Revision Tests Flashcards
A katabatic wind-
A downslope of cold air
The surface wind around an area of low pressure in the southern hemisphere-
Clockwise and inwards
If the wind direction changes in a clockwise direction it is said to-
Veer
The Coriolis force in the southern hemisphere acts-
At right angles to the direction of the wind, causing a deflection to the left
A land sea breeze is a wind that blows from the-
Land to sea during the night
Close isobars mean-
Strong winds
A wind caused by uneven heating in coastal regions flows-
From the sea by day and from the land at night
If the forecast wind is 030/20kt, it will blow-
From 030T
When flying towards a low in the southern hemisphere, an aircraft would experience-
Left Drift
Within the friction layer, with increasing height, the wind-
Backs
If you stand with your back to the wind in the southern hemisphere, the region of low pressure will be-
On your right
The friction layer extends up to about-
3000ft
With the passage of a cold front in the southern hemisphere-
What happens to:
- Wind
- Temperature
- Pressure
The wind backs, the temperature falls and the pressure rises
Warm fronts always lie along ridges and cold fronts always lie along troughs- TRUE OR FALSE
False
A cold front usually lies along a-
Trough of low pressure
A cold air mass is characterized by-
Unstable conditions, cumuliform cloud
A defined boundary between two air masses is called a
Front
Warm air masses are characterized by-
Stable and hazy conditions
A cold front is a zone where-
Cold air is displacing warm air at the surface
A warm front is a zone where-
Warm air slides over cold air at the surface
With the passage of a warm front in the southern hemisphere-
The wind backs, the temperature rises and the pressure fall decreases
Following the passage of a warm front, the most likely weather scenario would be-
Nil significant weather
The approach of a warm front would be indicated by-
High level cloud, followed by mid level cloud and eventually extensive nimbostratus
Frontal thunderstorms would be triggered-
By the passage of a cold front
The North West Monsoon-
Brings unstable moist air to Darwin
The inter tropic convergence zone is a boundary between-
Airstreams originating in the northern and southern hemisphere
The inter tropic convergence zone is found near-
The equator
The major hazard of a tropical cyclone to an aircraft is-
Severe turbulence
A strong wind across a mountain range will produce-
Strong down currents on the lee side
The cyclone season in Australia is from-
November to April
You would expect to encounter the most severe turbulence when lying at a height of 3000ft above the ground at a-
Rapidly moving cold front with unstable air
The approach of a tropical revolving storm is heralded by-
Falling pressure with increasing wind speed
The most pronounced thermal turbulence is found-
In the afternoon over land
If the air is unstable in the lower layers only, the following conditions could be expected-
Bumpy with cumulus cloud
The characteristics of warm air masses are-
Stable lapse rate and stratiform cloud
Cold streams passing over south eastern Australia are usually unstable because-
The surface over which they pass is warmer than the air
The pressure gradient force acts-
At right angles to the isobars, towards the lower pressure
The strength of the pressure gradient force depends most on-
The spacing of isobars
Coriolis force explains the tendency of wind to-
Turn left in the southern hemisphere
Surface wind, when compared to the gradient wind flow, is found to be-
Veered to the right and slower
Compared to the gradient wind flow, the surface wind over land will have-
Veered by 30 degrees and slower by two thirds
The term geostrophic wind refers to the steady flow of wind-
Along straight isobars
Anti-cyclonic flow occurs-
About a high in the southern hemisphere
Cyclonic flow occurs-
About a low in the southern hemisphere
A katabatic wind will tend to reinforce-
A land breeze
The variations in wind and temperature which normally occur with the passage of a cold front are-
The wind backs and temperature falls
A fohn wind is likely to result in-
A lower humidity in the lee of the mountain at low level
Describe a squall line-
A low cloud moving rapidly in the warm air ahead of a cold front
At which latitude would there be the greatest difference between the actual wind and gradient wind at 5000ft AGL-
5 Degrees South
Describe backing wind-
It is changing direction anti-clockwise
For katabatic wind to form there must be-
A surface inversion
Squall lines are most often associated with-
Thunderstorms
Surface friction causes-
A decrease in Coriolis effect
An aircraft heading directly from a high pressure system to a low pressure system will-
Drift towards the left
Conditional stability is said to exist when-
Saturated air is unstable by dry air is stable
Which conditions are most likely to produce fog-
Nil cloud and light winds
In what stage of a thunderstorm would lightening be most frequent-
During the mature stage
Where is hail most likely to be encountered inside a thunderstorm-
Between 10,000-30,000ft
In which conditions are thunderstorms most likely-
latitudinal heating of a fast moving cold moist air stream
Which cloud type is most likely to produce virga-
Thin Altostratus
What is most likely to be encountered in nimbostratus cloud-
Heavy continuous rain
The lifting of fog may be caused by-
Increase in wind strength
The most common way for cumulus cloud to form is-
Rising air being cooled by expansion
Which phenomena in a thunderstorm causes low level wind shear at some distance away from the cell-
Downdraught
Where are tornadoes most likely to be encountered?
