Pitot-Static System And Instruments - Textron Cessna Grand Caravan Ex 208B Pilot's Operating Handbook And Faa Approved Airplane Flight Manual

SECTION 7 CESSNA
AIRPLANE AND SYSTEMS DESCRIPTION MODEL 208B 867 SHP
GARMIN G1000

PITOT-STATIC SYSTEM AND INSTRUMENTS

There are two independent pitot-static systems on the airplane. The left
pitot-static system supplies ram air pressure to Air Data Computer #1
and to the standby airspeed indicator, and supplies static pressure to
Air Data Computer 1 and to the standby airspeed indicator and standby
altimeter. The right pitot-static system provides ram air and static
pressure to Air Data Computer 2. Each system is composed of a
heated pitot-static tube mounted on the leading edge of the
corresponding wing, a drain valve located on the sidewall beneath the
instrument panel, and the associated plumbing necessary to connect
the instruments and sources. In addition, the left system includes a ALT
STATIC AIR source valve located on the lower left corner of the
instrument panel.
The static pressure alternate source valve in the left system can be
used if the static source is malfunctioning. This valve supplies static
pressure from inside the cabin instead of from the pitot-static tube. If
erroneous instrument readings are suspected due to water or ice in the
pressure line going to the static pressure source, the ALT STATIC AIR
source valve should be PULLED ON. Pressures within the cabin will
vary with vents open or closed. Refer to Section 5, Performance for the
effect of varying cabin pressures on airspeed and altimeter readings.
The drain valves incorporated in each system, located on the sidewall
beneath the instrument panel, are used to drain suspected moisture
accumulation by lifting the drain valve lever to the OPEN position as
indicated by the placard adjacent to the valve. The valve must be
returned to the CLOSED position prior to flight.
A left and right pitot-static heat system is installed to assure proper
airspeed indications in the event icing conditions are encountered. The
system is designed to prevent ice formation rather than remove it. The
pitot-static heat system consists of a heating element in each
pitot-static tube, a two-position toggle switch, labeled PITOT/STATIC
HEAT, on the ANTI-ICE switch panel, and two pull-off type circuit
breakers, labeled LEFT PITOT HEAT and RIGHT PITOT HEAT, on the
left sidewall switch and circuit breaker panel. When the PITOT-STATIC
HEAT switch is turned ON, elements in the pitot-static tubes are heated
electrically to maintain proper operation in possible icing conditions.
Both pitot and static systems are monitored by the G1000 system for
insufficient current and alerting is provided to the flight crew by a single
chime and an amber L P/S HEAT, R P/S HEAT, or L-R P/S HEAT
annunciator.
7-114 208BPHCUS-00
U.S.