Anti-Ice and Rain

Question 1

With anti-ice switches in AUTO, what determines icing conditions?

Answer 1

2 icing condition detectors located on each side of the lower forward fuselage measure liquid water content

They are inhibited on the ground below 75 kts

Question 2

Are the icing detectors heated?

Answer 2

Yes, after engine start.

Question 3

Types of engine anti-ice?

Answer 3

Engine core and cowl inlet protection

Question 4

ICING ENG EICAS message?

Answer 4

Message and aural warning will sound of ice is detected and the ENGINE ANTI-ICE selector is OFF

Question 5

Green EAI indication?

Answer 5

Displayed above the N1 indication when an engine anti-ice valve is open

Question 6

Engine anti-ice duct leak?

Answer 6

Each engine has an anti-ice duct leak detection system. If leak is detected, the respective engine anti-ice valves will close

Question 7

Wing Anti-Ice?

How is it powered?

Locations?

Shedding?

Inhibited when?

Answer 7

An electric system powering thermal mats on 4 mid-wing slats on each wing. Slats 2-5 and 8-11

Each slat has three mats.

Wing anti-ice may be shed during high electrical loads (such as flap retraction) for as much as 30 seconds

Inhibited on the ground below 75 knots

Question 8

What protection is there against assymetrical wing icing

Answer 8

If one mat fails on a wing, the corresponding mat on the opposite wing depowers

Question 9

What is the logic for the wing anti-ice in AUTO?

What is meant by “clean up cycle?”

Answer 9

In flight, with the WING ANTI-ICE selector in AUTO, system is powered on and off by the ice protection system. Available in flight and above 75 kts on the ground.

After icing is no longer present, the system may enter a clean up mode. In the cleanup mode, the system continues to provide electrical power to the mats to clear any residual ice.

Question 10

WING ANTI-ICE selector in ON position?

Answer 10

Wing anti-ice will remain powered inflight as long as TAT is below 25 degrees C

Question 11

What is the anti-ice stick shaker logic?

When does stick shaker return to normal?

Answer 11

If flaps not up, either engine or wing anti-ice increases the stick shaker and minimum maneuvering speeds.

Stick shaker returns to normal when no icing conditions have been detected for a certain time and TAT is greater than 10 degrees C, or when aircraft lands

Question 12

How does the pack inlet anti-ice system function?

Answer 12

Pack inlets have electric heaters on the leading edge of each inlet.

Functions automatically with signals from the automatic ice detection system.

The anti-ice functions are inhibited on the ground and when the TAT is above 10 degrees

Question 13

How are flight deck windows heated?

Answer 13

Forward windows have exterior surface anti-icing protection and interior surface anti-fogging.

The side windows have interior surface anti-fogging protection only.

Question 14

What does INOP mean on the PRIMARY window heat switches?

Answer 14

Switch is not selected ON

Overheat is detected

System fault has occurred

Question 15

What are the BACKUP WINDOW HEAR switches for?

Answer 15

Backup anti-fogging system for the FWD windows.

Commanded on when the BACKUP L FWD and BACKUP R FWD switches are ON and the primary window hear system has failed

Question 16

When are probes heated?

Answer 16

3 pitot probes and 2 AOA vanes are heated when either engine is running

The TAT probe is heated in flight

Question 17

ENGINE ANTI-ICE switch in AUTO:

Answer 17

If icing conditions are detected,

the engine anti-ice valves will open and bleed air is supplied to the engine core and inlet cowl

when ice is no longer detected, the engine anti-ice valves close

automatic operation of the engine anti-ice system is inhibited on the ground

Question 18

ENGINE ANTI-ICE during ground operations?

Answer 18

ENGINE ANTI-ICE must be in ON position for ground operations, when OAT is 10 degrees or less and icing conditions exist

Question 19

EEC role in engine anti-icing?

Answer 19

In addition to bleed air protection, the EEC automatically adjusts engine idle speed to prevent engine icing and helps mitigate adverse effects when ice crystal conditions persist

Question 20

Inflight ENGINE ANTI-ICE procedures?

Answer 20

Must in AUTO or ON when

TAT is 10 degrees or less and icing conditions exist,
except during climb, cruise and descent when OAT is blow -40 degrees C

Question 21

When do engine anti-ice valves close automatically?

Answer 21

During engine start

Bleed air over temperature

Bleed air over pressure

Bleed air leak detected

Engine fire handle is pulled

Question 22

WING ANTI-ICE switch in AUTO?

Answer 22

Inflight, power is supplied when icing conditions are detected

When icing conditions are no longer present, the system may enter clean up mode, and WAI will remain on EICAS until this cycle is complete