With widespread severe thunderstorms
Latitudinal heating of a cold air stream produces-
Instability, possibly thunderstorms
A thunderstorm can occur well after a cold front has passed because-
The surface over which the cold air is passing is warmer than the cold air mass
Advection fog forms when-
Warm air passes over a cold surface
Thunderstorms are most likely to form when atmospheric conditions are-
Humid and unstable
A wind blowing up sloping terrain during the day could be-
Anabatic
A hazard at all levels in a CB is-
Turbulence
The main hazard posed to aircraft by airframe icing is-
Reduced aerodynamic efficiency
The type of icing likely to be encountered above the freezing level in stratiform cloud is-
Rime ice
The type of icing likely to be experienced just above the freezing level in a cumuliform type cloud is-
Clear ice
The formation of clear ice requires-
Large droplets and an OAT between 0 degrees and -15 degrees
The most severe airframe icing is found-
Between 0 degrees and -15 degrees
Two hazards posed to aircraft around a thunderstorm could be-
Turbulence and hail
The minimum OAT at which clear airframe icing would be unlikely is-
+5 degrees
When a thunderstorm is in the vicinity of an airport, one hazard preventing aircraft landing and taking off is-
Wind shear
Airframe icing is most likely-
With visible moisture at temperatures below freezing
The type of icing likely to be encountered in an orographic cloud when the OAT is -10 degrees would be-
Clear ice
The icing experienced when flying through the rain in temperatures below freezing would be-
Heavy clear
When avoiding a thunderstorm, horizontal separation should be at least-
20nm
While on an approach to land, an aircraft encounters an abrupt decrease in the headwind component. The initial effect will be-
A decrease in airspeed and an undershoot tendency
The most hazardous form of airframe ice is-
Clear ice
Clear icing in Australia is normally associated with the following clouds-
Large cumulus, cumulonimbus and nimbostratus
Before flight, the pilot notices a thin white crystalline deposit over the wings-
Should be removed before attempting to takeoff
Dangerous icing is frequently found in-
NS Cloud
It is safe to avoid thunderstorms by flying under them. TRUE or FALSE?
False
The white crystalline deposit of ice taht forms on all exterior surfaces of an aeroplane when water vapour turns directly into ice is called-
Hoar Frost
The troposphere-
Contains most of the water vapour of the atmosphere and the temperature generally decreases with height
With increasing altitude in the stratosphere, temperature-
Increases
The tropopause is-
A region 8km to 18km above the earths surface at which a marked change in temperature lapse is apparent
In the ISA, the tropopause is found at-
A height of 36,090ft
One of the major differences between the troposphere and the stratosphere is that the stratosphere-
Has almost no clouds
From the earth’s surface, the vertical structure of the atmosphere is-
Troposphere, tropopause, stratosphere
The lapse rate in the stratosphere is due to-
The presence of heat absorbing ozone
The section of the atmosphere in which most weather occurs is the-
Troposphere
The temperature at the base of the stratosphere is the lowest over-
The equator
the temperature in the ISA tropopause is-
-56 degrees
Normally the diurnal range of temperature is greatest at-
Inland location
The diurnal variation of temperature is-
The temperature pattern over 24 hour period
Solar radiation passing through the atmosphere is-
- Absorbed
- Scattered
- Reflected
On an ISA day, you would expect the temperature at an elevation of 4000ft above MSL to be-
+7
The sea-level temperature in the standard atmosphere is-
+15
The change of temperature for an increase in altitude known as-
The lapse rate
The primary cause of weather is-
Temperature differential
A line on a weather chart joining places having the same temperature is called an-
Isotherm
Radiant energy arriving from the sun is termed-
Insolation
Our weather is due to the atmosphere being heated mainly by-
Radiation from the earth
In the standard atmosphere at mean sea level, temperature, pressure and lapse rate equal respectively-
+15
1013 HPA
2degrees/ 1000ft
A line on a weather chart joining places of equal pressure is called-
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, measure 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 5,000ft pressure drops at 1 HPA with an ascent of approximately-
30ft
Pressure may be defined as-
Force per unit area
The density of air is-
Relationship to pressure and temperature
Directly proportional to the pressure
