B737 NG

Anti‐Ice & Rain

IntroductionThermal anti-icing (TAI), electrical anti-icing, and windshield wipers are the systems provided for ice and rain protection.The anti-ice and rain systems include:

Anti-Ice Components Diagram[Option - Ice detector probe]

• Flight Deck Window Heat• Windshield Wipers• Probe and Sensor Heat

• Engine Anti-Ice System• Wing Anti-Ice System• Ice Detection System [Option]

(2 PLACES)ALPHA VANES

TEMPERATURE PROBEENGINE

ELEVATOR PITOT PROBES (2 PLACES)

COWL LIPICE DETECTOR PROBE

LEADING EDGESLAT

FLIGHT DECK

WINDOW HEATWINDSHIELD

WINDOWS

WIPERS

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Flight Deck Window Heat[Option – Window # 3 not heated]Flight deck window numbers 1, 2, 4 and 5 consist of glass panes laminated to each side of a vinyl core. Flight deck window number 4 has an additional vinyl layer and acrylic sheet laminated to the inside surface. Flight deck window number 3 consists of two acrylic panes separated by an air space.

[Option – Window # 3 not heated]A conductive coating on the outer glass pane of window numbers 1 and 2 permits electrical heating to prevent ice build–up and fogging. A conductive coating on the inner glass pane of window numbers 4 and 5 permits electrical heating to prevent fogging. Window number 3 is not electrically heated.

[Option – Window # 3 heated]Flight deck windows consist of glass panes laminated to each side of a vinyl core. Flight deck window number 4 has an additional vinyl layer and acrylic sheet laminated to the inside surface.

[Option – Window # 3 heated]A conductive coating on the outer glass pane of window numbers 1 and 2 permits electrical heating to prevent ice build–up and fogging. A conductive coating on the inner glass pane of window numbers 3, 4 and 5 permits electrical heating to prevent fogging.

Flight Deck Window Heat Operation[Option – Window # 3 not heated]The FWD WINDOW HEAT switches control heat to window No. 1. The SIDE WINDOW HEAT switches control heat to window number 2, 4, and 5.

[Option – Window # 3 not heated]Temperature controllers maintain window numbers 1 and 2 at the correct temperature to ensure maximum strength of the windows in the event of bird impact. Power to window numbers 1 and 2 is automatically removed if an overheat condition is detected. A thermal switch located on window 5 opens and closes to maintain the correct temperature of window numbers 4 and 5.

[Option – Window # 3 heated]The FWD WINDOW HEAT switches control heat to window number 1. The SIDE WINDOW HEAT switches control heat to window numbers 2, 3, 4 and 5.

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[Option – Window # 3 heated]Temperature controllers maintain windows numbers 1 and 2 at the correct temperature to ensure maximum strength of the windows in the event of bird impact. Power to window numbers 1 and 2 is automatically removed if an overheat condition is detected. Thermal switches, located on window numbers 3 and 5, open and close to maintain the correct temperature of window numbers 3, 4, and 5.

Flight Deck Window Heat Schematic[Option –Window # 3 heated and green ON lights]

ON

L WINDOW HEATOVHTSIDE

RFWD

ON

OFFOFF

ONON

FWD SIDE

PWR TEST

ON

OVERHEAT

L3 L2L1 R1

R2 R3

TEMPERATURECONTROLLER

CONDITION:WINDOW HEAT ONR SIDE OVERHEATED

SHIELDAIR

SHIELDAIR

FROMAIR CONDITIONING

SYSTEMWIND WIND

TEMPERATURECONTROLLER

TEMPCONT

TEMPCONT

THERMALSWITCH

L5L4

R5R4

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[Option –Window # 3 not heated and amber OFF lights]

Windshield WipersThe rain removal system for the forward windows consists of windshield wipers and a permanent rain repellent coating on the windows.

CAUTION: Windshield scratching will occur if the windshield wipers areoperated on a dry windshield.

