C03 - Atmospheric Pressure Flashcards
What type of Atmospheric Pressure is found in bad weather?
Low Air Pressure.
What type of Atmospheric Pressure is found in good weather?
High Air Pressure.
Falling Air Pressure is associated with what type of weather?
Approaching bad weather.
Rising Air Pressure is associated with what type of weather
Approaching good weather.
At low levels, what type of pressure is commonly found?
High Pressure.
At high levels, what type of pressure is commonly found?
Low Pressure.
The pressure caused solely by the effect of gravity on a mass of air is called what?
Static Pressure.
1 mbar is equal to how many hPa?
1 hPa.
What is the formula for Pressure?
P = F ÷ A.
Acceleration of Mass due to the Earth’s gravity is recorded as?
1g.
Earth’s gravity is a ‘____’ force?
Constant.
True or False. Air Mass variability causes Atmospheric Pressure variability?
True.
The ‘____’ the mass of overlying air, the greater the Atmospheric Pressure?
Greater.
The lower the mass of overlying air, the ‘____’ the Atmospheric Pressure?
Lower.
The denser the air, the ‘____’ the pressure?
Higher.
What is a Synoptic Chart?
A diagram of variations in surface pressure.
What is the common datum used in a Synoptic Chart?
Mean Sea Level.
Define QFF?
The Mean Sea Level Pressure of a reporting station corrected for Elevation.
Define Pressure Gradient Force?
A force that tries to drive air from an area of High Pressure to an area of Low Pressure.
The greater the pressure difference, the ‘____’ the Pressure Gradient Force?
Greater.
What two attributes to a greater Pressure Gradient Force?
- Air moves faster.
- Stronger Wind.
What is suggested when having Isobars closer together (2)?
- Stronger PGF.
- Stronger Winds
What is suggested when having Isobars further away (2)?
- Weaker PGF.
- Weaker Winds.
Strong PGF is known to be associated with which type of pressure?
Low.
Weak PGF is known to be associated with which type of pressure?
High.
When does the highest pressure occur during the day?
10:00hrs and 20:00hrs.
When does the lowest pressure occur during the day?
04:00hrs and 16:00hrs.
Pressure decreases with Height at a ‘____’ rate?
Decreasing.
What is the Pressure Lapse Rate formula and its values of measurement (3)?
- (96 x T°) ÷ P.
- T = Temperature in Kelvin.
- P = Pressure in hPa.
According to ISA conditions what is the Pressure Lapse Rate?
27 feet per 1 hPa.
Define QFE?
Atmospheric Pressure at an aerodrome reference point.
An Altimeter set to QFE will read ‘____’ at the aerodrome?
0ft.
When airborne, an Altimeter set to QFE will read ‘____’?
Height above the aerodrome reference point.
Define QNH?
Atmospheric Pressure which has been mathematically adjusted down to Mean Sea Level.
Define SPS?
Standard Pressure Setting is the Mean Sea Level pressure of 1013.25 hPa.
When will Aircrafts use Standard Pressure Setting and why?
To have a common datum when not flying close proximity to terrain/ground.
Height using Standard Pressure Setting are known as ‘____’?
Flight Levels.
What is 27,500ft in Flight Level?
FL 275.
What is 7,000 in Flight Level?
FL 070.
Define QFF?
Similar to QNH but uses the actual pressure change and temperature, rather than ISA conditions.
For airfields above sea level, in warm air QFF is ‘____’ than QNH?
Lower.
For airfields above sea level, in cold air QFF is ‘____’ than QNH?
Higher.
For airfields below sea level, in warm air QFF is ‘____’ than QNH?
Higher.
For airfields below sea level, in cold air QFF is ‘____’ than QNH?
Lower.
What is the Temperature and Pressure at 0ft (2)?
- +15°C.
- 1013.25 hPa.
What is the Temperature and Pressure at 4,700ft / 1.5km (2)?
- +5.5°C.
- 850 hPa.
What is the Temperature and Pressure at 9,800ft / 3km (2)?
- -4.6°C.
- 700 hPa.
What is the Temperature and Pressure at 18,000ft / 5.5km (2)?
- -21.2°C.
- 500 hPa.
What is the Temperature and Pressure at 30,000ft / 9.15km (2)?
- -44.4°C.
- 300 hPa.
What is the Temperature and Pressure at 38,600ft / 11.75km (2)?
- -56.5°C.
- 200 hPa.
