Icing

Question 1

Ice is bad because:

Answer 1

Mass - stall speed
Drag - require more power
Changes aerofoil
Changes flow of air into the engine
Engine stall / surge
Jam control surfaces
Limits vis
Blocks sensors.

Question 2

Airframe icing occurs below 0°^c with the exception of

Answer 2

hoar frost

Question 3

World meteorological organisation defines
SCWD
SLD
as?

Answer 3

Supercooled water droplets -
Supercooled large droplets

Question 4

Clear ice aka?

Answer 4

Glaze ice

Question 5

Supercooled water droplets are unstable are waiting for a nucleus which can be

Answer 5

an aircraft

Question 6

Orographic lifting - what should this warn you of?

Answer 6

BAD

Question 7

Clear Ice/Glaze Ice:

Answer 7

Clear Ice/Glaze Ice: large SCWD, 0o to -10 or -15oC, clear appearance, heavy, rapid accretion over airframe, FZRA

Question 8

Rime Ice:

Answer 8

Rime Ice: small SCWD, 0^o to -25^oC, Brittle, Forms on leading edges, Opaque in appearance due trapped air

Question 9

Mixed Ice:

Answer 9

Mixed Ice: both small and large SCWD, dense NS cloud

Question 10

Hoar Frost:

Answer 10

Hoar Frost: sublimation on airframe

Question 11

Packed Snow:

Answer 11

Packed Snow: mixture of frozen water and ice crystals or snow flakes

Question 12

Is snow a danger to flight?

Answer 12

No, but it is a hazard for ground operations

Question 13

Freezing rain / drizzle
FZRA / FZDZ
how big and what do they form?

Answer 13

500 microns
supercooled large droplets

Question 14

Freezing rain requires (3)

Answer 14

The rain/drizzle droplets must be supercooled at or below (ish)
Cold airframe
Drops must form in a relatively warm cloud before falling though a very cold layer of the atmosphere

Question 15

The rain ice triangle describes?

Answer 15

Conditions for rain ice
You are in cold air above the freezing level
Rain cloud is in warm air below the freezing level
BUT you are at the some height due to the different air masses.

Question 16

What factors affect the type of airframe icing?

Answer 16

Size and quantity of supercooled water droplets
Shape of the wing
Orographic intensification
Kinetic heating
Concentration of liquid water

Question 17

In relation to engines, Ice accumulates:

Answer 17

around engine intakes, builds up on fan blades

Question 18

Carb ice:

Answer 18

can occur in temperature well above 0oC

Question 19

High Ice Water Crystal:

Answer 19

primarily found at tops of CBs, squall lines and tropical storms

Question 20

Ns and Cb clouds give:

Answer 20

moderate to severe risk of icing

Question 21

Orographic effect can:

Answer 21

increase the severity of icing in cloud