General MET Knowledge Flashcards
What does ISA stand for?
International Standard Atmosphere
What does OAT stand for?
Outside Air Temperature
What are the 5 Main Layers of the Atompshere?
- Troposphere (Lowest)
- Stratosphere
- O Zone (In Stratosphere)
- Mesosphere
- Thermosphere (Highest)
What is the Temperature at the Top of the Troposphere?
-56.5 Celsius
What is the ISA Sea Level Temperature?
15 Celsius
What is the ISA Rate of Change of Temperature (Lapse Rate)?
1.98 Celsius per 1000ft
2 Celsius for calculations
What is an Adiabatic Atmosphere?
An Atmosphere which changes with temperature
What % of Water Vapour is in the Troposphere?
99%
What is Dry Air Composed of?
- 78% Nitrogen
- 21% Oxygen
- 1% Other Gases
What are the Other Gases that make up Dry Air?
- Carbon Dioxide
- Carbon Monoxide
- Argon
- Hydrogen
- O Zone
What % of the Atmosphere is Water Vapour at Low Levels?
4%
Where is 1/2 of the Mass of Water Vapour?
Below 1.5km
In ISA Conditions, where is the Tropopause? And what is the Temperature?
36090ft
-56.5 Celsius
What happens to Temperature in the Tropopause?
It no longer decreases with temperature
In Real World Conditions, what happens with the Tropopause?
It changes height with seasons, location and the temperature of the surface. It can be as high as 65,000ft around the equator
Where are Jet Streams Found?
Just below the tropopause
Where is most of the O Zone Layer Found?
90% is between 20 and 30km
What does the O Zone Layer do?
It absorbs short wave (UV) radiation, and causes the temperature increase in the stratosphere. It contains toxic gases and causes a decrease in cabin air quality
What is ISA Sea Level Pressure
1013.25hPa or 29.92 InHg (Inches of Mercury) or 760 mmHg (Millimetres of Mercury)
What is the Rate of Change of Temperature through the Atmosphere Known As?
Lapse Rate
Pressure Lapse Rate
1hPa per 30ft (9m)
At what Altitude is Pressure Half at AMSL (High Level)? And what is the Pressure?
18,000ft and 500hPa
What is Air Density at AMSL?
1.225Kg/m^3
What are Temperature Deviations?
Where the actual temperature doesn’t match the ISA temperature for that altitude
What does the MTOW have to be Greater than to get Instantaneous Wind Reports?
5700kg
Does ATIS use True or Magnetic North?
Magnetic North
Do METAR and SPECI use True or Magnetic North?
True North