L WINDOW HEATOVHTSIDE

RFWD

OFFOFF

ONON

FWD SIDE

PWR TEST

OFF

OVERHEAT

L3 L2L1 R1

R2 R3

TEMPERATURECONTROLLER

CONDITION:WINDOW HEAT ONR SIDE OVERHEATED

SHIELDAIR

SHIELDAIR

FROMAIR CONDITIONING

SYSTEMWIND WIND

TEMPERATURECONTROLLER

TEMPCONT

TEMPCONT

THERMALSWITCH

L5L4

R5R4

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Probe and Sensor Heat[Option - Captain’s pitot probe on standby power]Pitot probes, the total air temperature probe and the alpha vanes are electrically heated. Static ports are not heated. When operating on standby power, only the captain’s pitot probe is heated, however, the CAPT PITOT light does not illuminate for a failure.

Note: The pitot probe for standby airspeed is not heated when the airplane is on standby power.

Ice Detection System[Option]An advisory only ice detection system detects airplane icing in flight. The system consists of a probe located on the forward left fuselage and advisory lights located on the left forward panel.When the probe senses ice build–up inflight, the ICING light illuminates. When ice has previously been detected and the probe is no longer detecting ice, the ICING light will extinguish and the NO ICE light will illuminate. The ICING light and the NO ICE light do not illuminate simultaneously.

Note: Residual ice may remain on the window areas with the NO ICE light illuminated.

The ICE DETECTOR light, located on the forward overhead panel, will illuminate if the ice detection system fails. Illumination of the ICE DETECTOR light also illuminates the MASTER CAUTION and ANTI–ICE system annunciator lights.

Engine Anti–Ice SystemEngine bleed air thermal anti–icing prevents the formation of ice on the engine cowl lip. Engine anti–ice operation is controlled by individual ENG ANTI–ICE switches. The engine anti–ice system may be operated on the ground and in flight.

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Engine Anti–Ice System OperationEach cowl anti–ice valve is electrically controlled and pressure actuated. Positioning the ENG ANTI–ICE switches to ON:• allows engine bleed air to flow through the cowl anti–ice valve for cowl

lip anti–icing• sets stall warning logic for icing conditions.

Note: Stall warning logic adjusts stick shaker and minimum maneuver speed bars on the airspeed indicator. FMC displayed VREF is not adjusted automatically.

Note: Stall warning logic, airspeed indications, and minimum maneuver speeds on the airspeed indicator return to normal when engine anti–ice is positioned OFF if wing anti–ice has not been used in flight.

If the cowl anti–ice valve fails to move to the position indicated by the ENG ANTI–ICE switch, the COWL VALVE OPEN light remains illuminated bright blue and an amber TAI indication illuminates on the CDS after a short delay.The amber COWL ANTI–ICE light illuminates due to excessive pressure in the duct leading from the cowl anti–ice valve to the cowl lip.

COWL

ENGINE COWL

DUCT

9th

5th

ENGINEBLEEDVALVE

MODULATING &SHUTOFF VALVE

TOBLEED AIR

BLEED AIR

ANTI-ICE (TAI)

ANTI-ICEVALVE

1ON

OFF

COWL

COWL VALVE

ENGANTI-ICE

2

OPEN

COWLANTI-ICE ANTI-ICE

COWL VALVEOPEN

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Wing Anti–Ice SystemThe wing anti–ice system provides protection for the three inboard leading edge slats by using bleed air. The wing anti–ice system does not include the leading edge flaps or the outboard leading edge slats.The wing anti–ice control valves are AC motor–operated. With a valve open, bleed air flows to the three leading edge inboard slats, and is then exhausted overboard. The wing anti–ice system is effective with the slats in any position.

Wing Anti–Ice System OperationOn the ground, positioning the WING ANTI–ICE switch ON opens both control valves if thrust on both engines is below the setting for takeoff warning activation and the temperature inside both wing distribution ducts is less than the thermal switch activation temperature.Both valves close if either engine thrust is above the takeoff warning setting or either temperature sensor senses a duct overtemperature. The valves automatically reopen if thrust on both engines is reduced and both temperature sensors are cool.With the air/ground sensor in the ground mode and the WING ANTI–ICE switch ON, the switch remains in the ON position regardless of control valve position. The WING ANTI–ICE switch automatically trips OFF at lift–off when the air/ground sensor goes to the air mode.Positioning the WING ANTI–ICE switch to ON in flight: • opens both control valves• sets stall warning logic for icing conditions.

