11.12 Ice and Rain Protection

Question 1

What are the three most common types of ice encountered in flight?

Answer 1

Clear
Rime
Mixed

Question 2

What is clear ice also known as?

Answer 2

Glaze ice

Question 3

How does clear ice form?

Answer 3

Formed by larger supercooled water droplets, of which only a small portion freezes immediately.

Question 4

How is rime ice formed?

Answer 4

Small, supercooled water droplets, such as those in stratified clouds or light drizzle, freeze rapidly on contact with a sub-zero surface.

Question 5

What is mixed ice?

Answer 5

Mix of rime and clear.

Question 6

What are wing inspection lights for?

Answer 6

Detection of ice.

Question 7

What is a hot rod detector?

Answer 7

Similar to the ice rod on the front of the windscreen, it is found outside a flight deck window, is heated and lit.

Question 8

Where is the rotary ice detector mounted?

Answer 8

Forward fuse

Question 9

How does a rotary ice detector work?

Answer 9

When ice builds up it takes more rotational torque to shave off the ice with the blade from the rotary part.

Question 10

How does a vibrating ice probe detect ice?

Answer 10

It vibrates at a set frequency, as ice builds up the frequency decreases.

Question 11

How does a sangamo weston ice detector work?

Answer 11

It detects freezing temps and moisture separately to decide if there is a chance of ice build up.

Question 12

What three key parts does a sangamo weston ice detector have?

Answer 12

Moisture detector controller
Moisture Sensing Head
Thermal switch

Question 13

How does a Beta Particle Ice Detection Probe (Sunstrand System) work?

Answer 13

Beta particles are released, and reach a sensor, ice would reduce the amount of particles making it too the sensor.

Question 14

What is thermal pneumatic anti icing used for?

Answer 14

Leading edges

Question 15

In the wing anti icing system when does the temperature of the bleed air trigger the overheat warning?

Answer 15

100 °C outboard or 175 °C inboard

Question 16

How can a surface be anti iced?

Answer 16

Keep it dry
Keep it hot

Question 17

What does the WAI valve do?

Answer 17

Controls the flow of bleed air from the pneumatic system to the WAI ducts.

Question 18

In auto how long will the WAI valves stay open?

Answer 18

3 Mins

Question 19

If an aircraft has EAI (engine anti ice) is it activated before or after WAI?

Answer 19

Beforee

Question 20

What is weeping wing?

Answer 20

Chemical protection of the wing and stabiliser

Question 21

What is ice protection based upon?

Answer 21

Freezing point depressant concept

Question 22

What is the freezing point depressant concept?

Answer 22

An antifreeze solution is pumped from a reservoir through a mesh screen, embedded in the LEs of the wings and stabilisers.

Question 23

What does the TKS (weeping wing) system contain?

Answer 23

Laser drilled titanium panels with over 800 tiny holes.

Question 24

How long does the capacity of the TKS system reservoir allow?

Answer 24

1-2 hours of operation

Question 25

What are the most common component used for de icing wings on small aircraft?

Answer 25

Pneumatic boots

Question 26

How long are LE boots inflated for?

Answer 26

6-8 seconds

Question 27

When the de-icing boots are not in use what happens to them?

Answer 27

The vacuum suction keeps them tight to the aircraft.

Question 28

What PSI does the ice boots deflate at?

Answer 28

17 psi

Question 29

How can the life of the rubber boots be extended?

Answer 29

By storing the when they are not needed.

Question 30

How is grease and oil removed from the rubber boots?

Answer 30

Naphtha

Question 31

Where can chemical de-ice for windshields be found?

Answer 31

Small aircraft

Question 32

What happens in electrical propellor de-icing if the heat is enough to melt the ice but not evaporate the water?

Answer 32

Runback occurs, causing the melted ice to freeze on other parts of the blade.

Question 32

How is chemical de icing delivered to the propellors?

Answer 32

Slinger ring

Question 33

What systems do aircraft use to control rain on the windshield?

Answer 33

Chemical Pneumatic Coatings

Question 34

What is the rainboe system?

Answer 34

Rain repellent system used that has CFC 113

Question 35

Why is rain repellent now banned?

Answer 35

Because it contains CFC which is ozone depleting.

Question 36

When and why should rain repellent systems not be used?

Answer 36

Dry conditions, as heavy undiluted repellent restricts window visibility.

Question 37

Which treatment is a popular repellent?

Answer 37

Hydrophobic coating

Question 38

What should you not do to hydrophobic coatings?

Answer 38

Apply wax or polish

Question 39

What is the life of hydrophobic coating effected by?

Answer 39

Wiper blade tension

Question 40

What does each windshield wiper system consist of?

Answer 40

Wiper, wiper arm and wiper motor.

Question 41

What is the wiper blade tension?

Answer 41

Then angle at which the blade sweeps across the windshield.

Question 42

What does the off/park mode do to the wipers?

Answer 42

Sets it to the park/stowed mode.

Question 43

How many cycles are there in low mode for the wipers?

Answer 43

160 cycles per minute.

Question 44

How many cycles are there in high mode for the wipers?

Answer 44

250 cycles per minute