Introduction
Attitude instrument flying is defined as the control of an
aircraft’s spatial position by using instruments rather than
outside visual references. As noted in Section I, today’s
aircraft come equipped with analog and/or digital instruments.
Section II acquaints the pilot with the use of digital instruments
known as an electronic flight display (EFD).
The improvements in avionics coupled with the introduction
of EFDs to general aviation aircraft offer today’s pilot an
unprecedented array of accurate instrumentation to use in
the support of instrument flying.
Airplane Attitude
Instrument Flying
Chapter 6, Section II
Using an Electronic Flight Display
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270°
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NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
Fig 4-17 primary flight display (PFD)
DC ELEC
L R
Figure 6-21. Primary flight display (PFD) and analog counterparts.
Until recently, most general aviation aircraft were equipped
with individual instruments utilized collectively to safely
maneuver the aircraft by instrument reference alone. With
the release of the EFD system, the conventional instruments
have been replaced by multiple liquid crystal display (LCD)
screens. The first screen is installed in front of the left seat
pilot position and is referred to as the primary flight display
(PFD). [Figure 6-21] The second screen is positioned in
approximately the center of the instrument panel and is
referred to as the multifunction display (MFD). [Figure 6-22]
The pilot can use the MFD to display navigation information
(moving maps), aircraft systems information (engine
monitoring), or should the need arise, a PFD. [Figure 6-23]
With just these two screens, aircraft designers have been able
to declutter instrument panels while increasing safety. This
has been accomplished through the utilization of solid-state
instruments that have a failure rate far lower than those of
conventional analog instrumentation.
However, in the event of electrical failure, the pilot still
has emergency instruments as a backup. These instruments
either do not require electrical power, or as in the case
of many attitude indicators, they are battery equipped.
[Figure 6-24]
Pilots flying under visual flight rules (VFR) maneuver their
aircraft by reference to the natural horizon, utilizing specific
reference points on the aircraft. In order to operate the aircraft
in other than VFR weather, with no visual reference to the
natural horizon, pilots need to develop additional skills.
These skills come from the ability to maneuver the aircraft by
reference to flight instruments alone. These flight instruments
replicate all the same key elements that a VFR pilot utilizes
during a normal flight. The natural horizon is replicated on
the attitude indicator by the artificial horizon.
Understanding how each flight instrument operates and
what role it plays in controlling the attitude of the aircraft
is fundamental in learning attitude instrument flying. When
the pilot understands how all the instruments are used in
establishing and maintaining a desired aircraft attitude, the
pilot is better prepared to control the aircraft should one
or more key instruments fail or if the pilot should enter
instrument flight conditions.
Learning Methods
There are two basic methods utilized for learning attitude
instrument flying. They are “control and performance” and
“primary and supporting.” These methods rely on the same
flight instruments and require the pilot to make the same
adjustments to the flight and power controls to control aircraft
attitude. The main difference between the two methods is the
importance that is placed on the attitude indicator and the
interpretation of the other flight instruments.
Figure 6-22. Multifunction display (MFD).
Figure 6-23. Reversionary displays.
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27.3
NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
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MAP - NAVIGATION MAP
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18.0
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ALERTS
NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
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ALERTS
BACKUP PATH - AHRS using backup
data path.
TRAFFIC FAIL - Traffic device
has failed.
XPDR1 CONFIG - XPDR1 config
error. config service req’d.
TRAFFIC
Fig 4-19 reversionary mode (failed PFD)
Figure 6-24. Emergency back-up of the airspeed indicator, attitude indicator, and altitude indicator.
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NAV1 117.60 117.90
NAV2 117.90 117.60
132.675 120.000 COM1
118.525 132.900 COM2
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N-S
E-W
VOLTS
27.3
NAV1 117.60 117.90
NAV2 117.90 117.60
132.675 120.000 COM1
118.525 132.900 COM2
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MAP - NAVIGATION MAP
Figure 6-25. Control instruments.
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NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
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N-S
E-W
13.7
23.0
Figure 4-21. Control Instruments.
Control and Performance Method
Aircraft performance is accomplished by controlling the
aircraft attitude and power output. Aircraft attitude is the
relationship of its longitudinal and lateral axes to the Earth’s
horizon. When flying in instrument flight conditions, the
pilot controls the attitude of the aircraft by referencing the
flight instruments and manipulating the power output of the
engine to achieve the performance desired. This method can
be used to achieve a specific performance level enabling a
pilot to perform any basic instrument maneuver.