Note: Stall warning logic adjusts stick shaker and minimum maneuver speed bars on airspeed indications. FMC displayed VREF is not adjusted automatically.

Note: Stall warning logic remains set for icing conditions for the remainder of the flight, regardless of subsequent WING ANTI–ICE switch position.

Valve position is monitored by the blue VALVE OPEN lights. Duct temperature and thrust setting logic are disabled and have no affect on control valve operation in flight.

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Wing Anti–Ice System Schematic[Option - ICE DETECTOR light]

WING ANTI-ICEOFF

ON

L VALVEOPEN

R VALVEOPEN

ICEDETECTOR

THRUST

CONDITION:ON THE GROUNDWING ANTI-ICE ONENGINES AT IDLE THRUSTDUCT TEMPS LOW

BLEEDAIR DUCT

WING ANTI-ICECONTROL VALVE

THERMAL SWITCH GROUND

AIR

HIGHTEMPLOWTEMP

ABOVE T.O.WARNING

WARNINGBELOW T.O.

AIR-GROUND SAFETY SENSORS

BLEED AIR

LEVERS

LEADING EDGESLATS

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Window Heat Panel[Option – Green ON Lights]

[Option – Amber OFF Lights]

Window OVERHEAT LightsIlluminated (amber) – overheat condition is detected.

Note: OVERHEAT lights also illuminate if electrical power to window(s) is interrupted.

OVERHEAT

ON

L WINDOW HEATOVHTSIDE

RFWD

OVERHEAT

ON

OFFOFF

ONON

FWD SIDE

PWR TEST

OVERHEAT

ON

OVERHEAT

ON

FORWARD OVERHEAD PANEL

FORWARD OVERHEAD PANEL

OVERHEAT

OFF

L WINDOW HEATOVHTSIDE

RFWD

OVERHEAT

OFF

OFFOFF

ONON

FWD SIDE

PWR TEST

OVERHEAT

OFF

OVERHEAT

OFF

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Window Heat ON Lights

[Option – Green ON Lights]Illuminated (green) – window heat is being applied to selected window(s).Extinguished – • switch is OFF, or• an overheat is detected, or• a system failure has occurred• system is at correct temperature.

Window Heat OFF Lights

[Option – Amber OFF Lights]Illuminated (amber) – • switch is OFF, or• an overheat is detected, or• a system failure has occurred• system is at correct temperature.

Extinguished – window heat is being applied to selected window(s).

WINDOW HEAT SwitchesON – window heat is applied to selected window(s).OFF – window heat not in use.

WINDOW HEAT Test Switch (spring–loaded to neutral)OVHT – simulates an overheat condition.PWR TEST – provides a confidence test.

Note: Refer to Supplementary Normal Procedures for Window Heat Test procedures.

Windshield/Foot Air Controls

WINDAIRFOOT

AIRSHIELD AIR

FOOTWIND

AIRSHIELD

BELOW CAPTAIN’SINST PANEL

BELOW F/O’SINST PANEL

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FOOT AIR ControlsPULL – supplies conditioned air to pilots’ leg positions.

WINDSHIELD AIR ControlsPULL – supplies conditioned air to number 1 windows for defogging.

Windshield Wiper Selector Panel

Windshield WIPER SelectorsPARK – turns off wiper motors and stows wiper blades.INT – seven second intermittent operation.LOW – low speed operation.HIGH – high speed operation.

Probe Heat Panel[Option - Aspirated TAT]

FORWARD OVERHEAD PANEL

PARKINT

LOW

HIGH

L WIPERPARK

INT

LOW

HIGH

R WIPER

CAPT

TEMP

PITOT

VANER ALPHA

PITOT

R ELEVPITOT

PITOTF/O

HEAT

BPROBE

A

ON

OFF

VANEL ALPHA

PROBE

PITOTL ELEV

AUXTAT TEST

FORWARD OVERHEAD PANEL

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Probe Heat LightsIlluminated (amber) – related probe not heated.

