Cold WX Ops Flashcards
What Icing conditions is take off prohibited in?
- Moderate and / or heavy freezing rain
- Heavy Snow +SN, Ice pellets PL, Hail GS. If for any reason a pre take off check cannot determine if frozen contaminants are adhering and / or that fluid failure has occurred.
Explain how partial snow removal works on a runway?
- Cleared runway width may not be less than 30m
- runway may be cleared to width of less than 45m. This is not considered narrow unless limited by snowbanks.
When is a runway contaminated?
- Runway contaminated when more than 25% of one third of the runway length and width being used is covered with:
Fluid contaminant greater than 3mm.
- Dry snow, Wet snow
- Standing water, Slush
Hard contaminant - Compacted Snow, Ice and wet ice.
Limitation: Captain & TOGA.
Can frost be on the aeroplane?
Thin hoar frost is acceptable on the upper surface of fuselage, radome and engine exterior surfaces.
Surface features can be distinguished beneath it.
Underside of wing tank. Max layer of 3mm is acceptable.
What to do if dispatch landing perf cannot be satisfied at destination?
Still permitted to go, provided two alternates are designated.
Engine warm up times?
3min except for NEO which also needs oil temp above 19degrees C so might be longer.
What are the Ice Shedding procedures?
Using brakes and when 3 degrees or less.
CEO: 70% N1 for 30 seconds at intervals not greater than 30min. Do prior to take off.
In freezing rain, drizzle, fog or heavy snow, do this every 10 minutes.
NEO: 50% N1 for 5 seconds at intervals not greater than 60min. Do prior to take off.
Minimum speed with Ice Accretion?
Wing Anti Ice Operative:
Conf: Clean, 1, 2 or 3. = VLS +10
Conf: FUll VLS + 5
Wing anti Ice In-operative
VLS +10 / Green dot
How and when to record icing conditions in the tech log?
Use for info section.
If taxiing in icing conditions with OAT 3 degrees or less.
Record taxi in time and log taxi time since last shedding if appropriate.
What are the de-icing fluid colours?
Type 1 - Straw
Type II - Light Green
Type IV - Dark Green
Cold weather temp limit in flight?
-70 degrees. Descend to increase temp.
If ice or fluid (Type IV Thick stuff) on radome or flight deck windows, what do we do?
Use a diluted type 1 mixture to remove it.
When operating a CEO aircraft in certain icing conditions on the ground, there is an enhanced ice shedding engine run up procedure. In what conditions is this enhanced procedure applicable and what is the procedure?
Freezing rain, freezing drizzle, freezing fog or heavy snow
In addition to standard 30 minute run ups, every 10 minutes, momentary run up to 70% N1
When operating in icing conditions on the ground, what are the engine run up procedures?
CEO: Accelerate engines to approximately 70% N1 for 30 seconds at intervals not greater than 30 minutes
NEO: Accelerate engines to approximately 50% N1 for 5 seconds at intervals not greater than 60 minutes
For both engine types, engine acceleration should be performed just before takeoff.
In event of frost formation on one or several areas of the wing, can localised deicing be applied to only the affected areas?
Yes Ensure both wings receive symmetrical treatment even if frost formation does not affect both wings symmetrically
A thin layer of frost is permitted on the airframe in a specific area. What area is this and what is the maximum permitted depth?
Underside wing tank areas
3mm
Additionally thin hoar frost permitted on upper fuselage, radome, engine exterior
In the three following scenarios, what is the minimum airspeed with ice accretion (defined by ice on the visual indicator)
1) Wing anti ice operative, CONF Clean, 1, 2 or 3;
2) Wing anti ice operative, CONF Full;
3) Wing anti ice not operative, all CONF
1) VLS + 10kt
2) VLS + 5kt
3) VLS + 10kt/GREEN DOT
What’s the definition of active frost?
A condition when frost is forming and occurs when Aeroplane Surface Temperature is less than or equal to 0°C AND less than or equal to the dew point
How should Probe/Window heat be operated when on the ground in cold weather?
ON during Prelim Cockpit Prep
AUTO after first engine start (heating continues automatically)
What do the colours in HOT signify?
Colours relate to snowfall intensity derived from Snowfall Intensities as a Function of Prevailing Visibility table
In a 2 step process when does HOT start?
Start of application of second fluid
What are the key points related to Local Wing Frost Removal
Must be done symmetrically
No precipitation falling
On request of pilot only
No HOT applicable. Clean Aircraft concept instead
Can you take off after HOT exceeded?
Yes, if pre-takeoff check conducted.
Pre take off check: failed fluid appears opaque; check both sides (wind affect one side more than the other); failure occurs leading/trailing edge first
Considerations for taxiing after landing in cold weather conditions
If chance of ice accumulating in flap area, leave flaps out
Leave engine anti ice on until shutdown
Perform engine run ups as required
SE taxi permitted if taxiway not slippery & no chance of ice accumulation on Engine #2
To retract flaps after engine shut down - procedure in Cold Weather Quick Reference
SNOWTAM max validity period
8 hours
Runway Condition Report RCR format
ICAO; DDMMTT; RWY; RWYCC; % per 1/3; Depth per 1/3; Surface descriptor per 1/3
EDDM 011209 08L 3/3/3 100/100/100 04/04/04 WET SNOW/WET SNOW/WET SNOW
What data do you use for contaminated runway performance? Take off, landing dispatch and landing in flight
Take off: Type & depth of contaminant, Runway Condition Determinator (Take Off)
Landing Dispatch: Type & depth of contaminant, Runway Condition Determinator (Landing Dispatch)
Landing In Flight: RCR and worst RWYCC contained in it. If non GRF format, use RCAM in QRH to get RWYCC
When do you make low altitude low temp corrections? What altitudes are they applied to?
Surface temp -10°C or below
DA & MDA
NPA minimum altitudes after passing FAF
FAF, except baro-VNAV procedures with temp limit
Contaminated Runway
A runway is contaminated when a significant portion of its surface is covered with: a layer of fluid contaminant not considered as thin OR a hard contaminant.
Significant portion: more than 25% of one third of runway surface area within the required length and width being used
What runway cold weather conditions do not permit takeoff?
Wet ice
Water on top of compacted snow
Snow over ice
RWYCC 0
Partial runway snow removal
Cleared/treated runway width - minimum 30m
Runways wider than 45m can be cleared to less than 45m. Not considered narrow runway unless limited by snow banks
What are the operational restrictions of operating on contaminated taxiways/runways?
No single engine taxi
No flex take off
Captains only take off
Consider:
Full length take off
Not tankering
