Ice Detection/Protection Flashcards
What is the purpose of the Engine Anti-Ice System?
The Engine Anti-Ice System provides anti-icing protection by controlling the respective valve.
Example: The reset valve begins to open for anti-icing protection.
How does the Wing Anti-Ice System function?
The Wing Anti-Ice System uses bleed air as a source to provide symmetrical ice protection throughout the flight.
Example: The system opens the bleed valve to ensure protection.
When do the engine and wing anti-ice systems operate automatically?
They operate automatically based on system logic when the mode selector is in AUTO.
What powers the Windshield Heating System?
The Windshield Heating System is electrically powered.
What happens to the windshield heat when only a single source of power is available?
On the ground, the windshield heat is OFF.
When is the Air Data Smart Probe (ADSP)/TAT Heating System ON?
The ADSP/TAT Heating System is ON when the engine is running and AC power is available with the probe heater switch on.
What is the purpose of the Water and Waste Ice Protection System?
Prevents fill drain nipples from freezing
How many ice detectors are installed on the aircraft?
There are two (2) ice detectors installed on the left and right side of the nose section.
What is the first step in the operation of the Ice Detectors?
Probes vibrate at a certain frequency
What happens when ice accumulates on the probes?
Vibrating frequency changes, causing the probes to heat up
What activates after the probes heat up?
Wing & Engine Anti-Ice activates, melting the ice off the probes
How long does the ice detection system remain active after icing conditions are no longer sensed?
It remains on for 5 minutes.
What happens in case of a dual ice detector failure?
The anti-ice operation is only possible in manual mode.
What should the MODE knob be set to under normal conditions?
The MODE knob should always be in AUTO unless directed to ON by the QRH.
What conditions allow for the ice detection system to be turned OFF?
When ice has been detected, the system can be turned OFF if:
- >1700’ AGL or 2 minutes after takeoff
- Engines running
- Wheel speed > 40 knots
Can the APU be used for deicing?
No, the APU cannot be used for deicing.
What sources are used for aircraft anti-icing and de-icing?
Bleed air heat and electric heat
What uses bleed air for ice protection?
Sourbo blind slats (slats 2, 3 and 4 on each wing)
What uses electric heat for ice protection?
Total air temperature (TAT) probes
If an engine fails, does the opposite wing and engine receive ice protection?
The failed engine does not receive ice protection
The wing does
How many ice detectors are required for icing detection?
One
How long will the de-icing system remain on after icing is no longer detected?
5 minutes
If REF A/l on the MCDU is set to ‘OFF’ and icing conditions are encountered during takeoff, will the de-icing system turn on?
Not until 1700 ft. or 2 minutes after takeoff (whichever happens first)
Can the APU be used to provide bleed air for anti-icing?
No
What is protected from ice & rain?
Engine inlets, probes, total air temperature probes, windshields, water & waste drain systems
Is the ice protection system automatic?
Yes, under normal conditions
Can the pilot override the automatic system?
Yes
How is ice detected in flight?
Using two ice detectors with a vibrating sensor element that changes frequency when ice builds up.
What stage is the bleed air valve for engine components?
6th stage (slats only)
How is bleed air directed for pneumatic anti-ice?
Engines (onside only), wings (onside priority, offside if bleed source failure)
What happens if there is a single bleed source failure?
The crossbleed automatically opens.
How should the MCDU be set if there are icing conditions present on the ground?
ENG ON - Between 5°C and 10°C with visible moisture
ALL ON - Below 5°C with visible moisture
What does selecting ‘ALL’ on the MCDU provide?
Engine anti-ice ON when engines are running
Wing anti-ice ON at 40 kts. wheel speed
If ‘ALL’ is selected on the ground, at what point will the anti-ice system become automatic?
1700’ AGL or 2 minutes after takeoff (whichever happens first)
If ‘OFF’ is selected on the ground, at what point will the anti-ice system become automatic?
1700’ AGL or 2 minutes after takeoff (whichever happens first)
How does the failure of one of the two power sources affect the windshield heating system?
On ground Inhibited
In Flight Left side is heated (right heats if left has failed)
What does the ‘TIMER’ selection on the windshield wiper switch do?
Activates the associated wiper in 8-second intervals
What happens if the wiper is operated on a dry windshield?
The wiper will stop
To reset wiper move switch to ‘OFF’
When do the smart probes heat?
When an engine is running
In flight; or
When the ADS probe heater button is pushed with AC power without engines running on the ground
Is there a test for the anti-ice system?
Yes, but maintenance performs this test
How should the aircraft be configured for de-icing?
Bleeds OFF
Packs OFF
Stab trim Full nose down
Flaps UP
Engines and APU ON or OFF
APU is recommended OFF. Use the De-icing/Anti-Icing Fluid Application Checklist