Note: If operating on standby power, probe heat lights do not indicate system status.

PROBE HEAT SwitchesON – power is supplied to heat related system.OFF – power off.

TAT TEST Switch

[Option - Aspirated TAT]Push - Electrical power applied to TEMP PROBE on the ground.

Engine Anti–Ice Panel

COWL ANTI–ICE Lights Illuminated (amber) – indicates an overpressure condition in duct downstream of engine cowl anti–ice valve.

COWL VALVE OPEN LightsIlluminated (blue) –• bright – related cowl anti–ice valve is in transit, or, cowl anti–ice valve

position disagrees with related ENGINE ANTI–ICE switch position• dim – related cowl anti–ice valve is open (switch ON).

Extinguished – related cowl anti–ice valve is closed (switch OFF).

1ON

OFF

COWL

COWL VALVE

ENGANTI-ICE

2

OPEN

COWLANTI-ICE ANTI-ICE

COWL VALVEOPEN

FORWARD OVERHEAD PANEL

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ENGINE ANTI–ICE SwitchesON – • related engine anti–ice valve is open• stick shaker logic is set for icing conditions.

OFF – • related engine anti–ice valve is closed• stick shaker logic returns to normal if wing anti–ice has not been used in

flight.

Thermal Anti–Ice Indication

Thermal Anti–Ice IndicationsIlluminated – • Green – cowl anti–ice valve(s) open• Amber – cowl anti–ice valve is not in position indicated by related engine

anti–ice switch.

87.7 87.7

N1

TAITAI

86 4

10

20

86 4

10

20

UPPER DISPLAY UNIT

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Wing Anti–Ice Panel[Option - ICE DETECTOR System]

Wing Anti–Ice VALVE OPEN LightsIlluminated (blue) –• bright – related wing anti–ice control valve is in transit, or, related wing

anti–ice control valve position disagrees with WING ANTI–ICE switch position

• dim – related wing anti–ice control valve is open (switch ON).Extinguished – related wing anti–ice control valve is closed (switch OFF).

WING ANTI–ICE SwitchOFF – wing anti–ice control valves are closed.ON (in the air) –• wing anti–ice control valves are open• stick shaker logic is set for icing conditions.

Note: Stick shaker logic remains set for icing conditions for the remainder of the flight, regardless of subsequent WING ANTI–ICE switch position.

ON (on the ground) – • wing anti–ice control valves open if thrust on both engines is below

takeoff warning setting and temperature inside both distribution ducts is below thermal switch activation temperature

• control valves close if either engine thrust is above takeoff warning setting or thermal switch is activated in either distribution duct. Switch remains ON

• switch trips OFF at lift–off.

WING ANTI-ICEOFF

ON

L VALVEOPEN

R VALVEOPEN

ICEDETECTOR

FORWARD OVERHEAD PANEL

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ICE DETECTOR Light

[Option - ICE DETECTOR System]Illuminated (amber) – Ice detector system has failed.

Icing Advisory Lights[Option - Icing Detector System]

ICING LightIlluminated (amber) –• ice detector is detecting ice• light is inhibited on the ground.

Press – extinguishes light, if illuminated.

NO ICE LightIlluminated (white) –• ice detector is not detecting ice, and the ice detector probe had previously

detected ice• light is inhibited on the ground.

Press – extinguishes light, if illuminated.

ICINGP-CANCEL

NO ICEP-CANCEL

LEFT FORWARD PANEL

LimitationsEngine TAI must be on when icing conditions exist or are anticipated, except during climb and cruise below -40°C SAT.

[Option - 737-600/-700/-800 without stiffened elevator tabs](PRR 38506 or Service Bulletin 737-55A1080)After any ground deicing/anti-icing of the horizontal stabilizer using Type II or Type IV fluids, airspeed must be limited to 270 KIAS until the crew has been informed that applicable maintenance procedures have been accomplished that would allow exceedance of 270 KIAS. Once the applicable maintenance procedures have been accomplished, exceeding 270 KIAS is permissible only until the next application of Type II or Type IV deicing/anti-icing fluids.

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