Anti-Ice, Rain

Question 1

What are the components of the rain removal system on the 737-800?

Answer 1

Windshield wipers and hydrophobic rain repellent coating on #1 windows
SEC 3.010, Page 7

Question 2

Which external probes, vanes, ports, antennas, etc. are electrically heated?

Answer 2

Anything that sticks out and has a light on the overhead
Heated anytime engine(s) are running (dark unless malfunction):
CAPT/FO PITOT
L/R ELEV PITOT
L/R ALPHA VANE
TEMP PROBE
AUX PITOT
We turn switch ON after start to match the condition (even though they’re
already hot - we cannot turn them off)
SH 3.010 pg 13

Question 3

Which Flight Deck windows are heated?

Answer 3

1 and #2 (both sides)

Question 4

For window heat, what causes the ON (green) lights and OVERHEAT (amber) lights to illuminate and
extinguish?

Answer 4

ON = power is being applied to the respective window.
The light will extinguish if:
- Overheat condition = OVERHEAT + MC/ANTI-ICE
- Switch turned OFF
- Failure in system

OVERHEAT = overheat condition for respective window (power is removed
automatically and cannot be reset until cooled) OR electrical power has been
interrupted.
The light will extinguish if overheat or power condition is corrected (if power is
removed, you must recycle switch to get power back)
SH 3.010 pg 3/4

Question 5

What does the Engine Anti-Ice System protect from icing?

Answer 5

The engine cowl lip.

SH 3.010 Page 7

Question 6

How is heat provided for engine anti-ice?

Answer 6

5th and 9th stage bleed air off the respective engine.
*if you close an engine bleed air valve you will still have anti-ice
Sec 3.010, Page 7

Question 7

How does the cowl anti ice system operate?

Answer 7

Controlled by ENG ANTI-ICE switches, ON or OFF on the ground and in flight in
icing conditions (+10 TAT to -40 SAT with visible moisture, and/or visibility less
than 1sm)
FMC and EEC monitor the status of the switches.
Section 3.010, Page 7

Question 8

What is the logic associated with ENG ANT-ICE positioned to ON?

Answer 8

• COWL VALVE OPEN - Cowl anti-ice valve opens
• TAI displayed above N1 indication (EECs command approach idle)
• Sets stall warning (stick shaker) for icing conditions (only while switch is ON, this is UNLIKE the wing anti ice!)

SH 3.010, pg 8

Question 9

What does a COWL ANTI-ICE (amber) light indicate?

Answer 9

Overpressure within the cowl lip
The ANTI-ICE annunciator and MASTER CAUTION lights will also illuminate.
SH 3.010 pg 8

Question 10

When does amber COWL ANTI-ICE light illuminate/extinguish?

Answer 10

COWL ANTI-ICE = overpressure (greater than 65 psi) in the duct leading from
the Cowl Anti-Ice Valve to the cowl lip.
Extinguishes when condition no longer exists/valve is closed?
SH 3.010 pg 8

Question 11

What does a COWL VALVE OPEN bright blue light indicate? Dim blue? Extinguished?

Answer 11

COWL VALVE OPEN Bright Blue= the valve is in transit or disagrees with the ENG ANTI-ICE
switch position

COWL VALVE OPEN dim blue = the valve is open with the ENG ANTI-ICE switch ON

The light is extinguished when the valve is closed and the switch is OFF
SH 3.010 pg 8

Question 12

What does an amber TAI indication above the engine N1 gauge mean? A green TAI?

Answer 12

Amber TAI = the valve fails to move to the position selected by the ENG ANTI-ICE
switch
Green TAI = the valve is open with the ENG ANTI-ICE switch ON

With TAI on, the EEC changes flight idle to approach idle
SH 3.010 pg 9

Question 13

What does the Wing Anti-Ice System protect from icing?

Answer 13

3 inboard slats only

SH 3.010 pg 10

Question 14

How is heat provided for wing anti-ice?

Answer 14

Bleed air

SH 3.010 pg 10

Question 15

How does the wing anti-ice system operate?

Answer 15

The WING ANTI-ICE switch controls the wing anti-ice control valve
Valve open = bleed air flows to slats then is exhausted overboard
SH 3.010 pg 10

Question 16

What is the logic associated with WING ANT-ICE positioned to ON? Off?

Answer 16

Stall speed increased for the rest of the flight

On the ground (shouldn’t be used on ground anyways):
Will automatically sit shut off for overheat or thrust lever advancement beyond 53 TLA. switch moves to off position at liftoff.

Question 17

How is wing anti-ice operation/logic different for ground ops vs in-flight?

Answer 17

On ground:

Valves close IF:
- Either engine thrust is above config warning position (53 degrees)

-An overheat

Valves automatically reopen if thrust is reduced and duct temp cools. (will not affect switch position)

-If switch is ON at lift-off, switch will automatically trip to the OFF position.

In flight: duct temperature and thrust setting logic are disabled and have no effect on control valve operation in flight.

Stall protection speeds for rest of flight
SH 3.010 P 12

Question 18

What does a Wing Anti-Ice L or R VALVE OPEN
bright blue light indicate?
Dim blue?
Extinguished?

Answer 18

BRIGHT: L/R VALVE OPEN = in transit or disagree
DIM: L/R VALVE OPEN = switch on (valve agrees with switch)
EXTINGUISHED: Switch off (valve agrees with switch)

Question 19

With the PROBE HEAT switches in AUTO, under what conditions will heat be applied to
probes?

Answer 19

Automatically applied after first engine start

Question 20

What do CAPT PITOT, L/R ELEV PITOT, L/R ALPHA VANE, TEMP PROBE, and AUX PITOT
amber lights indicate?
When do they illuminate/extinguish?

Answer 20

Electrical power not provided to prospective sensor

Illuminate with a fault/failure, extinguish when operating normally