The instrumentation can be broken up into three different
categories: control, performance, and navigation.
Control Instruments
The control instruments depict immediate attitude and power
changes. The instrument for attitude display is the attitude
indicator. Power changes are directly reflected on the manifold
pressure gauge and the tachometer. [Figure 6-25] All three
of these instruments can reflect small adjustments, allowing
for precise control of aircraft attitude.
Figure 6-26. Performance instruments.
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NAV1 108.00 113.00
NAV2 108.00 110.60
134.000 118.000 COM1
123.800 118.000 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
N-S
E-W
13.7
23.0
Airspeed indicator
Vertical speed indicator
Heading indicator
Slip/skid indicator
Pitch indicator
In addition, the configuration of the power indicators installed
in each aircraft may vary to include the following types of
power indicators: tachometers, manifold pressure indicator,
engine pressure ratio indicator, fuel flow gauges, etc.
The control instruments do not indicate how fast the aircraft
is flying or at what altitude it is flying. In order to determine
these variables and others, a pilot needs to refer to the
performance instruments.
Performance Instruments
The performance instruments directly reflect the performance
the aircraft is achieving. The speed of the aircraft can be
referenced on the airspeed indicator. The altitude can be
referenced on the altimeter. The aircraft’s climb performance
can be determined by referencing the vertical speed indicator
(VSI). [Figure 6-26] Other performance instruments
available are the heading indicator, pitch attitude indicator,
and the slip/skid indicator.
The performance instruments most directly reflect a change
in acceleration, which is defined as change in velocity
or direction. Therefore, these instruments indicate if the
aircraft is changing airspeed, altitude, or heading, which are
horizontal, vertical, or lateral vectors.
Navigation Instruments
The navigation instruments are comprised of global
positioning system (GPS) displays and indicators, very high
frequency omnidirectional range/nondirectional radio beacon
(VOR/NDB) indicators, moving map displays, localizer, and
glideslope (GS) indicators. [Figure 6-27] The instruments
indicate the position of the aircraft relative to a selected
navigation facility or fix. Navigation instruments allow
the pilot to maneuver the aircraft along a predetermined
path of ground-based or spaced-based navigation signals
without reference to any external visual cues. The navigation
instruments can support both lateral and visual inputs.
The Four-Step Process Used to Change Attitude
In order to change the attitude of the aircraft, the pilot must
make the proper changes to the pitch, bank, or power settings
of the aircraft. Four steps (establish, trim, cross-check, and
adjust) have been developed in order to aid in the process.
Establish
Any time the attitude of the aircraft requires changing, the
pilot must adjust the pitch and/or bank in conjunction with
power to establish the desired performance. The changes
in pitch and bank require the pilot to reference the attitude
indicator in order to make precise changes. Power changes
should be verified on the tachometer, manifold pressure
gauge, etc. To ease the workload, the pilot should become
Figure 6-27. Navigation instruments.
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ALERTS
NAV1 117.60 117.90
NAV2 117.90 117.60
132.675 120.000 COM1
118.525 132.900 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
N-S
E-W
NAV1 117.60 117.90
NAV2 117.90 117.60
132.675 120.000 COM1
118.525 132.900 COM2
WPT _ _ _ _ _ _ DIS _ _ ._ NM DTK _ _ _° TRK 360°
MAP - NAVIGATION MAP
VOR 1
DME TUNING
DME MODE NAV1
Course deviation indicator
NAV controls
COM frequency window
NAV frequency window
COM controls
Com section
audio panel
NAV section
audio panel
DME tuning window
Glideslope/vertical guidance indicator
Moving map
VOR
GPS/NDB
familiar with the approximate pitch and power changes
necessary to establish a specified attitude.
Trim
Another important step in attitude instrument flying is
trimming the aircraft. Trim is utilized to eliminate the need
to apply force to the control yoke in order to maintain the
desired attitude. When the aircraft is trimmed appropriately,
the pilot is able to relax pressure on the control yoke and
momentarily divert attention to another task at hand without
deviating from the desired attitude. Trimming the aircraft is
very important, and poor trim is one of the most common
errors instructors note in instrument students.
Cross-Check
Once the initial attitude changes have been made, the pilot
should verify the performance of the aircraft. Cross-checking
the control and performance instruments requires the pilot
to visually scan the instruments, as well as interpret the
indications. All the instruments must be utilized collectively
in order to develop a full understanding of the aircraft attitude.
