ICE AND RAIN

Question 1

Is automatic ice detection available on the ground?

Answer 1

No, only in flight

Question 2

Is Engine anti-ice available during Engine out taxi?

Answer 2

Yes, but only on the operating Engine. No cross feed of air for Engine anti-ice

Question 3

Where is EAI indicated when in operation?

Answer 3

Next to N1 levels on primary EICAS display

Question 4

Is Wing anti-ice available on the ground?

Answer 4

No

Question 5

List the inhibits for wing anti-ice

Answer 5

• No WAI on gnd.
• Inhibited for 5 min after liftoff if TAT is +10 deg or more regardless of switch position (ON or AUTO)
• AUTO inhibited for 10 min with T/O thrust or until the engines comes out of THR REF to CLB.

Question 6

Where is wing anti-ice indicated during operation?

Answer 6

Between N1 and EGT indications on primary EICAS

Question 7

Is wing anti-ice available for the other wing after one wing anti-ice valve fails closed?

Answer 7

No, the other valve closes to prevent assymetric ice pick-up

Question 8

Which windows have anti-ice protection?

Answer 8

The 2 main FWD windows

Question 9

How many wiper speeds are there and what are the cycles/min for each one of them?

Answer 9

3
INT: 1 cycle every 7 seconds
LOW: 160 cycles/min
HIGH: 250 cycles/min

Question 10

Are the pitot and TAT probes constantly heated?

Answer 10

No
Pitot: When either engine is running
TAT: In flight

Question 11

How many pitot probes are there?

Answer 11

3

Question 12

How many Angle Of Attack (AOA) probes are there and how are they heated?

Answer 12

2

They are electrically heated

Question 13

How many ice detectors are there on the B777?

Answer 13

2

Question 14

What is the general principle of operation of the ice detectors?

Answer 14

They vibrate at approx 40’000 Hz and ice formation will make them vibrate at a lower frequency. Below a certain frequency (39’867Hz) the heater turns on and melts the ice. Should take about 5-7 seconds to melt the ice. If heater is on for more than 25 sec it is turned off and a fault condition is registered.
The detector has control logic that counts the number of heating cycles.

Question 15

How many heating cycles is needed to start EAI?

Answer 15

2 cycles

Question 16

How many heating cycles is needed to start the WAI?

Answer 16

10 cycles

Question 17

How long will the ice detector system function after it has been starting sending signals to the ACIPS (Airfoil and Cowl Ice Protection System)?

Answer 17

Signal will be on until

• No ice is detected for 3 min
• The airplane is on the ground
• The heater is on for more than 15 sec

Question 18

How many slats per wing are heated by wing anti-ice?

Answer 18

3 per wing
Left wing: 3,4,5
Right wing: 10, 11, 12

Question 19

What can be a visual indication of light icing?

Answer 19

Under the windshield wipers is one of the first places where icing will form. Precipitation falls on the bottom of the windshield and runs up the wipers.

Question 20

What can be a visual indication of moderate icing and possibly airframe icing?

Answer 20

If it forms on the protruding parts of the windshield wipers that is a good indication that icing is probably present on other parts of the airframe

Question 21

What can be a visual indication of severe icing?

Answer 21

If ice forms on a flat heated windshield that indicates severe icing.

Question 22

What does the EICAS message “ICE DETECTORS” mean and what is your action?

Answer 22

EICAS “ICE DETECTORS” advisory message means that automatic ice detection and alerting has failed. Set Anti-ice switches to ON to ensure proper anti-icing functionality in icing conditions.