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accumulated ice, allowing the frequency to again increase to 40,000 Hz, shutting off
probe heat. If the probe is still free of ice sixty (60) seconds later, the ICE DETECTED
CAS message is removed, indicating the airplane is clear of icing conditions.
There are also production provisions for an ice detector “ICE DET” test button on the
TEST panel (copilot side of center console [SN 1457 and subs]).
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS 2A-30-00
Page 1
October 11/02
Revision 8
2A-30-20: Wing Anti-Ice System
1. General Description:
The wing anti-ice system provides ice protection for each wing by warming the
leading edge with engine bleed air from the bleed air manifold. It consists of
identical, independently operating left and right sides, each side having a tap into
the bleed air manifold. Although separate and independent, the left and right sides
are joined by a crossover duct installed downstream of the wing anti-ice control
valves. This duct allows one side of the system to provide anti-ice protection for
both wing leading edges.
The following units and components together compose this system:
• Engine Bleed Air Manifold
• Anti-Ice Sensors
• Anti-Ice Controllers
• Anti-Ice Servo Air Pressure Regulator and Torque Motors
• Anti-Ice Control Valves
• System Ducts and Piccolo Tubes
• Normal and Overheat Thermal Switches
2. Description of Subsystems, Units and Components:
A. Engine Bleed Air Manifold:
The engine bleed air manifold is supplied mid-stage air from each engine’s
7th stage compressor section through the 7th stage check valve.
Depending on conditions, high-stage air may also be supplied by each
engine’s 12th stage compressor through the 12th stage air control valve
(often referred to as the HP valve).
In addition to supplying air for wing anti-icing, air from the bleed air
manifold is used for crossbleed starting and airplane services such as air
conditioning and pressurization.
B. Anti-Ice Sensors:
A wing anti-ice sensor is installed on the front beam (spar) of each wing to
sense the temperature in the leading edge plenum. Each sensor is a
thermistor, thus its resistance varies proportionally to its temperature.
With the wing anti-ice system operating, each sensor sends its associated
anti-ice controller a low voltage signal that is proportional to the sensed
temperature.
C. Anti-Ice Controllers:
Each anti-ice controller receives power from the Essential 28 VDC bus.
The controllers receive low voltage signals from its associated anti-ice
sensor, then convert that signal into a high output signal to command its
associated anti-ice servo air pressure regulator and torque motor.
D. Anti-Ice Servo Air Pressure Regulator and Torque Motors:
The anti-ice servo air pressure regulator and torque motor controls the
pressure to its associated anti-ice control valve using an electrical signal
received from its associated anti-ice controller. The electrical signal is then
converted into a pneumatic signal used to position the anti-ice control valve
proportionally.
OPERATING MANUAL
2A-30-00 PRODUCTION AIRCRAFT SYSTEMS
Page 2
October 11/02
Revision 8
E. Anti-Ice Control Valves:
The anti-ice control valve is spring loaded closed and pneumatically
powered open. It is electrically controlled by its associated (L/R) WING
switch in the ANTI ICE section of the cockpit overhead panel. With the
WING switch selected ON, the ON legend in the switch illuminates and a
blue (L/R) WING A/I advisory message is displayed on CAS. The control
valve is allowed to open and begins to seek a position determined by the
pressure downstream of its associated servo air pressure regulator and
torque motor. The control valve regulates wing leading edge temperature
by controlling bleed air flow to its associated system ducts and piccolo
tube. It also regulates downstream pressure to 23 psi any time upstream
pressure exceeds this value.
F. System Ducts and Piccolo Tubes:
During normal operation, the left and right wing anti-ice systems are
isolated from each other (upstream of the crossover duct) by the isolation
valve. The left engine bleed air system supplies the left wing anti-ice
system and the right engine bleed air system supplies the right wing antiice
system. This isolation eliminates the problem two-engine flow-sharing.
Should one engine bleed air system fail, however, opening the isolation
valve allows the operative engine bleed air system to supply air to both
wing anti-ice systems.
A crossover duct is installed downstream of the anti-ice control valves to
　
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