Icing Flashcards
1
Q
What are the two main types of icing?
A
- Airframe
- Engine
2
Q
What conditions are required for ice to form?
A
- Visible moisture
- Temp +10 to – 40°C
- Airframe must be <0°C
3
Q
What is the freezing level?
A
The altitude at which the temperature is 0°C
4
Q
Do snow an ice crystals in flight typically adhere to an aircraft?
A
No
5
Q
Where is the worst icing found?
A
- Near the Freezing Level
- Heavily stratified clouds (St, Ns)
- Cumulus or Cumulonimbus clouds with strong updraughts
- In freezing rain beneath a NS
6
Q
What are the types of airframe ice?
A
- Clear
- Rime
- Mixed (Clear and Rime)
- Frost
7
Q
Elements of clear ice?
A
- Most dangerous of all
- Hard to see
- Tenacious
- Heavy
- Smooth
- Can flow back over wing
- Caused by super-cooled water droplets freezing on contact.
- Latent heat released as water freezes delays freezing and allows water to spread
8
Q
Elements of Rime Ice
A
- Supercooled tiny droplets freeze on a surface <0°C
- Mixture of ice and air
- Rough, opaque, crystalline, brittle
- Can form between 0°C and -40°C
- Most common -10°C to -20°C
9
Q
Elements of mixed ice?
A
- Due to droplets of varying sizes
- Most common form of icing
10
Q
Where is pure rime ice most likely to occur?
A
High AS or AC
11
Q
Where is pure clear ice most likely to occur?
A
Freezing rain below NS
12
Q
Elements of Frost (Hoar)
A
- Occurs when moist air condenses on a freezing surface.
- A white crystalline coating that easily brushes away.
- Typical conditions:
—– Clear night
—– Calm wind
—– High humidity
13
Q
Dangers of frost?
A
- Separation of Laminar flow over wing
- Obscure vision
- Freeze controls
- Increase weight
14
Q
CU are predominantly liquid water droplets until __________
A
-23C
15
Q
At what temperatures is the highest risk of icing found in CU?
A
0°C to -15°C
