Pitot-Static System And Instruments - Cessna Grand Caravan 208B G1000 Manual

CESSNA SECTION 7
MODEL 208B G1000 AIRPLANE AND SYSTEMS DESCRIPTION

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, vertical
speed indicator, and 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 static pressure alternate 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 alternate 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.
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 de-ice/anti-ice switch panel, and two pull-off type circuit breaker,
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.
208BPHBUS-00 7-91
U.S.