787 Flight Crew Operations Manual
DO NOT USE FOR FLIGHT
Anti-Ice, Rain -
System Description
Copyright © The Boeing Company. See title page for details.
3.20.2 D615Z003-TBC
The engine anti-ice valves close automatically:
• during start
• for bleed air overtemperature
• for bleed air overpressure
• when an engine fire switch is pulled
• when a bleed air leak is detected
Engine Anti–Ice Leak Detection System
Each engine has an anti–ice system duct leak detection system. If an anti–ice duct
leak is detected, the respective engine anti–ice valve closes.
Wing Anti–Ice System
The electric wing anti–ice system powers thermal anti-icing mats on four midwing
leading edge slats on each wing. There are three separate mats on each slat. Wing
anti–ice is inhibited on the ground below 80 knots. Wing anti-ice may be
momentarily shed (30 seconds maximum) during high electrical loads, such as
during flap retraction. To maintain aerodynamic stability, system logic controls
symmetrical operation of left and right wing anti-ice.
The wing anti–ice annunciation WAI is displayed below the EICAS N1 indication
when wing anti–ice is powered.
Wing Anti–Ice System Automatic Operation
In flight, when the WING ANTI–ICE selector is in AUTO, wing anti–ice system
operation is automatic. When icing conditions are detected, power is supplied to
the thermal mats on the leading edge slats. When ice is no longer detected, power
is removed. If one wing anti–ice thermal mat fails, the wing anti–ice system
automatically de-powers the opposite thermal mat to prevent asymmetrical wing
icing.
Automatic wing anti–ice operation is available in flight and on the ground above
80 knots airspeed.
Wing Anti–Ice System Manual Operation
In flight, when the WING ANTI–ICE selector is ON the wing anti–ice system on
each wing is powered anytime TAT is below 10º C.
Pack Inlet Anti-Ice System
The pack inlet anti-ice system provides ice protection for both ram air inlets for
the cabin air compressors. An electric heater on the leading edge of each inlet
prevents ice formation and reduces ice formation in the duct during icing
conditions.
February 15, 2010
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