Chapter 15 Adverse Weather - Icing Flashcards
Define drizzle
Uniform precip of raindrops (less than 0.5mm diameter)
Define fog
Water droplets that reduce visibility to less than 1000m
Define frost
A deposit of ice having a crystalline appearance
Define slush
Water saturated snow which with a heel-toe slap down motion against the ground, will be displaced with a splatter
Define compacted snow
Snow which has been compressed into a solid mass which resists further compression
Define snow
Precip of ice crystals mostly branched in form of six pointed stars, these crystals are isolated or agglomerate to form snowflakes
Define dry snow
Snow when ambient temp is below freezing
Define wet snow
When the ambient temp is near or above freezing
What is the effect of frost on the upper wing surfaces on stall speed and stall angle?
- Stall speed increases by 5%
- stalling angle reduces by 3 degrees
What is the effect of frost on the upper wing surfaces on lift?
Reduction in lift of up to 30%
What is the effect of frost on the upper wing surfaces on drag?
Increases by up to 40%
What are the other impacts of ice?
- reduced control effectiveness
- control jamming
- effects pitot tubes and static ports
- impact damage
What is the clean aircraft concept?
- 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
What are the three approved ground de-icing methods?
- fluids
- hot air
- manual sweeping
What colour is type 1 fluid?
Orange
What colour is type 2 fluid?
Straw coloured
Describe type 4 fluid
Uses advanced thickening agents to increase holdover time. The require a relatively high airspeed. Coloured green
Describe the one step de-icing and anti-icing technique
Describe the two step de-icing and anti-icing technique
When does holdover time begin?
When the final application of anti icing fluid commences
What must be done if the holdover time expires before takeoff?
Treatment must be done again
What cannot be done with regards to anti icing fluid?
Must never receive an anti icing coating directly on top of the previous one
Who is responsible for a failed de-ice/anti-ice procedure?
- If it is airport contracted then it’s the airports responsibility
- If it is operator contacted then it’s the operators responsiblilty
