Boeing B777 - Anti Ice and Rain
The pneumatic system isolation valves automatically open to maintain anti-icing to both wings if:
Whether the system is operating in Manual or Auto, if one wing anti-ice valve fails closed, the wing anti-ice system automatically closes the other valve to prevent asymmetrical wing anti-icing.
A backup anti-fogging system for the forward windows can be operated manually if there is a primary window heat system failure.
A backup anti-fogging system for the forward windows operates automatically if there is a primary window heat system failure.
When can wing anti-ice be operated manually?
When will the ANTI-ICE ON EICAS message be displayed?
A backup anti-fogging system for the flight deck windows operates automatically if there is a primary window heat system failure.
A backup anti-fogging system is available for the forward windows only: it operates automatically if there is a primary window heat system failure.
Each engine has a dual loop anti-ice system duct leak detection system. If an anti-ice duct leak is detected:
Only the forward windows have exterior surface anti-icing. The forward windows have exterior and interior surface anti-fogging protection. The side windows have interior surface anti-fogging protection only.
If the total air temperature (TAT) is above 10 deg.C, both Manual and Automatic wing anti-ice operation is inhibited for:
The TAT inhibit is removed any time TAT drops below 10 deg.C.
With the WING ANTI-ICE selectors set to AUTO in flight, the wing anti-icing valves open when icing conditions exist and bleed air pressure is available.
The bleed air for Engine Anti-ice comes directly from the associated engine and not from the Pneumatic System ducting.
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The automatic ice detection system consists of:
The detector probes normally vibrate when the detection system is operating. If ice accumulates on a probe, the probe will vibrate at a lower frequency. The probe heater will turn on to melt the ice until the vibration frequency returns to normal. Once a detector probe has ice build-up, it is automatically de-iced.
The AOA vanes are heated:
The AOA has only one temperature level.
There are no controls for the operation of Probe Heat.
Indications are provided on the EICAS when one or more probe heaters are not operating.
When a Wing Anti-ice Valve is open, the wing anti-ice (WAI) annunciation is displayed below the EICAS N1 indication.
With Engine Anti-ice On, the display of "EAI" appears ___________ the N1 displays.
An additional wing anti-ice inhibit for Automatic Wing Anti-ice operation (independent of the TAT inhibit), is active during the takeoff phase of flight.
Automatic wing anti-ice operation is inhibited for 10 minutes after takeoff. Manual wing anti-ice operation is not affected by this inhibit.
There are three angle-of-attack (AOA) sensors, mounted aft of and above the pitot probes on each side of the fuselage.
What does the WINDOW HEAT EICAS message mean?
Probe Heat automatically operates when either engine is operating.
The level of heat provided to the pitot probes is automatically set a lower level on the ground to protect from over heating the elements. Full heat level is provided in flight.
The Wing Anti-ice system operates through the delivery of hot air to the three midwing slats.
The hot air for wing anti-ice is provided by the pneumatic system.
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What do the EAI symbols on EICAS indicate?
Which windows are provided with backup anti-fog heat?
Windshield Heat is provided by electric resistance coatings.
When can engine anti-ice be operated manually?
Which windows are provided with backup anti-fog heat?
The engine anti-ice systems operate through the delivery of bleed air to the inlet cowl. The hot air for engine anti-ice is provided:
What occurs when engine anti-ice is operating?
Window heat - An INOP light illuminates in the respective switch when:
What is the position of an engine anti-ice valve when the ENGINE ANTI-ICE selector is in AUTO and the EAI is displayed?
What does the WINDOW HEAT R FWD EICAS message mean?
The Wing Anti-ice system is controlled by the Wing Anti-ice switch. The switch has 3 positions. The bleed air for Wing Anti-ice comes from the Pneumatic System ducting and flows to each wing through:
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When the Engine Anti-ice is on (either in the Auto or Manual mode), the engine is selected to: Approach Idle by the EEC.
The Windshield Wiper for each pilot is controlled by a 3 position rotary switch on the respective side of the forward Overhead Panel.
The windshield wiper for each pilot is controlled by a 4 position rotary switch on the respective side of the forward overhead panel.