Anti-Ice and Rain - Wings

Wing Anti-Ice System

Anti-Icing Control Panel.

The wing anti-ice system provides Bleed Air to the three mid-wing Leading Edge Slats on each wing. Wing anti-ice can be operated in flight only. It is inhibited on the ground by the Air/Ground Logic System.

Wing Anti-Ice System Operation

Wing anti-ice schematic Engine (Cowl) Anti-Ice Wing Anti-Ice Valve

In flight, pushing the WING ANTI-ICE switch ON opens the wing anti-ice valve in each wing, allowing bleed air to flow from the bleed air manifold to the affected Slats. Pushing the WING ANTI-ICE switch again commands the wing anti-ice valve in each wing to close, stopping bleed air from flowing from the bleed air manifold to the affected Slats.

If a landing is made with the switch ON, the Air/Ground Logic System automatically closes the wing anti-ice valves.

The VALVE light illuminates and the EICAS advisory message L/R WING ANTI-ICE displays if the Wing Anti-Ice valve disagrees with the switch position.

Maximum EPR is automatically reduced when wing anti-ice is in use. (Note: The adjustment is based on switch position, not the position of the valve.)

Anti-Ice System Schematic

Anti-ice Schematic (RR).

Wing Anti-Ice Test

An operational check of the valves can be conducted on the ground by pushing the Wing Anti-Ice Test Switch. The Test Switch signal bypasses the Wing Anti-Ice Switch and opens the valves if air pressure is available.

A timed delay automatically closes the valves to protect the wing structure from overheating. The VALVE Lights illuminate when the valves are open and extinguish when the valves close.