changes. These changes are measured in degrees,
or fractions thereof, or bar widths depending upon the type of
attitude reference. The amount of deviation from the desired
performance determines the magnitude of the correction.
Bank Control
Bank changes are made by changing the “bank attitude”
or bank pointers by precise amounts in relation to the bank
scale. The bank scale is normally graduated at 0°, 10°, 20°,
30°, 60°, and 90° and is located at the top or bottom of the
attitude reference. Bank angle use normally approximates
the degrees to turn, not to exceed 30°.
Power Control
Proper power control results from the ability to smoothly
establish or maintain desired airspeeds in coordination
with attitude changes. Power changes are made by throttle
adjustments and reference to the power indicators. Power
indicators are not affected by such factors as turbulence,
improper trim, or inadvertent control pressures. Therefore,
in most aircraft little attention is required to ensure the power
setting remains constant.
Experience in an aircraft teaches a pilot approximately how
far to move the throttle to change the power a given amount.
Power changes are made primarily by throttle movement,
followed by an indicator cross-check to establish a more
precise setting. The key is to avoid fixating on the indicators
while setting the power. Knowledge of approximate power
settings for various flight configurations helps the pilot avoid
overcontrolling power.
Attitude Instrument Flying Using the Primary and
Supporting Method
Another basic method for teaching attitude instrument flying
classifies the instruments as they relate to control function,
as well as aircraft performance. All maneuvers involve some
degree of motion about the lateral (pitch), longitudinal (bank/
roll), and vertical (yaw) axes. Attitude control is stressed in
this handbook in terms of pitch control, bank control, power
control, and trim control. Instruments are grouped as they
relate to control function and aircraft performance as pitch
control, bank control, power control, and trim.
Pitch Control
Pitch control is controlling the rotation of the aircraft
about the lateral axis by movement of the elevators.
After interpreting the pitch attitude from the proper flight
instruments, exert control pressures to effect the desired pitch
attitude with reference to the horizon. These instruments
include the attitude indicator, altimeter, VSI, and airspeed
indicator. [Figure 6-4] The attitude indicator displays a
direct indication of the aircraft’s pitch attitude while the other
pitch attitude control instruments indirectly indicate the pitch
attitude of the aircraft.
Attitude Indicator
The pitch attitude control of an aircraft controls the angular
relationship between the longitudinal axis of the aircraft and
the actual horizon. The attitude indicator gives a direct and
immediate indication of the pitch attitude of the aircraft. The
aircraft controls are used to position the miniature aircraft
in relation to the horizon bar or horizon line for any pitch
attitude required. [Figure 6-5]
Figure 6-5. Attitude indicator.
30.0 29.9 29.8
Figure 6-6. Pitch correction using the attitude indicator.
30.0 29.9 29.8
Figure 6-7. Pitch correction using the altimeter.
Altimeter
If the aircraft is maintaining level flight, the altimeter
needles maintain a constant indication of altitude. If the
altimeter indicates a loss of altitude, the pitch attitude must
be adjusted upward to stop the descent. If the altimeter
indicates a gain in altitude, the pitch attitude must be
adjusted downward to stop the climb. [Figure 6-7] The
altimeter can also indicate the pitch attitude in a climb
or descent by how rapidly the needles move. A minor
adjustment in pitch attitude may be made to control the rate
at which altitude is gained or lost. Pitch attitude is used only
to correct small altitude changes caused by external forces,
such as turbulence or up and down drafts.
Vertical Speed Indicator (VSI)
In flight at a constant altitude, the VSI (sometimes referred
to as vertical velocity indicator or rate-of-climb indicator)
remains at zero. If the needle moves above zero, the pitch
attitude must be adjusted downward to stop the climb and
return to level flight. Prompt adjustments to the changes in
the indications of the VSI can prevent any significant change
in altitude. [Figure 6-8] Turbulent air causes the needle to
fluctuate near zero. In such conditions, the average of the
The miniature aircraft should be placed in the proper position
in relation to the horizon bar or horizon line before takeoff.
The aircraft operator’s manual explains this position. As soon
as practicable in level flight and at desired cruise airspeed,
the miniature aircraft should be moved to a position that
aligns its wings in front of the horizon bar or horizon line.
This adjustment can be made any time varying loads or other
conditions indicate a need. Otherwise, the position of the
miniature aircraft should not be changed for flight at other than
cruise speed. This is to make sure that the attitude indicator
displays a true picture of pitch attitude in all maneuvers.
When using the attitude indicator in applying pitch attitude
corrections, control pressure should be extremely light.
Movement of the horizon bar above or below the miniature
aircraft of the attitude indicator in an airplane should not
exceed one-half the bar width. [Figure 6-6] If further change
is required, an additional correction of not more than one-half
horizon bar wide normally counteracts any deviation from
normal flight.
Figure 6-8. Vertical speed indicator.
Figure 6-9. Pitch attitude has lowered.
fluctuations should be considered as the correct reading.
Reference to the altimeter helps in turbulent air because it is
not as sensitive as the VSI.
Vertical speed is represented in feet per minute (fpm).
