The supplemental ground wing anti-ice system provides a limited amount of bleed air to the wing leading edge, when the aircraft is on the ground, to maintain an ice-free leading edge by maintaining a surface temperature between 70°F (21°C) and 88°F (31°C).
The system is automatically activated when all of the following conditions are met:
• The aircraft is on the ground
• Both thrust levers are at, or near, the idle position
• The thrust reversers are stowed
• Both ANTI-ICE–COWL switches are selected ON
• The SYS (OFF) switch on the SUPP GND WING ANTI-ICE panel is not pressed in