Icing

Question 1

Threat error management.

Answer 1

Reduced aerodynamic performance.
Restricts controls.
Reduces visibility.
Increases stall speed.
Instrument errors.

Question 2

How do SCWD start to freeze?

Answer 2

When a disturbance occurs (contacts aircraft).

Question 3

What is the temperature range that water droplets can remain supercooled?

Answer 3

0 degrees to -40 degrees.

Question 4

How does the size of SCWD vary through the temperature range?

Answer 4

Smaller at colder temperatures.
Larger closer to 0.

Question 5

At what temperature does Rime/Clear ice form?

Answer 5

Clear ice 0,-15 degrees.
Rime ice colder than -15degrees.

Question 6

what is the process of Large SCWD freezing? / How does clear ice form?

Answer 6

SCWD contacts the leading edge.
Some freezes and creates hard,clear ice which gives off latent heat.
Some liquid parts flow back towards trailing edge.

Question 7

How does the thickness of the wing affect icing?

Answer 7

Greater ice accretion of a thinner wing.
This is because a large wing pushes the moisture and air away from the wing, while a thing wing doesn’t push as much away.

Question 8

What are the types of airframe ice?

Answer 8

Clear ice
Rime ice
Mixed ice
Hoar frost

Question 9

How do snow and hail affect and aircraft in flight?

Answer 9

They don’t.

Question 10

How does rime ice form?

Answer 10

Larger percentage freezes compared to clear ice due to smaller droplets.
As the moisture freezes bubbles of air are trapped.
Middle level cloud: As and Ac
Low level cloud: St, Sc and Ns

Question 11

How does mixed ice form?
What temperature?

Answer 11

Combination of clear and rime ice.
Forms near transition between small and large droplets.
-20 degrees for Cu/Cb
-10 degrees for Ns
-20 degrees for Ns with orographic lifting.

Question 12

How is hoar frost formed?

Answer 12

On a calm clear day through sublimation.

Question 13

What is a cold soaked wing?

Answer 13

Fuel in the wings cools at high altitudes.
Therefore icing can be formed at low levels due to the cold wing, as water vapour is found in greater quantities.

Question 14

Where does Icing accumulate on the engine?

Answer 14

On the fan blades.

Question 15

What is high altitude Ice crystal icing?

Answer 15

When Large quantities of Ice crystals are present, icing can occur at high altitudes.
Found at top of Cbs, squall lines and tropical storms.

Question 16

What are the issues provided with Ice crystal icing?

Answer 16

Engine damage.
Reduction in power.

Question 17

Describe the process and situation regarding frozen rain (nimbostratus).

Answer 17

Warm front on left of cloud, with a higher freezing level compared to the other side of the cloud. This creates a rain ice triangle.

Question 18

How does Ice form in a piston engine?

Answer 18

Fuel evaporation cools the chamber allowing Ice to form.

Question 19

What temperature does carb icing form?

Answer 19

Well above 0 degrees.

Question 20

Regarding air temp and dewpoint, when is icing most prominent?

Answer 20

When they are very similar.

Question 21

What is High level clouds (cirrus, cirrostratus, cirrocumulus) risk of icing?

Answer 21

Very low risk. Very little water content.

Question 22

What is middle level clouds (altostratus, altocumulus) icing risk?

Answer 22

Light to moderate.
Depending on the freezing level, clear ice is possible between FZL to +5000’, above this rime ice could occur.

Question 23

What is low level clouds (stratus, stratocumulus, cumulus) risk of icing?

Answer 23

Light to moderate.
Depends on water content.

Question 24

What is low level clouds (cumulonimbus, nimbostratus) risk of icing?

Answer 24

Moderate to servere.
Can contain large water content.
Mostly clear ice.

Question 25

What can orographic intensification effect?

Answer 25

Can increase the severity of icing cloud.