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 dependent on the mean temperature of the column
Before takeoff for a cross country flight planned at FL110, the altimeter subscale should be set to-
Local QNH if 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-
Pressure height
While in level flight with the area QNH correctly set, the altimeter indicates the aircraft-
Approximate height above mean sea level
Aerodrome level pressure is known as-
QFE
While cruising at or below A100, the altimeter subscale setting to be used is-
Local QNH of a point within 100nm of the aircraft or area QNH
The accepted relationship between pressure in hectopascals and height in the lower layers of the atmosphere is-
1 HPA/ 30ft
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 QNH assumes-
The density of a column of air extending down to mean sea level is independent of temperature at the station
The correction applied to station level pressure to obtain meteorological MSL pressure (Known as QFF) 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
When a parcel of air becomes saturated and condensation occurs-
Latent heat is released
The relative humidity is-
The percentage degree of saturation
The dew point is the temperature-
To which a sample of moist air must be cooled at constant pressure for it to become saturated
When water droplets in the liquid state freeze-
Latent heat is released
The relative humidity is measured using a-
Psychrometer
A parcel of air has a temperature of +15 and relative humidity of 80%. A temperature rise of 10 degrees will cause-
The relative humidity to decrease
The water vapour held in saturated air is-
Invisible always
When the temperature and dew point are the same-
The relative humidity is 100%
The reading of wet and dry bulb thermometers at meteorological stations serves to calculate-
Humidity
The relative humidity is the-
The ratio of the amount of water vapor present to the amount that could be held in a sample of air
When the air temperature at a particular level is higher than that existing at a lower level-
An inversion exists
Warm air is rising adiabatically above a ploughed field, surface temperature +21. The dew point at the cloud base is +3. The cloud base and freezing level respectively are approximate-
6,000ft and 8,000ft
If the ELR is between 1.5 and 3 the air is-
Stable for dry air and unstable for staurated air
Above the condensation level the lape rate of rising air will-
reduce from the dry adiabatic lapse rate to the smaller saturated adiabatic lapse rate
An inversion results in-
extremely stable conditions above
Warmer temperatures above a colder layer of air indicates-
An inversion
When the ELR is greater than the DALR, dry air is-
Unstable
The dry adiabatic lapse rate is-
3/ 1,000ft
When the SALR is greater than the ELR, saturated air is-
Stable
The actual change of temperature for an increase in altitude is known as-
The environmental lapse rate
Warm air is rising adiabatically above a ploughed field, surface temperature +21. The dew point is +3. Allowing for the dew point lapse rate, the cloud base and freezing level respectively are approximately-
7,500ft and 7,000ft
The average rate of decrease in temperature per 1,000ft of height is approx-
2
An adiabatic process is one-
In which no heat is transferred into or out of the system
The area in which a tropical cyclone is most likely to form is-
over the pacific ocean near 15 degrees
During the mature stage of a tropical cyclone the central surface pressure-
Remains constant
The temperature at the base of the stratocumulus cloud is minus 1 degree. The cloud is 2,500ft thick and the temperature at the cloud tops is -5. Flight within the cloud is likely to encounter-
Rime ice
In which cloud type is clear ic most likely in flight above freezing level?
Nimbostratus
In the vicinity of mountain waves, the rotor zone might be located-
Under lenticular cloud
Slant visibility in fog causes-
The runway to be visible over the op but not in the circuit area or final
The situation in which clear icing is most likely-
Above freezing level on climb in large cumuliform cloud
The process involved in the formation of hoar frost is-
Deposition of ice directly from water vapour mixed with the air
The set of conditions most likely to produce mountain wave activity is-
A stable layer of air near the top of a ridge
The temperature range most likely to produce rime ice is-
-10 to -20
Clear ice is most likely to form on an aircraft flying in-
Thick altostratus cloud
The cloud type often associated with mountain wave activity is -
Lenticular and rotor clouds
The most likely cause of turbulence overland on a hot day is-
Thermal activities
