Icing Flashcards
What are 4 effects of icing
- Increase in weight
- Alters CoG
- Increased drag
- Vibrations
REMEMBER: Increased Weight and Drag Can Vibrate
What are 4 risks of icing
1. ?? of p??
2. ?? of a i??
3. ?? visibility
4. ?? of a?? L??
- Blockage of ports
- Blockage of air intakes
- Reduced visibility
- Loss of aerodynamic lift
P I V L
Ports Intakes Visibility Lift
The worst icing occurs in what temperature range
0℃ to -12℃
Where does icing generally occur
Cloud less than 0℃
What is super cooled water droplets
Water cooled below freezing (liquid state still)
Unable to form to ice as no particle exists to trigger transition from liquid to solid
What are the 4 classifications of icing
i.e. ____ icing
- Trace
- Light
- Moderate
- Servere
What type of icing is defined below
Ice becomes perceptible. Rate of accumulation of ice is slightly greater than the rate of loss. Not hazardous unless encountered for more than one hour
TRACE
What type of icing is defined below
Rate of accumulation may create a problem for flight in this environment for one hour. Unless encountered for one hour or more, de-icing/anti-icing equipment and/or heading or altitude change not required. Occasional use of de-icing equipment removes ice
LIGHT
What type of icing is defined below
The rate of accumulation is such that even short encounters become potentially hazardous. De-icing/anti-icing require to remove/prevent accumulation or heading or altitude change or diversion required.
MODERATE
What type of icing is defined below
The rate of accumulation is such that de-icing / anti-icing equipment fails to reduce or control the hazard. De-icing / anti-icing plus immediate heading or altitude change or diversion required
SEVERE
Which 2 cloud types pose the biggest risk of icing
- Cumulus
- Orographically formed
What are the in-flight icing formation risk temperature ranges;
HIGH RISK;
1.Cumulus Clouds
2.Stratiform Clouds
3.Rain and Drizzle
- 0℃ to -20℃
- 0℃ to -15℃
- 0℃ and below
What are the in-flight icing formation risk temperature ranges;
MEDIUM RISK;
1. Cumulus Clouds
2. Stratiform Clouds
- -20℃ to -40℃
- -15℃ to -30℃
What are the in-flight icing formation risk temperature ranges
LOW RISK;
1. Cumulus Clouds
2. Stratiform Clouds
- < than -40℃
- < than -30℃
What type of icing is defined below;
- Formed from water droplets impacting airframe
- Brittle
- Semi opaque (trapped air)
RIME ICE
What type of icing is defined below;
- Formed as water droplets flow backwards along airframe
- Dense weight
- Difficult to remove
- Creep to parts of airframe not protected by anti-icing measures
CLEAR ICE
What type of icing is defined below;
- Found on cold mornings on structures at ground level
- Formed by sublimation
- Dramatically affects aerodynamics
HOAR FROST
What type of icing is defined below;
- Rain falling from cloud descends into colder air
- Very difficult to remove
- Associated with warm fronts
RAIN ICE
(Freezing rain)
What are the 4 key factors causing carburettor ice
- PRESSURE
- TEMPERATURE
- WATER VAPOUR
- VENTURI EFFECT
- Reduced pressure in venturi
- Reduced dew point
- Condensing of water vapour
- Temperature drop in venturi (fuel evaporating takes heat energy from the atmopshere)
What is the approximate temperature drop insite a carburettor venturi
25℃ to 30℃
What are the 3 affects of carb icing
1. Ice forms where?
2. There is less what in the engine?
3. The throttle is what?
- Ice forms in venturi
- Less volume of fuel/air mixture to engine
- Throttle immoveable
Carb icing is more likely on COLD or WARM days
WARM DAYS
What is the dominant factor of carb icing
HUMIDITY
What are the 4 key symptoms of carb icing
What you are the pilot might experience in the plane to understand it is suffering from icing
- Decrease in RPM
- Decrease in manifold pressure
- Rough running engine
- Eventual engine failure
What feature is used to melt ice in the carburettor
CARB HEAT
How does a carb heat control work
WARM AIR
Selects different source of intake air
Why will an engine under perform when using carb heat
WARM AIR LESS DENSE
Engine performance is impacted
In a situation where the engine is running roughly and carb icing is assumed to be the cause, one application of carb heat, what may happen
Engine runs even more roughly
Ice melts, water mixes with fuel and air
Warm air is more dense
Both features will cause rougher running engine
What are 2 key reasons why an engine runs rougher when carb is applied
- Ice melting turns to water, which mixes with fuel and air
- Warm air more dense, less air in mixture (less effective)
Which engine type does not have a carb heat control
FUEL INJECTION ENGINES
Do not have carburettors
What are 4 actions a pilot can take against icing
- Apply carb/pitot heat
- Descend to warmer air
- Increase airspeed
- Increase propeller RPM