Section 7
Description of the Airplane and Systems
Columbia 400 (LC41-550FG)
RC050002
Initial Issue of Manual: November 10, 2004
7-28
Latest Revision Level/Date: -/11-10-2004
functional for IFR operations. Pressing the test switch on the audio panel that tests the audio
panel lights will also test the remote marker beacon lights.
Airspeed Indicator –
The backup airspeed indicator is part of the pitot-static system, which is
discussed on page 7-50. The instrument measures the difference between total pressure and static
pressure and, through a series of mechanical linkages, displays an airspeed indication. The
source of the ram pressure is from the pitot tube, and the source of the static pressure is from the
static air vent. The instrument shows airspeed in knots on the outer circumference of the
instrument, which ranges from 0 to 260 knots with 10-knot increments. Airspeed limitations in
KIAS are shown on colored arcs as follows: white arc – 60 to 117 knots; green arc – 73 to 181
knots; yellow arc – 181 to 230 knots; and red line – 230 knots.
True airspeed (TAS) is obtainable for indicated airspeeds between 135 and 215 knots by
reference to the true airspeed ring on the outer portion of the dial, approximately between the
five thirty and ten o’clock positions. The adjustment knob for this function is near the five
o’clock position on the airspeed indicator. Moving the knob causes the pressure altitude scale in
a window at the top of the instrument to move under a stationary temperature scale. Rotate the
knob until the pressure altitude (in increments of 1000 feet) is opposite the temperature (
°
C in
increments of 10
°
), and read the TAS on the true airspeed ring. Greater accuracy is produced if
calibrated airspeed is used rather than indicated airspeed.
Attitude Indicator
–
The backup attitude indicator is electrically powered and protected by a
three-amp circuit breaker. The instrument uses a self-contained vertical gyroscope mounted on a
pitch gimbal that is mounted on a roll gimbal. The gyro provides information relating to
movement around the pitch and roll axes. The indicator is capable of operation through 360
degrees of aircraft pitch and roll displacement. The instrument has a caging knob that provides
simultaneous erection of the pitch and roll axes. The instrument has a power warning flag on the
upper right side of the instrument. When the flag is in view, power is off. When retracted, normal
operation is indicated.
To cage the instrument pull the “PULL TO CAGE” knob to the fully extended position until the
display stabilizes, then carefully allow the knob to quickly return to the inward position avoiding
a snap release. The instrument does not normally need to be caged prior to takeoff. If necessary,
the instrument may be caged prior to takeoff. In the event of excessive attitude errors caused by
extended bank, acceleration or deceleration, the indicator should be momentarily caged after the
aircraft is returned to level flight.