[Figure 6-8] The face of the instrument is graduated with
numbers such as 1, 2, 3, etc. These represent thousands of feet
up or down in a minute. For instance, if the pointer is aligned
with .5 (1⁄2 of a thousand or 500 fpm), the aircraft climbs 500
feet in one minute. The instrument is divided into two regions:
one for climbing (up) and one for descending (down).
During turbulence, it is not uncommon to see large
fluctuations on the VSI. It is important to remember that small
corrections should be employed to avoid further exacerbating
a potentially divergent situation.
Overcorrecting causes the aircraft to overshoot the desired
altitude; however, corrections should not be so small that
the return to altitude is unnecessarily prolonged. As a guide,
the pitch attitude should produce a rate of change on the VSI
about twice the size of the altitude deviation. For example,
if the aircraft is 100 feet off the desired altitude, a 200 fpm
rate of correction would be used.
During climbs or descents, the VSI is used to change the altitude
at a desired rate. Pitch attitude and power adjustments are made
to maintain the desired rate of climb or descent on the VSI.
When pressure is applied to the controls and the VSI shows
an excess of 200 fpm from that desired, overcontrolling is
indicated. For example, if attempting to regain lost altitude at
the rate of 500 fpm, a reading of more than 700 fpm would
indicate overcontrolling. Initial movement of the needle
indicates the trend of vertical movement. The time for the VSI
to reach its maximum point of deflection after a correction is
called lag. The lag is proportional to speed and magnitude of
pitch change. In an airplane, overcontrolling may be reduced
by relaxing pressure on the controls, allowing the pitch attitude
to neutralize. In some helicopters with servo-assisted controls,
no control pressures are apparent. In this case, overcontrolling
can be reduced by reference to the attitude indicator.
Some aircraft are equipped with an instantaneous vertical
speed indicator (IVSI). The letters “IVSI” appear on the face
of the indicator. This instrument assists in interpretation by
instantaneously indicating the rate of climb or descent at a
given moment with little or no lag as displayed in a VSI.
Occasionally, the VSI is slightly out of calibration and
indicates a gradual climb or descent when the aircraft is
in level flight. If readjustments cannot be accomplished,
the error in the indicator should be considered when the
instrument is used for pitch control. For example, an
improperly set VSI may indicate a descent of 100 fpm when
the aircraft is in level flight. Any deviation from this reading
would indicate a change in pitch attitude.
Airspeed Indicator
The airspeed indicator gives an indirect reading of the
pitch attitude. With a constant power setting and a constant
altitude, the aircraft is in level flight and airspeed remains
constant. If the airspeed increases, the pitch attitude has
lowered and should be raised. [Figure 6-9] If the airspeed
decreases, the pitch attitude has moved higher and should
be lowered. [Figure 6-10] A rapid change in airspeed
indicates a large change in pitch; a slow change in airspeed
indicates a small change in pitch. Although the airspeed
indicator is used as a pitch instrument, it may be used in
level flight for power control. Changes in pitch are reflected
immediately by a change in airspeed. There is very little
lag in the airspeed indicator.
Figure 6-10. Pitch attitude has moved higher.
Figure 6-11. Bank instruments.
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Pitch Attitude Instrument Cross-Check
The altimeter is an important instrument for indicating pitch
attitude in level flight except when used in conditions of
exceptionally strong vertical currents, such as thunderstorms.
With proper power settings, any of the pitch attitude
instruments can be used to hold reasonably level flight
attitude. However, only the altimeter gives the exact altitude
information. Regardless of which pitch attitude control
instrument indicates a need for a pitch attitude adjustment,
the attitude indicator, if available, should be used to make
the adjustment. Common errors in pitch attitude control are:
• Overcontrolling;
• Improperly using power; and
• Failing to adequately cross-check the pitch attitude
instruments and take corrective action when pitch
attitude change is needed.
Bank Control
Bank control is controlling the angle made by the wing and
the horizon. After interpreting the bank attitude from the
appropriate instruments, exert the necessary pressures to
move the ailerons and roll the aircraft about the longitudinal
axis. As illustrated in Figure 6-11, these instruments include:
• Attitude indicator
• Heading indicator
• Magnetic compass
• Turn coordinator/turn-and-slip indicator
Attitude Indicator
As previously discussed, the attitude indicator is the only
instrument that portrays both instantly and directly the actual
flight attitude and is the basic attitude reference.
Heading Indicator
The heading indicator supplies the pertinent bank and heading
information and is considered a primary instrument for bank.
Magnetic Compass
The magnetic compass provides heading information and is
considered a bank instrument when used with the heading
indicator. Care should be exercised when using the magnetic
compass as it is affected by acceleration, deceleration in
flight caused by turbulence, climbing, descending, power
changes, and airspeed adjustments. Additionally, the
magnetic compass indication will lead and lag in its reading
depending upon the direction of turn. As a result, acceptance
of its indication should be considered with other instruments
that indicate turn information. These include the already
mentioned attitude and heading indicators, as well as the
turn-and-slip indicator and turn coordinator.