Ice Protection/Detection Flashcards
What sources are used for aircraft anti-icing and de-icing?
● Bleed air heat
● Electric heat
What uses bleed air for ice protection?
● Engine lips
● 3 outboard slats (slats 2, 3 and 4 on each wing)
What uses electric heat for ice protection?
● Smart probes
● Total Air Temperature (TAT) probes
● Windshields
● Water lines
● Pressurization static port
If an engine fails does the opposite wing and engine receive ice protection?
● Yes for the wings. The crossbleed valve opens to provide symmetrical ice protection for both wings
● The failed engine does not receive heat to the engine cowl
How many ice detectors must be working to have icing detection?
One. There are two for redundancy
How long will the de-icing system remain on after icing is no longer detected?
5 minutes
If REF A/I on the MCDU is set to ‘OFF’ and on takeoff roll icing conditions are encountered, 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
Wing leading edge
Smart probes and 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?
2 ice detectors
Vibrating sensor element that changes frequency when ice builds up around it
Once ice is detected, the sensor element heats, the ice melts, the normal vibrating characteristics are restored, and the heating process stops. The cycle repeats as ice rebuilds on the probes
What compressor stage is bleed air tapped for anti-icing operations?
10th High Stage Valve (HSV) (engine cowls and/or slats)
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
NOTE: APU is recommended OFF. Use he Dicing/Anti-Icing Fluid Application Checklist
