Wetter Flashcards
List the general features of a low in the northern hemisphere
- Low Pressure
- Cyclone
- Wind is counterclockwise
- Rising air cools dry adiabatic, then moist
- Clouds form
- Bad Wx
Explain the formation of an occlusion
Cold front catches up with warm front and the warm air mass is lifted off the ground.
A Unstable and Cold/ Falling temperature
B Unstable and Falling temperature
C No Change
D Rising temperature
E Stable
There is moderate icing. What happens to thrust, lift, drag and weight of the Aircraft?
- Thrust decreases
- Lift decreases
- Drag increases
- Weight increases
State the temperature range, at which icing in clouds usually occurs.
0 to - 20°C
Which type of icing can you expect in:
- CU/ -5°C
- TCU/ -15°C
- AS/ -11°C
- FZRA
- NS/ -25°C
- Clear
- Rime
- Rime
- Clear
- No ice or Traces
D
List 8 Thunderstorm hazards.
- Microburst
- Lightning
- Hail
- Gusts close to surface
- Severe Turbulence
- Severe Icing
- Rapid Reduction of visibility
- Rapidly lowering ceiling
- Altimeter errors
- Radar/ Radio disturbance
- Aquaplaning
What is the cause of:
a. convective turbulence?
b. mechanical turbulence
A Heating from below
B Strong winds above obstacles or near the surface
Under which circumstances a BW helicopter pilot has to submit a PIREP to ATC?
- Wx is not as forecasted
- Unusual Wx
- Missed approach due to wx
A
- Moderate to strong wind from 220°
- Stratiform clouds
- Continuous precipitation
B
- Fine Wx for Day and Night
- Radiation Fog can develop during night
Explain the expression “void after” in the wx forecast/ briefing process.
Time until the Takoff has to be done, otherwise the Wx will be void.
Initially 3 hours with a possible extension up to 2 hours (5 hours total)
Which meteorological factors have an effect on the night illumination?
- Clouds
- Precipitation
- Ground conditions
Define the term “civil twilight”.
Time before SR or after SS when the Sun is up to 6° below the horizon.
When do you expect “dark night” conditions after SS?
When the sun is at least 16° below the horizon.
Explain the term “moon brightness”.
The moon brightness is the brightness of the horizontal ground caused by the moonlight, given in % of the full-moon-light at the average distance moon - earth in case of full zenith.
Write down the limiting value for the NVG range for flights with night vision goggles.
1,5 km
The weather forecaster expects upcoming snowfall during the planned night flight period. Astronomical illumination values will not change significantly. What is the effect for flying with NVG?
Strong deterioration
The weather forecaster expects dense mist forming during the planned night flight period. Astronomical illumination values will not change significantly. What is the effect for flying with NVG?
Strong deterioration
1900Z/ OVC 19
2100Z/ 4 octas 70
2300Z/ Clear sky 200
Which clouds, visibility, weather phenomena and aircraft icing do you expect at the passage of a cold front type I?
CU, TCU, CB;
poor visibility inside clouds, good outside;
Showers, hail, thunderstorms;
Clear ice
Where do you normally expect a squall line?
Warm sector ahead and parallel to a cold front
Explain the expression “ISOL” in the weather forecast / briefing process
Isolated affected portion; =< 10%
Explain the expression “LOC” in the weather forecast / briefing process
Locally; >10% =< 25%
Explain the expression “FRQ” in the weather forecast / briefing process
Frequent; >25% < 50%
Explain the difference between solid and dotted lines used in the area weather
Solid: Boundary between different prevailing conditions
Dotted: Boundary between different minimum conditions
