Ice and Rain

Question 1

WAI
• Bleed air, piccolo tubes
• Electrically controlled, pneumatically actuated pressure control valve
• Spring loaded closed
• 130F
• Cross-over duct – redundancy
• Under/over temp switch
• Inhibited from takeoff to 1500 RA and above 35k ft
• If AUTO ON below 35k ft, it will stay ON above 35k ft until ice no longer detected
• If AUTO ON, do not manually select to ON
• Does not heat wheel well

Answer 1

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Question 2

WAI
• Bleed air, piccolo tubes
• Electrically controlled, pneumatically actuated pressure control valve
• Spring loaded closed
• 130F
• Cross-over duct – redundancy
• Under/over temp switch
• Inhibited from takeoff to 1500 RA and above 35k ft
• If AUTO ON below 35k ft, it will stay ON above 35k ft until ice no longer detected
• If AUTO ON, do not manually select to ON
• Does not heat wheel well

Answer 2

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Question 3

Engine AI
• High press bleed, piccolo tubes
• Electrically controlled, pneumatically operated thermal AI (TAI) valve
• Fail open (Powered close)

Answer 3

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Question 4

• Pre-cooler – 450 degF (400 wihout AI)

* Single bleed – 500 degF limit to 26,000ft (extract too much bleed air affect engine performance)

Answer 4

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Question 5

Windshield heat
• Electrical heating film to Main windshield and side windows
• HI/LO selects heated area (does not change set temperature)

Answer 5

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Question 6

Probe AI
•  3 x pitot
•  2x AOA
•  1 x TAT
•  7 x static port (not heated)
•  AUTO – WOW switch
•  OVRD – ON on ground

Answer 6

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Question 7

Ice detect
• 0.02 inches of ice
• Once ice detected, latched for 60 secs
• Heater on to remove ice from detector

Answer 7

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Question 8

• Ice shedding (QRH NI)

• Icing Conditions - <10 SAT/TAT visible moisture
• Standing water = icing conditions (Engine AI ON)
• Freezing rain – climb, warm air above
• Freezing Fog (< 0 degC, 1000m) (NI)
• Windshield heat (100-110 degC)
• HI same temperature – heast 2nd wire grid, more concentrated

• Will it affect Type IV fluid? Not if < 20 mins

Answer 8

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Question 9

• Ice shedding (QRH NI)

• Icing Conditions - <10 SAT/TAT visible moisture
• Standing water = icing conditions (Engine AI ON)
• Freezing rain – climb, warm air above
• Freezing Fog (< 0 degC, 1000m) (NI)
• Windshield heat (100-110 degC)
• HI same temperature – heast 2nd wire grid, more concentrated

• Will it affect Type IV fluid? Not if < 20 mins

Answer 9

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Question 10

LIMITATIONS
• Use of WAI above +10 or below -40 not recommended
• Use of WAI above 26k ft on single bleed prohibited
• Do not operate WAI on TOGA unless already at 130 degF
• Probe heat OVRD on ground >30secs prohibited
• EAI required for taxi if <10degC and visible moisture
• Use of flaps in icing restricted to takeoff, approach and landing
• Holding in icing at flaps 0 only

Answer 10

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