Wing Anti Ice
Bleed air from the Pneumatic Manifold supplies air for 3
inboard leading edge slats on both wings in any position, both in-flight and on
the ground.
(B737NG has (on each wing) 2 krueger flaps inboard of the engine and 4 slats outboard of the engine)
Once (in flt) wing anti-ice is selected, stick shaker
logic will be set to 'ice'. Normally the stick shaker would start when IAS
approaches Vs by 7%, in 'ice' it will start at a value which is 10kts higher.
Even when switching wing anti-ice back to OFF (in flight) the stickshaker logic will remain in 'ICE' for the remainder of the flight. This is because the wing area between engines & fuselage is very sensitive to ice-development which you can not remove in flight.
To prevent the stickshaker logic to go in 'ICE' mode directly after takeoff when WING ANTI-ICE was selected on the ground, the switch will go to the OFF position automatically during rotation. This way, you as the pilot, are in control of the stickshaker logic.
**VREF
will NOT be AUTOMATICALLY adjusted to the 'ice' stickshaker value. You must
calculate the new value and then insert this manually into the FMS.
**Wing anti-ice control valves will close on the ground if thrust is above T/O warning setting. The valves will re-open if thrust is reduced again.
**ground overheat thermal switches will close BOTH wing anti-ice valves if EITHER OF THE 2 senses an OVERHEAT condition.
**APU BLEED AIR for wing anti ice is NOT allowed.
#For all types of bleed air --> Valves are ELECTRICALLY controlled
& PNEUMATICALLY operated.
**Wing anti-ice control valves will close on the ground if thrust is above T/O warning setting. The valves will re-open if thrust is reduced again.
**ground overheat thermal switches will close BOTH wing anti-ice valves if EITHER OF THE 2 senses an OVERHEAT condition.
**APU BLEED AIR for wing anti ice is NOT allowed.
