Anti-ice & Rain Flashcards
Which Flight Deck windows are heated?
L1, R1, L2, R2.
What happens if an overheat condition is detected in a heated window?
The controller will remove power to the
window if an overheat condition is detected. An overheat cannot be reset until the window cools sufficiently (approximately 2-5 minutes) and is reset by placing the respective WINDOW
HEAT switch to OFF, then ON. An OVERHEAT light(s) will also illuminate if electrical power to the window(s) is interrupted.
What does the Engine Anti-Ice System protect from icing? How is heat provided for engine anti-ice?
Engine bleed air thermal anti-icing prevents the formation of ice on the engine cowl lip.
Engine Anti-Ice System uses 5th and 9th stage engine bleed air off the respective engine.
How does Engine Anti-Ice affect stall speed and engine thrust?
Stall warning logic adjusts Stick Shaker and minimum maneuver speed bars on
the airspeed indicator.
Approach idle is selected with engine anti-ice selected ON for either engine or flaps in the landing configuration.
What does a COWL ANTI-ICE (amber) light indicate?
The COWL ANTI-ICE (amber) light illuminates due to EXCESSIVE PRESSURE (greater than 65 psi) in the duct leading from the Cowl Anti-Ice Valve to the cowl lip.
What does a COWL VALVE OPEN bright blue light indicate? Dim blue? What other indications of engine anti-ice are there?
The COWL VALVE OPEN (blue) light illuminates:
• bright blue when the related Cowl Anti-Ice Valve is in transit or disagrees with the ENG ANTI-ICE switch position
• dim blue when the valve is open with the switch ON
The light is extinguished when the valve is closed and the switch is OFF.
What does a green TAI (Thermal Anti-Ice) above the N1 readout indicate?
The TAI message will be:
• green when the switch is ON and the Anti-Ice Valve is open
What does an amber TAI (Thermal Anti-Ice) above the N1 readout indicate?
The TAI message will be:
• amber when the Cowl Anti-Ice Valve fails to move to the position selected by the ENG ANTI-ICE switch
What does the Wing Anti-Ice System protect from icing?
The 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 outermost leading edge slat on each wing.
What is the difference between a dim blue and bright blue Wing Anti-Ice VALVE OPEN light?
The WING ANTI-ICE VALVE OPEN (blue) lights illuminate:
• bright blue when the related Wing Anti-Ice Valve is in transit or valve position disagrees with WING ANTI-ICE switch position
• dim blue when the valve is open with the switch ON
The light is extinguished when the valve is closed and the switch is OFF.
What would cause the Wing Anti-Ice valves to close automatically if selected ON while on the ground?
Both valves automatically close if:
- either engine thrust lever is advanced to the takeoff power position, or
- either temperature sensor senses a duct over temperature
How does the Wing Anti-Ice system operate if selected ON for takeoff?
On 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 (125°C)
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.
How is aircraft stall protection logic affected when using Wing Anti-Ice?
Stall warning logic adjusts Stick Shaker and minimum maneuver speed bars on
airspeed indications. FMC displayed VREF is not adjusted automatically. Stall
warning logic remains set for icing conditions for the remainder of the flight,
regardless of subsequent WING ANTI-ICE switch position.
Which external probes, vanes, ports, antennas, etc. are electrically heated by the Probe Heat System?
CA Pitot, CA AUX Pitot, FO Pitot, FO AUX Pitot, L & R Elevator Pitot, L&R ALPHA Vane
With the PROBE HEAT switches in AUTO, under what conditions will heat be applied to the probes?
PROBE HEAT switches, when positioned to AUTO, automatically apply electrical current to heat the probes when either engine is operating.
