ANTI-ICE PANEL

Question 1

L/R VALVE OPEN Lights

Answer 1

Illuminated (blue):

• BRIGHT: wing AI control valve IN TRANSIT or DISAGREEMENT with switch position
• DIM: Switch is ON and AI control valve is OPEN (normal with WAI operating)

Extinguished:

• Switch is OFF and AI control valve is CLOSED (normal)

Question 2

WING ANTI-ICE Switch

what can we expect to see during the takeoff roll if we taxi with the wing anti ice on? (1sp)

Answer 2

[1sp. once you hit toga and the throttles are advanced, the valve will close automatically. once the valve is closed and switch is in the ‘ON’ position, the light will go bright. When we take off the switch works with the air/ground sensor - the switch trips OFF and the light goes out.

OFF:

• wing AI control valves are CLOSED (valve open lights are OUT)

ON: (GROUND)

• wing AI control valves OPEN IF:
  
  • Thrust on BOTH engines below takeoff warning setting AND
  • Temp inside BOTH distribution ducts is below thermal switch activation temp
• wing AI control valves CLOSE IF:
  
  • EITHER engine thrust is above takeoff warning setting OR
  • Thermal switch is activated in EITHER duct (switch stays ON)
• switch trips OFF at lift off

ON: (AIR)

• wing AI control valves are OPEN
• stick shaker logic is set for icing conditions (if WAI is turned on it will stay there for rest of flight no matter what the position of the switch is)
• FMC Vref is NOT automatically adjusted
• *** use of WAI > FL 350 may cause a DUAL BLEED trip and possible loss of cabin pressure

Question 3

COWL ANTI-ICE Lights

What does this light ‘on’ mean? (1sp)

Answer 3

[1sp - excessive pneumatic pressure ONLY]

Illuminated (Amber): indicates an OVERPRESSURE in duct downstream of engine cowl AI valve

Question 4

COWL VALVE OPEN Light

Answer 4

Illuminated (blue):

• BRIGHT: Cowl AI Valve in transit or disagreement with ENG AI switch position
• DIM: switch is ON and the related cowl AI valve is OPEN

Extinguished:

• related cowl AI valve is CLOSED (switch OFF)

Question 5

ENG ANTI-ICE Switches

Answer 5

ON:

• OPENS the related AI valve (illuminates COWL VALVE OPEN light)
• stick shaker logic is set for icing conditions

OFF:

• related AI valve is CLOSED (COWL VALVE OPEN LIGHT goes out)
• stick shaker logic returns to NORMAL if WING AI has NOT been used in flight
• also get a TAI indication on the N1 indicator (amber or green)