Anti-ice Flashcards
When may the window heat power test be accomplished?
When any WINDOW HEAT Switch ON with its associated ON Light extinguished
Which windows are heated, and how are they controlled?
- L/R FWD Switch! associated No. 1 windows
* L/R SIDE Switch! associated No. 2 windows (and Nos. 4 & 5, if installed)
When is power supplied to the probe heat systems?
When the related Probe Heat Switch is ON. When the Probe Heat Switch is in the AUTO position (some aircraft), power is automatically supplied when either engine is running.
What is indicated by a COWL ANTI-ICE Light?
Overpressure in the duct downstream of the cowl anti-ice valve
How does engine or wing anti-ice affect stall warning logic?
Stall warning logic adjusts stick shaker (S/S) and min maneuver (M/M) speed bars on the airspeed indicator. FMC displayed VREF is unchanged. Stall warning logic resets when engine anti-ice turned off, unless wing anti-ice was used (resets upon landing).
What are the indications of a cowl valve which fails to go to the commanded position?
The COWL VALVE OPEN Light stays bright, and an amber TAI is illuminated above the related N1 indicator
What are the indications of a wing valve which fails to go to the commanded position?
The associated Wing Anti-Ice VALVE OPEN Light stays bright
What is the definition of icing conditions?
OAT (on ground and for takeoff), or TAT (in flight) is 10°C (50°F) or below, and visible moisture in any form is present (clouds, fog with visibility of one mile or less, rain, snow, sleet, ice crystals), or operation on ramps, taxiways, or runways where surface snow, ice, standing water, or slush may be ingested or freeze on the engines or nacelles.
When must engine anti-ice be used?
During all ground and flight operations when icing conditions exist or are anticipated, except during climb or cruise when the temperature is below -40°C SAT
When must wing anti-ice be used?
On the ground –
• Between engine start and takeoff, when icing conditions exist or are anticipated,
! unless the aircraft is, or will be protected by Type II or Type IV fluid
In flight –
• Primary method is to use as a de-icer, allowing ice to accumulate before turning wing anti-ice on
• Secondary method is to use as anti-icer only, using wing anti-ice prior to ice accumulation. This method is required during extended operations (including holding) in moderate to severe icing conditions.
If wing anti-ice required after takeoff, what is the minimum altitude for use?
1000’ AGL
What is the maximum altitude recommended for use of wing anti-ice?
FL350 – Use of wing anti-ice above this altitude may cause bleed trip off and possible loss of cabin pressure
When must the upper wing surfaces be visually inspected from the cabin prior to gate departure?
When Cold Soaked Fuel Frost (CSFF) is suspected, i.e. when
• a large amount of fuel remains in the wing tanks after landing
• frost/ice observed on lower wing surface outboard of fuel measuring stick #4
• fuel temp
During off gate deicing operations, which parts of the aircraft must be clear of frozen contamination prior to pushback?
Engine inlets
Which parts of the aircraft must be free of frozen contamination prior to engine start?
Engine inlet ducts, doors and probes, exhaust ducts, and thrust reversers. N1 fan must be free to rotate.
May hot water be used to remove frozen contamination on the engines prior to start?
No, but the contamination may be removed with limited amounts of heated deicing fluid.