S
ECTION
7: A
IRPLANE
AND
S
YSTEMS
C
IRRUS
D
ESIGN
F
LIGHT
I
NSTRUMENTS
SR20
7-18
P/N 11934-005
Attitude Indicator
The primary attitude indicator is shown on the upper center of the PFD and
displays pitch, roll, and slip/skid information provided by the Attitude and
Heading Reference System (AHRS).
Above and below the horizon line, major pitch marks and labels are shown
for every 10°, up to 80°. Between 25° below and 45° above the horizon line,
the pitch index scale is graduated in 5° increments with every 10° of pitch
labeled. Between 20° below and 20° above the horizon line, minor pitch
marks occur every 2.5°. If pitch limits are exceeded in either the nose-up or
nose-down attitude, red warning chevrons will appear and point the way
back to level flight. The roll index scale is graduated with major tick marks
at 30° and 60° and minor tick marks at 10°, 20°, and 45°. The roll pointer is
slaved to the airplane symbol. The slip-skid indicator is the bar beneath the
roll pointer. The indicator moves with the roll pointer and moves laterally
away from the pointer to indicate lateral acceleration. Slip/skid is indicated
by the location of the bar relative to the pointer. One bar displacement is
equal to one ball displacement on a traditional slip/skid indicator.
Standby Attitude Indicator
Serials w/o MD302 Standby Attitude Module:
The standby attitude indicator is mounted on the LH bolster panel and
provides backup indication of flight attitude. Bank attitude is indicated by
a pointer at the top of the indicator relative to the bank scale with index
marks at 10°, 20°, 30°, 60°, and 90° either side of the center mark. A fixed
miniature airplane superimposed over a movable mask containing a white
symbolic horizon bar, which divides the mask into two sections, indicates
pitch and roll attitudes. The upper “blue sky” section and the lower “earth”
sections have pitch reference lines useful for pitch attitude control. A knob
at the bottom of the instrument allows adjustment of the miniature
airplane to the horizon bar for a more accurate flight attitude indication. A
PULL TO CAGE knob on the indicator is used for quick erection of the
gyro. When the caging knob is pulled, the pitch and roll indications will
align to within 2° of their respective fixed references. The standby attitude
indicator is electrically driven. A red GYRO flag indicates loss of electrical
power. Redundant circuits paralleled through diodes at the indicator
supply DC electrical power for gyro operation.
Serials w/ MD302 Standby Attitude Module:
The MD302 Standby Attitude Module is mounted on the LH bolster panel
and gives backup indication of flight attitude. Bank attitude is indicated by
a pointer at the top of the indicator relative to the bank scale with index
marks at 0° (triangle), 10°, 20°, 30°, 45° (small triangle), and 60° either side
of the center mark. A fixed, user-configurable airplane symbol is superim-
posed over a movable background containing a white horizon bar that
divides the attitude display into two sections: upper “blue sky” and lower
Reissue A
