Figure 6-30. Pitch of the aircraft.
XPDR 5537 IDNT LCL23:00:34
VOR 1
270°
TAS 100KT
OAT 7°C
ALERTS
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
Artificial horizon
Slip/skid indicator
Pitch attitude of aircraft
Pitch Control
The pitch of the aircraft refers to the angle between the
longitudinal axis of the aircraft and the natural horizon. When
flying in instrument meteorological conditions (IMC), the
natural horizon is unavailable for reference and an artificial
horizon is utilized in its place. [Figure 6-30] The only
instrument capable of depicting the aircraft attitude is the
attitude indicator displayed on the PFD. The attitude and
heading reference system (AHRS) is the engine that drives
the attitude display. The AHRS unit is capable of precisely
tracking minute changes in the pitch, bank, and yaw axes,
thereby making the PFD very accurate and reliable. The
AHRS unit determines the angle between the aircraft’s
longitudinal axis and the horizon line on initialization. There
is no need or means for the pilot to adjust the position of the
yellow chevron, which represents the nose of the aircraft.
Straight-and-Level Flight
In straight-and-level flight, the pilot maintains a constant
altitude, airspeed and, for the most part, heading for extended
periods of time. To achieve this, the three primary instruments
that need to be referenced in order to maintain these three
variables are the altitude, airspeed, and heading indicators.
Primary Pitch
When the pilot is maintaining a constant altitude, the primary
instrument for pitch is the altimeter. As long as the aircraft
maintains a constant airspeed and pitch attitude, the altitude
should remain constant.
Two factors that cause the altitude to deviate are turbulence
and momentary distractions. When a deviation occurs, a
change in the pitch needs to be made on the attitude indicator.
Small deviations require small corrections, while large
deviations require larger corrections. Pilots should avoid
making large corrections that result in rapid attitude changes,
for this may lead to spatial disorientation. Smooth, timely
corrections should be made to bring the aircraft back to the
desired attitude.
Pay close attention to indications on the PFD. An increase
in pitch of 2.5° produces a climb rate of 450 feet per minute
(fpm). Small deviations do not require large attitude changes.
A rule of thumb for correcting altitude deviations is to
establish a change rate of twice the altitude deviation, not to
exceed 500 fpm. For example, if the aircraft is off altitude
by 40 feet, 2 × 40 = 80 feet, so a descent of approximately
100 fpm allows the aircraft to return to the desired altitude
in a controlled, timely fashion.
In addition to the primary instrument, there are also
supporting instruments that assist the pilot in cross-checking
the pitch attitude. The supporting instruments indicate trend,
but they do not indicate precise attitude indications. Three
instruments (vertical speed, airspeed, and altitude trend
tape) indicate when the pitch attitude has changed and that
the altitude is changing. [Figure 6-31] When the altitude is
constant, the VSI and altitude trend tape are not shown on
the PFD. When these two trend indicators are displayed, the
Figure 6-31. Supporting instruments.
VOR 1
270°
-500
TAS 100KT
Figure 4-27. Supporting Instruments
270°
-125
-250
-375
Altitude trend vector
Turn rate trend vector
Airspeed trend (increasing)
Figure 6-32. Primary bank.
XPDR 5537 IDNT LCL23:00:34
13.7
23.0
VOR 1
270°
TAS 100KT
ALERTS
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°
Roll scale zero
Slip/skid indicator
Skidding turn
270°
Roll pointer
Standard rate
Heading
1/2 standard rate
Turn rate trend vector
regarding the direction and rate of altitude deviations. The
pilot is thus able to make corrections to the pitch attitude
before a large deviation in altitude occurs. The airspeed
indicator depicts an increase if the pitch attitude is lowered.
Conversely, when the pitch attitude increases, the pilot should
note a decrease in the airspeed.
Primary Bank
When flying in IMC, pilots maintain preplanned or assigned
headings. With this in mind, the primary instrument for bank
angle is the heading indicator. Heading changes are displayed
instantaneously. The heading indicator is the only instrument
that displays the current magnetic heading, provided that
it is matched to the magnetic compass with all deviation
adjustments accounted for. [Figure 6-32]
There are supporting instruments associated with bank as
well. The turn rate trend indicator shows the pilot when the
aircraft is changing heading. The magnetic compass is also
useful for maintaining a heading; however, it is influenced
by several errors in various phases of flight.
