Midterm Flashcards
What is atmospheric pressure
a force caused by the weight of all the air in a column above a particular point and is directed in all directions at a particular point
in what way is sea level pressure rather than station pressure more appropriate and useful for meteorology and aviation
the calculation of MSL pressure provides a more accurate representation of pressure over a region by removing the effects of the station pressure variation caused by differing elevations
(t/F) for any airport at any elevation above sea level, the pressure is always less than the Mean Sea Level Pressure regardless of weather conditions
true
a temperature of 50 F is what C
10C
a line on an aviation weather map or an aviation hazard chart that connects points of constant temperature is:
isotherm
a line of constant pressure
isobar
why is the tropopause higher over the tropics than middle latitudes
colder denser air over the poles vs warmer not as dense air in the tropics
What is ISA used for
pressure altimeter calibrations, aircraft performance calculations, and aircraft design
in all atmospheric layers, a rising parcel of air expands as it rises because pressure always decreases with altitude; thus the rising parcel of air cools as it rises (T/F)
true
if the air is saturated:
no additional water vapor can exist in air
what is dew point depression
numerical difference between the air temperature and the dew point temperature
what is dew point
temperature to which the air would need to be cooled to become saturated
What is the heat index directly correlated to
air temperature and dewpoint
if either increase the heat index increases
what is absolute humidity
flat out amount of water in the air (no temperature consideration)
what is relative humidity
water vapor to the temperature of air
percentage of how much water the air could be holding
what is true altitude
MSL
When flying at FL180 (18,000 ft MSL) with an altimeter setting of 29.92, if the aircraft flies into an area of decreasing pressure that is lower than the pressure defined in the International Standard Atmosphere, the aircraft will be flying
lower than the altimeter indicates
If you wanted an altimeter to read “0” when on the runway, regardless of field elevation of the airport,, what would you enter as an altimeter setting?
the airfield’s station pressure
When flying at an altitude that has temperatures colder than what the International Standard Atmosphere depicts for that altitude (as well as above and below that point), the indicated altitude is more likely to be:
greater than true altitude
(T/F) At the location of where a particular pressure reading is taken, the pressure altitude at that location is the altitude at which that particular pressure reading exists in the International Standard Atmosphere.
true
(T/F) Corrected (Approximately True) Altitude is indicated altitude corrected for the temperature of the air column below the aircraft, the correction being based on the estimated deviations of the existing temperatures from the International Standard Atmosphere temperatures.
True
what are three specific causes of altimeter errors due to a nonstandard temperature
temperature error
pressure error
mountain effect
What does higher density altitude cause
proportionally higher true air speeds and ground speeds for a given indicated air speed.
Which type of front is the biggest aviation concern
occluded
