Chapter 15 Adverse Weather - Icing

Question 1

Define drizzle

Answer 1

Uniform precip of raindrops (less than 0.5mm diameter)

Question 2

Define fog

Answer 2

Water droplets that reduce visibility to less than 1000m

Question 3

Define frost

Answer 3

A deposit of ice having a crystalline appearance

Question 4

Define slush

Answer 4

Water saturated snow which with a heel-toe slap down motion against the ground, will be displaced with a splatter

Question 5

Define compacted snow

Answer 5

Snow which has been compressed into a solid mass which resists further compression

Question 6

Define snow

Answer 6

Precip of ice crystals mostly branched in form of six pointed stars, these crystals are isolated or agglomerate to form snowflakes

Question 7

Define dry snow

Answer 7

Snow when ambient temp is below freezing

Question 8

Define wet snow

Answer 8

When the ambient temp is near or above freezing

Question 9

What is the effect of frost on the upper wing surfaces on stall speed and stall angle?

Answer 9

• Stall speed increases by 5%

- stalling angle reduces by 3 degrees

Question 10

What is the effect of frost on the upper wing surfaces on lift?

Answer 10

Reduction in lift of up to 30%

Question 11

What is the effect of frost on the upper wing surfaces on drag?

Answer 11

Increases by up to 40%

Question 12

What are the other impacts of ice?

Answer 12

• reduced control effectiveness
• control jamming
• effects pitot tubes and static ports
• impact damage

Question 13

What is the clean aircraft concept?

Answer 13

• all critical surfaces clear of ice
• no more than 3mm of frost on underside of wings
• max 3mm of frost of fuselage as long as paint markings can be seen

Question 14

What are the three approved ground de-icing methods?

Answer 14

• fluids
• hot air
• manual sweeping

Question 15

What colour is type 1 fluid?

Answer 15

Orange

Question 16

What colour is type 2 fluid?

Answer 16

Straw coloured

Question 17

Describe type 4 fluid

Answer 17

Uses advanced thickening agents to increase holdover time. The require a relatively high airspeed. Coloured green

Question 18

Describe the one step de-icing and anti-icing technique

Answer 18

Describe the two step de-icing and anti-icing technique

Question 19

When does holdover time begin?

Answer 19

When the final application of anti icing fluid commences

Question 20

What must be done if the holdover time expires before takeoff?

Answer 20

Treatment must be done again

Question 21

What cannot be done with regards to anti icing fluid?

Answer 21

Must never receive an anti icing coating directly on top of the previous one

Question 22

Who is responsible for a failed de-ice/anti-ice procedure?

Answer 22

• If it is airport contracted then it’s the airports responsibility
• If it is operator contacted then it’s the operators responsiblilty