Primary Yaw
The slip/skid indicator is the primary instrument for yaw.
It is the only instrument that can indicate if the aircraft is
pilot is made aware that the pitch attitude of the aircraft has
changed and may need adjustment. Notice in Figure 6-31
that the aircraft is descending at a rate of 500 fpm.
The instrument cross-check necessitates utilizing these
supporting instruments to better manage altitude control.
The VSI and trend tape provide the pilot with information
to include the stand-by flight instruments as well as the
engine indications in the scan. Due to the size of the
attitude instrument display, scanning techniques have been
simplified because the attitude indicator is never out of
peripheral view.
Selected Radial Cross-Check
The radial scan is designed so that your eyes remain on the
attitude indicator 80–90 percent of the time. The remainder
of the time is spent transitioning from the attitude indicator
to the various other flight instruments. [Figure 6-33]
The radial scan pattern works well for scanning the PFD. The
close proximity of the instrument tape displays necessitates
very little eye movement in order to focus in on the desired
instrument. While the eyes move in any direction, the
extended artificial horizon line allows the pilot to keep the
pitch attitude in his or her peripheral vision. This extended
horizon line greatly reduces the tendency to fixate on one
instrument and completely ignore all others. Because of
the size of the attitude display, some portion of the attitude
indicator is always visible while viewing another instrument
display on the PFD.
Starting the Scan
Start the scan in the center of the PFD on the yellow chevron.
Note the pitch attitude and then transition the eyes upward to
the slip/skid indicator. Ensure that the aircraft is coordinated
by aligning the split triangle symbol. The top of the split
triangle is referred to as the roll pointer. The lower portion of
the split triangle is the slip/skid indicator. If the lower portion
of the triangle is off to one side, step on the rudder pedal on
the same side to offset it. [Figure 6-34 NOTE: The aircraft
is not changing heading. There is no trend vector on the turn
rate indicator.]
While scanning that region, check the roll pointer and assure
that the desired degree of roll is being indicated on the bank
scale. The roll index and the bank scale remain stationary at
the top of the attitude indicator. The index is marked with
angles of 10°, 20°, 30°, 45°, and 60° in both directions. If
the desired bank angle is not indicated, make the appropriate
aileron corrections. Verify the bank angle is correct and
continue scanning back to the yellow chevron.
Scan left to the airspeed tape and verify that the airspeed is
as desired, then return back to the center of the display. Scan
right to the altimeter tape. Verify that the desired altitude
is being maintained. If it is not, make the appropriate pitch
change and verify the result. Once the desired altitude has been
verified, return to the center of the display. Transition down to
the heading indicator to verify the desired heading. When the
heading has been confirmed, scan to the center of the display.
moving through the air with the longitudinal axis of the
aircraft aligned with the relative wind.
Primary Power
The primary power instrument for straight-and-level flight is
the airspeed indicator. The main focus of power is to maintain
a desired airspeed during level flight. No other instrument
delivers instantaneous indication.
Learning the primary and supporting instruments for
each variable is the key to successfully mastering attitude
instrument flying. At no point does the primary and supporting
method devalue the importance of the attitude indicator or the
power instruments. All instruments (control, performance,
primary, and supporting) must be utilized collectively.
Fundamental Skills of Attitude Instrument
Flying
When first learning attitude instrument flying, it is very
important that two major skills be mastered. Instrument cross-
check and instrument interpretation comprise the foundation
for safely maneuvering the aircraft by reference to instruments
alone. Without mastering both skills, the pilot is not able to
maintain precise control of aircraft attitude.
Instrument Cross-Check
The first fundamental skill is cross-checking (also call
“scanning”). Cross-checking is the continuous observation of
the indications on the control and performance instruments.
