Pressure Flashcards
In the standard atmosphere at mean sea level, temperature, pressure and lapse rate equal respectively -
+15 degrees C/1013 HPA/2 degrees C/1000 ft
A line on a weather chart joining places of equal pressure is called -
an isobar
Atmospheric pressure is reported and recorded on weather charts in terms of -
millibars or hectopascals
The pressure gradient is the-
change of pressure with distance, measured horizontally at right angles to the isobars
The diurnal variation of pressure is -
the daily variation of pressure independent of that due to the movement and development of pressure systems
Below 5000 ft pressure drops by 1 HPA with an ascent of approximately -
30’
Pressure may be defined as -
force per unit area
The density of air is -
directly proportional to pressure and inversely proportional to temperature
The sea level pressure in the standard atmosphere is defined in Australia as -
1013.2 HPA
The rate at which atmospheric pressure decreases with altitude in a column of air -
decreases and is dependant on the mean temperature of the column
Before take off for a cross country flight planned to cruise at FL110, the altimeter subscale should be set to
local QNH fi known or aerodrome elevation
What effect does density have on aircraft performance?
good performance occurs when density is high
If the altimeter subscale setting is 1013 HPA the altimeter will read
QNE, px height
While in level flight with the area QNH correctly set, the altimeter indicates the aircraft’s -
approximate height above mean sea level
While cruising at or below A100, the altimeter subscale setting to be used is -
local QNH of a point within 100 m of the aircraft or Area QNH
Aerodrome level pressure is known as -
QFE
The accepted relationship between pressure in hectopascals and height in the lower layers of the atmosphere is-
1 HPA/30 ft
What is the relationship between pressure and altitude?
increase in altitude results in a decrease in pressure
The QNH altimeter setting is the-
subscale setting at which the altimeter indicates airfield elevation on landing
When flying from an area of high pressure into an area of low pressure the altimeter will -
over-read
The correction applied to station level pressure to obtain the QNH assumes -
the density of a column of air extending down to mean sea level is independent of
temperature at station
The correction applied to station level pressure to obtain Meteorological MSL pressure (known as OFF) assumes the density of a column of air extending from the station to MSL-
increase with a decrease in height and depends on the outside air temperature at the station
