1- At temperatures of between 0oC and -10oC clouds consist of:
Entirely water droplets.
Entirely ice crystals.
Mostly water vapour.
Mostly supercooled water droplets and a few ice crystals.
2- Turbulent clouds are most serious from the icing standpoint because:
Strong vertical currents mean that a predominance of large supercooled water droplets will be present.
Strong vertical currents mean that a predominance of small supercooled water droplets will be present.
Turbulent clouds produce hail which sticks to the aircraft.
Turbulent clouds indicate a low freezing level.
3- Hoar frost forms on an aircraft when:
The aircraft suddenly enters a cloud at below freezing temperature.
he aircraft in sub zero clear air suddenly enters a colder region.
The aircraft in sub zero clear air suddenly enters a warmer moist region.
The aircraft suddenly enters a cloud which is at higher temperature than the surrounding air.
4- Stratus cloud of limited depth at a temperature of -5o C will most likely give:
Moderate to heavy rime ice.
Moderate to heavy glaze ice.
Light to moderate rime ice.
Light to moderate glaze ice.
5- Most cases of serious piston engine icing occur in cloud, fog, or precipitation with a temperature range between:
- 10ºC to +25ºC
-18ºC to +5ºC
-10ºC to 0ºC
-20ºC to +15ºC
6- Clear ice forms as a result of:
Large supercooled water droplets spreading as they freeze.
Ice pellets splattering on the aircraft.
Small supercooled water droplets splashing over the aircraft.
Water vapur freezing to the aircraft.
7- Orographic uplift in stable conditions gives a strong vertical component to air movement thus supporting larger supercooled droplets in orographically formed cloud. Consideration should also be given to the fact that in this cloud:
The 0ºC isotherm will be higher.
The 0ºC isotherm will be lower.
The lapse rate will be isothermal.
An inversion can be anti-cyclonic.
8- Carburettor icing is unlikely:
In cloud.
At temperatures between -10oC and -30oC.
In clear air.
When the RH is 60%.
9- Flying 50 nm ahead of a warm front out of cloud at 1000 ft in winter, with an ambient temperature of -8oC, there is a strong risk of:
Hoar frost.
Rime icing and carburettor icing.
Structure damage caused by hail.
Clear ice in the form of rain ice.
10- In AS cloud at FL 170 and a temperature of -20oC the airframe icing most likely to be experienced is:
Moderate clear icing.
Light rime icing.
Severe clear icing.