It is imperative that the new instrument pilot learn to
observe and interpret the various indications in order to
control the attitude and performance of the aircraft. Due to
the configuration of some glass panel displays, such as the
Garmin G1000, one or more of the performance instruments
may be located on an MFD installed to the right of the pilot’s
direct forward line of sight.
How a pilot gathers the necessary information to control
the aircraft varies by individual pilot. No specific method of
cross-checking (scanning) is recommended; the pilot must
learn to determine which instruments give the most pertinent
information for any particular phase of a maneuver. With
practice, the pilot is able to observe the primary instruments
quickly and cross-check with the supporting instruments
in order to maintain the desired attitude. At no time during
instrument flying should the pilot stop cross-checking
the instrumentation.
Scanning Techniques
Since most of the primary and supporting aircraft attitude
information is displayed on the PFD, standard scanning
techniques can be utilized. It is important to remember
Figure 6-33. Selected radial cross-check.
XPDR 5537 IDNT LCL23:00:34
13.7
23.0
VOR 1
270°
TAS 100KT
ALERTS
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°
Figure 4-30. Selected Radial Cross-Check
Slip/skid indicator
Heading
Airspeed indicator
Altitude indicator
Vertical speed indicator
Artificial horizon
Pitch Attitude
Slip/skid indicator
Airspeed indicator
Altitude indicator/VSI
Heading indicator
SCAN PATTERN
Scan pattern should start with
left (airspeed indicator), then
right (altitude indicator/VSI),
then up (slip/skid indicator),
then down (heading indicator).
The pilot should return attention
back to the center (pitch
attitude) before proceeding to
the next direction. For example:
left, center, right, center, up,
center, down, center.
XPDR 5537 IDNT LCL23:00:34
13.7
23.0
VOR 1
270°
TAS 100KT
ALERTS
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°
Figure 4-31. Starting the Scan
Roll pointer
Slip/skid indicator
Rudder
Figure 6-34. Roll pointer and slip/skid indicator.
TAS 120KT
Figure 4-32. Airspeed Trend Indicators
TAS 120KT
Airspeed trend indicator
shows airspeed will be
approximately 126 kts in
6 seconds.
Figure 6-35. Airspeed trend indicators.
Figure 6-36. Airspeed indicators with no trend present.
TAS 120KT
Figure 4-33. Airspeed Indicators No trend present
Airspeed indicator
showing stabilized
airspeed (no trend
indicator present).
Figure 6-37. Altimeter trend indicators.
Figure 4-34. Altimeter Trend Indicators
Trend indicator shows
altitude will be approxi-
mately 1,780 ft in 6
seconds.
VSI arrow has moved up
to indicate a 1,500 fpm
rate of climb.
Note
1,500 fpm ÷ 60 sec = 25 ft
25 ft per sec x 6 sec = 150 ft
150 ft + 1,630 ft = 1,780 ft
20 16
It is also important to include the engine indications in the
scan. Individualized scan methods may require adjustment
if engine indications are presented on a separate MFD. A
modified radial scan can be performed to incorporate these
instruments into the scan pattern. Another critical component
to include in the scan is the moving map display located on
the MFD. To aid in situational awareness and facilitate a
more centralized scan, a smaller inset map can be displayed
in the lower left corner of the PFD screen.
Trend Indicators
One improvement the glass panel displays brought to the
general aviation industry is the trend vector. Trend vectors
are colored lines that appear on the airspeed and altitude
tapes, as well as on the turn rate indicator. The color of
the line may vary depending on the airplane manufacturer.
For example, on a Cirrus SR-20, the trend vector lines are
magenta and on the B-737 they are green. These colored lines
indicate what the associated airspeed, altitude, or heading
will be in 6 seconds for the Cirrus SR-20 and 10 seconds
for the B-737 if the current rate is maintained. The example
shown in Figure 6-35 uses the color and data that represents
the trend vector for a Cirrus SR-20. The trend vector is not
displayed if there is no change to the associated tape and the
value remains constant [Figure 6-36] or if there is a failure
in some portion of the system that would preclude the vector
from being determined.
