Ice & Rain Flashcards
What ice protection does pneumatic air provide?
- wing leading edges
- horizontal stabiliser leading edges
- engine air intakes
- gas paths
Where are the chordwise boots used?
Leading edges and gas paths
Where are the annular boots used?
Engine intakes
What happens when the boot is deflated?
It is held to the structure by Venturi effect
The Venturi effect is created by the bleed air
What controls the inflation of the boots?
The associated distribution valve
There are seven distribution valves
What uses electrical power for deicing?
- prop blades
- windshields
- probes
- static ports
- flight control horns
Where is the ice detector located?
Rosemont Ice detector probe - Under the left wing
Provides crew with visual and aural alert when ice is accreting on the probe
Powered by AC Wild bus 2
As ice accumulate the vibration freq changes
Where is the Ice Evidence Probe located?
Located outside and below the Captains left side window
Visible to both pilots and provides a visual indication of ice accretion
When will the amber icing light illuminate?
When 0.5 mm of ice has accumulated on the probe
Probe will initiate a heat cycle to remove accretion and start again
What does it mean if the ICING light extinguishes on its own?
Indicates that ice is no longer accumulating
Does not indicate that airframe is clear of residual ice
What is the delivery pressure of the de-ice valves?
20.3 psi
What distributes air to the wing and horizontal stabiliser distribution valves?
The common manifold
What controls the boots?
The associated MFC
How long is the boots inflation cycle?
If SAT is greater than -20 cycle is set at 60 secs with 20 sec dwell
If SAT is less than -20 cycle is set at 180 secs with 140 sec dwell
What happens if you press in the DE-ICE MODE SEL pb?
SLOW caption is the pb is illuminated and cycle is forced to 180 secs
What is electrically anti-iced?
- props
- flight control horns
- probes
- windshields
What anti-ices the flight control horns?
AC Wild electrical power
115 VAC
Horn anti-icing is inhibited on the ground
Why does the ICING AOA illuminate green when anti-icing is on?
The AOA threshold is lowered by selection of anti-ice
Serves as a reminder to the crew to set speed bugs and observe minimum icing speeds
Light can only be extinguished manually by pressing the pb after both horn anti-icing buttons have been selected OFF
What powers the propeller heat?
AC Wild bus
When is the low power propeller cycle used?
Between 0 and 10 degrees celcius
Heating time is 10 seconds
Normal cycle when the pb is in the out position
What is the high power propeller cycle?
Heating time is 20 secs and there is no pause between cycles
Why are the two front windshields heated?
To prevent anti-icing and defogging
The side windows are heated to prevent fogging only
What powers the windshield heat?
The associated AC Wild bus
What does the temperature controller maintain the windshields at?
Outside ply maintained at 2 degrees
Maintains inner ply above 21 degrees to prevent fogging
What heats the side windows?
Heated by the 28 VDC bus
Temp regulated to maintain the inner temp over 20 degrees
Why is the aft portion of the side windows not heated?
The heating element is designed to warm the whole plane
Ice build up aft of the heated portion is usually an indication of severe icing and/or freezing rain
What is the probe heat source?
AC power used to heat:
- pitot probes
- alpha probes
- TAT probe
How is static port heat controlled?
Static port heat controlled by the associated probe heat pb
What happens to TAT probe heat on the ground?
Automatically inhibited and the condition of the probe is not monitored
What is the windshield wiper speed limit?
160 kt
When does the ICING light illuminate?
When ice accretion is detected
It will be steady if both horn anti-icing and airframe de-icing are selected on
It will flash if either is off
What is the icing test?
Test button pressed and held for 3 seconds
During the test the ICING amber light flashes and a single chime will sound
FAULT will illuminate if a fault is detected during the test
When will the blue DEICING light flash?
If the de-icing system is still on 5 minutes after the last detection of ice accretion
When will the FAULT light on the airframe air bleed pb light?
If the pressure downstream of the de-ice valves is below 14 psi for more than 10 secs or when air temp of the bleed air exceeds 230 degrees
When will the airframe pb FAULT light illuminate?
When a distribution valve is commanded closed but bleed air pressure still exists downstream or if a valve is commanded open but no pressure is sensed
When does the MODE SEL AUTO FAULT light illuminate?
- failure of the 1B or 2B MFC
- ADC failure
What is the de-icing emergency mode?
- timing cycle of 60 secs
- OVRD caption illuminates white
- all de-icing lights extinguish
Used when a fault light illuminates
When will the FAULT light in the DEICING OVERRIDE pb illuminate?
If there is a failure in both MFC modules
What is level 1 anti-icing?
Must be selected on before each flight
Probe and forward windshield anti-ice are turned on
What is anti-icing level 1.5?
Take off in ground icing but flight into non-icing conditions
Continuous relight selected
Prop anti-ice selected on
What is anti-icing level 2?
Operating or taking off in icing conditions
- prop anti-ice
- horn anti-ice
- side window anti-ice
- engine de-ice
Continuous relight selected
What is anti-ice level 3?
Flight where ice is accreting
- prop heat
- horns and side window anti-ice
- engine de-icing
- airframe de-icing
Continuous relight selected
With the MOD SEL pb in AUTO, what system determines the de-icing cycle?
The MFCs and the ADCs