During the cross-check, the pilot needs to determine the
magnitude of any deviations and determine how much of a
change is required. All changes are then made based on the
control instrument indications.
Adjust
The final step in the process is adjusting for any deviations
that have been noted during the cross-check. Adjustments
should be made in small increments. The attitude indicator
and the power instruments are graduated in small increments
to allow for precise changes to be made. The pitch should be
made in reference to bar widths on the miniature airplane.
The bank angle can be changed in reference to the roll scale
and the power can be adjusted in reference to the tachometer,
manifold pressure gauge, etc.
By utilizing these four steps, pilots can better manage the
attitude of their aircraft. One common error associated with
this process is making a larger than necessary change when
a deviation is noted. Pilots need to become familiar with the
aircraft and learn how great a change in attitude is needed to
produce the desired performance.
Applying the Four-Step Process
In attitude instrument flight, the four-step process is used to
control pitch attitude, bank attitude, and power application of
the aircraft. The EFD displays indications precisely enough
that a pilot can apply control more accurately.
Pitch Control
The pitch control is indicated on the attitude indicator,which
spans the full width of the PFD. Due to the increased size
of the display, minute changes in pitch can be made and
corrected. The pitch scale on the attitude indicator is graduated
in 5-degree increments that allow the pilot to make corrections
with precision to approximately 1⁄2 degree. The miniature
airplane utilized to represent the aircraft in conventional
attitude indicators is replaced in glass panel displays by a
yellow chevron. [Figure 6-28] Representing the nose of the
aircraft, the point of the chevron affords the pilot a much
more precise indication of the degree of pitch and allows
the pilot to make small, precise changes should the desired
aircraft performance change. When the desired performance
is not being achieved, precise pitch changes should be made
by referencing the point of the yellow chevron.
Bank Control
Precise bank control can be developed utilizing the roll
pointer in conjunction with the roll index displayed on the
attitude indicator. The roll index is sectioned by hash marks at
0°, 10°, 20°, 30°, 45°, 60° and the horizon line, which depicts
90° of bank. [Figure 6-29] The addition of the 45° hash mark
is an improvement over conventional attitude indicators.
Figure 6-28. The chevron’s relationship to the horizon line indicates
the pitch of the aircraft.
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Figure 4-24. Pitch Control
Figure 6-29. Bank indicator index lines.
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0°
10°
20°
30°
45°
60°
Figure 4-25. Bank Control
In addition to the roll index, the instrument pilot utilizes
the turn rate indicator to maintain the aircraft in a standard
rate turn (3° per second). Most instrument maneuvers can
be done comfortably, safely, and efficiently by utilizing a
standard rate turn.
Power Control
The power instruments indicate how much power is being
generated by the engine. They are not affected by turbulence,
improper trim, or control pressures. All changes in power
should be made with reference to power instruments and
cross-checked on performance instruments.
Power control needs to be learned from the beginning of
flight training. Attitude instrument flying demands increased
precision when it comes to power control. As experience
increases, pilots begin to know approximately how much
change in throttle position is required to produce the desired
change in airspeed. Different aircraft demand differing
amounts of throttle change to produce specific performance.
It is imperative that the pilot make the specific changes on the
power instruments and allow the performance to stabilize.
Avoid the tendency to overcontrol.
One common error encountered with glass panel displays
is associated with the precision of the digital readouts.
This precision causes pilots to focus too much attention on
establishing the exact power setting.
Control and power instruments are the foundation for precise
attitude instrument flying. The keys to attitude instrument
flying are establishing the desired aircraft attitude on the
attitude indicator and selecting the desired engine output on
the power instruments. Cross-checking is the vital ingredient
in maintaining precise attitude instrument flight.
Attitude Instrument Flying—Primary and
Supporting Method
The second method for performing attitude instrument
flight is a direct extension of the control/power method.
By utilizing the primary and supporting flight instruments
in conjunction with the control and power instruments, the
pilot can precisely maintain aircraft attitude. This method
utilizes the same instruments as the control/power method;
however, it focuses more on the instruments that depict the
most accurate indication for the aspect of the aircraft attitude
being controlled. The four key elements (pitch, bank, roll,
and trim) are discussed in detail.
Similar to the control/power method, all changes to aircraft
attitude need to be made using the attitude indicator and the
power instruments (tachometer, manifold pressure gauge,
etc.). The following explains how each component of the
aircraft attitude is monitored for performance.