Trend vectors are a very good source of information for the
new instrument rated pilot(s). Pilots who utilize good scanning
techniques can pick up subtle deviations from desired
parameters and make small correction to the desired attitude.
As soon as a trend is indicated on the PFD, a conscientious
pilot can adjust to regain the desired attitude. [Figure 6-37]
Another advancement in attitude instrument flying is the
turn rate trend indicator. As in the cases of airspeed, altitude,
and vertical speed trend indicators, the turn rate trend
indicator depicts what the aircraft’s heading will be in 6
seconds. While examining the top of the heading indicator,
notice two white lines on the exterior of the compass rose.
[Figure 6-38] These two tick marks located on both sides
of the top of the heading indicator show half-standard rate
turns as well as standard rate turns.
In Figure 6-39, when the aircraft begins its turn to the left,
the magenta trend indicator elongates proportionally with the
rate of turn. To initiate a half-standard rate turn, position the
XPDR 5537 IDNT LCL23:00:34
GPS TERM
197°
357°HDG 152°CRS
TAS 120KT
OAT 7°C
ALERTS
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°
TRAFFIC
Figure 4-35. HSI Trend Indicator elongates proportionate to the rate of turn.
Heading
1/2 standard rate
Standard rate
Turn rate trend vector
Figure 6-38. Horizontal situation indicator (HSI) trend indicator elongates proportionally with the rate of turn.
VOR1
197°
357°HDG 152°CRS
Figure 4-36. HSI Trend Indicator elongates proportionate to the
rate of turn (enlarge).
Heading
1/2 standard rate
Standard rate
Turn rate trend vector
Figure 6-39. HSI indicator (enlargement).
indicator on the first tick mark. A standard rate turn would
be indicated by the trend indicator extending to the second
tick mark. A turn rate in excess of standard rate would be
indicated by the trend indicator extending past the second tick
mark. This trend indicator shows what the aircraft’s heading
will be in 6 seconds, but is limited to indicate no more than
24° in front of the aircraft or 4° per second. When the aircraft
exceeds a turning rate of 25° in 6 seconds, the trend indicator
has an arrowhead attached to it.
Trend indicators are very useful when leveling off at a specific
altitude, when rolling out on a heading, or when stabilizing
airspeed. One method of determining when to start to level
off from a climb or descent is to start leveling at 10 percent
of the vertical speed rate prior to the desired altitude.
As the aircraft approaches the desired altitude, adjust the
pitch attitude to keep the trend indicator aligned with the
target altitude. As the target approaches, the trend indicator
gradually shrinks until altitude stabilizes. Trend indicators
should be used as a supplement, not as a primary means of
determining pitch change.
Common Errors
Fixation
Fixation, or staring at one instrument, is a common error
observed in pilots first learning to utilize trend indicators.
The pilot may initially fixate on the trend indicator and make
adjustments with reference to that alone. Trend indicators are
not the only tools to aid the pilot in maintaining the desired
power or attitude; they should be used in conjunction with the
primary and supporting instruments in order to better manage
the flight. With the introduction of airspeed tapes, the pilot
can monitor airspeed to within one knot. Fixation can lead
to attempting to keep the airspeed to an unnecessarily tight
tolerance. There is no need to hold airspeed to within one
knot; the Instrument Rating Practical Test Standards (PTS)
allows greater latitude.
Omission
Another common error associated with attitude instrument
flying is omission of an instrument from the cross-check. Due
to the high reliability of the PFD and associated components,
pilots tend to omit the stand-by instruments as well as the
magnetic compass from their scans. An additional reason
for the omission is the position of the stand-by instruments.
Pilots should continue to monitor the stand-by instruments
in order to detect failures within those systems. One of the
most commonly omitted instruments from the scan is the
slip/skid indicator.
Emphasis
In initial training, placing emphasis on a single instrument
is very common and can become a habit if not corrected.
When the importance of a single instrument is elevated above
another, the pilot begins to rely solely on that instrument
for guidance. When rolling out of a 180° turn, the attitude
indicator, heading indicator, slip/skid indicator, and altimeter
need to be referenced. If a pilot omits the slip/skid indicator,
coordination is sacrificed.