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CAA NZ PPL Meteorology study materials
CAA NZ PPL Meteorology study resources

CAA NZ PPL Meteorology practice questions

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Question 1Aviation meteorology theory and weather interpretation

In the Southern Hemisphere, air flowing outward from a high-pressure centre at the surface is deflected in which direction, and why?

  1. Clockwise and outward, because Coriolis force deflects moving air to its left Correct answer.
  2. Clockwise and outward, because Coriolis force deflects moving air to its right
  3. Anticlockwise and outward, because pressure gradient force curves the flow
  4. Anticlockwise and outward, because Coriolis force deflects moving air to its left

Explanation

In the Southern Hemisphere the Coriolis force acts to the left of the wind direction, so air diverging out of a surface anticyclone is turned leftward, giving clockwise outflow. Friction near the surface allows the flow to cross the isobars outward rather than running parallel to them.

Question 2Aviation meteorology theory and weather interpretation

A pilot reads a QNH of 1002 hPa at a coastal aerodrome. Which statement best describes the expected weather and the reason for it?

  1. Unsettled weather with cloud and showers, because converging air rises and cools Correct answer.
  2. Settled clear weather, because low pressure suppresses cloud formation
  3. Strong steady winds with no cloud, because pressure gradient is absent
  4. Fog only, because low pressure always produces radiation fog at the surface

Explanation

A low QNH indicates a depression in which surface air converges and is forced to rise. Rising air cools adiabatically, moisture condenses, and cloud, showers and generally unsettled conditions result.

Question 3Aviation meteorology theory and weather interpretation

A METAR reports wind as 24015G28KT. What does this indicate?

  1. Wind varying between 240 and 280 degrees at 15 knots
  2. Mean wind 280 degrees at 15 knots, gusting to 24 knots
  3. Mean wind 240 degrees at 15 knots, gusting to 28 knots Correct answer.
  4. Wind 240 degrees at 28 knots with a 15-knot variation

Explanation

In the METAR wind group the first three digits give the direction in degrees true, the next two or three give the mean speed, and the digits after G give the peak gust speed. Here the mean is 240 degrees at 15 knots with gusts to 28 knots.

Question 4Aviation meteorology theory and weather interpretation

What is the primary cause of the daytime sea breeze at a coastal aerodrome?

  1. The land heats faster than the sea, so air rises over land and cooler air flows in from the sea Correct answer.
  2. The sea heats faster than the land, so air rises over the sea and flows onshore
  3. Subsidence over the sea increases pressure and pushes air inland
  4. Coriolis force reverses the prevailing gradient wind during the afternoon

Explanation

Land has a lower heat capacity than water, so it warms more quickly under daytime insolation. Air over the land rises, lowering pressure locally, and cooler air flows onshore from the higher-pressure sea to replace it.

Question 5Aviation meteorology theory and weather interpretation

Aerodrome A lies at 2000 ft AMSL and aerodrome B at 600 ft AMSL. The QNH is the same at both. How does the pressure altitude of A compare with that of B?

  1. A has a higher pressure altitude than B Correct answer.
  2. A and B have the same pressure altitude
  3. Pressure altitude cannot be compared without temperature
  4. A has a lower pressure altitude than B

Explanation

Pressure altitude is the altitude in the standard atmosphere corresponding to a given pressure, and pressure falls with height. With a common QNH, the higher aerodrome sits at lower pressure and therefore has the higher pressure altitude.

Question 6Aviation meteorology theory and weather interpretation

Which cloud type is most commonly associated with continuous steady rain ahead of a warm front?

  1. Nimbostratus Correct answer.
  2. Cumulonimbus
  3. Cirrocumulus
  4. Altocumulus castellanus

Explanation

The shallow slope of a warm front produces widespread gentle ascent, giving layered cloud that thickens to nimbostratus with continuous rain. Cumulonimbus and castellanus indicate instability and showery or convective precipitation instead.

Question 7Aviation meteorology theory and weather interpretation

In a tropical region, the freezing level is forecast at 15,000 ft. An aircraft without anti-icing equipment plans to cruise at 12,000 ft in cloud. What is the main icing concern?

  1. Certain rime ice, because temperatures above freezing prevent icing
  2. Possible clear ice if supercooled water is present in the cloud Correct answer.
  3. No icing risk, because the aircraft is below the freezing level
  4. Icing only if the outside air temperature is below minus 20 degrees Celsius

Explanation

Cloud below the freezing level can contain supercooled water droplets that freeze on impact with the airframe. In such conditions, particularly with large droplets, clear or mixed ice can form even though the aircraft is below the 0 degree level.

Question 8Aviation meteorology theory and weather interpretation

An aircraft descends from 8000 ft to 2000 ft while the QNH remains constant at 1013 hPa. What happens to the aircraft's true altitude relative to its pressure altitude?

  1. True altitude stays equal to pressure altitude throughout
  2. True altitude becomes greater than pressure altitude as it descends
  3. True altitude changes only if the temperature deviates from ISA Correct answer.
  4. True altitude becomes less than pressure altitude as it descends

Explanation

Pressure altitude is referenced to the standard atmosphere, so the difference between true and pressure altitude depends on temperature deviation from ISA. With a constant QNH and standard conditions the two remain equal; only non-standard temperature causes a discrepancy.

Question 9Aviation meteorology theory and weather interpretation

What does a TAF group of BECMG FM1800 18020KT 9999 SCT030 indicate?

  1. A temporary fluctuation expected to last less than 30 minutes around 1800
  2. A gradual permanent change beginning at 1800 to the stated wind and visibility Correct answer.
  3. An immediate change at 1800 that will revert by the end of the period
  4. A probability of 30 percent that conditions will occur after 1800

Explanation

BECMG denotes a gradual change that becomes established within the stated time window and then persists. FM1800 gives the start time, and the following groups describe the new prevailing conditions of wind, visibility and cloud.

Question 10Aviation meteorology theory and weather interpretation

A pilot on final approach experiences a sudden increase in headwind and rising air, followed shortly by a decrease in headwind and sinking air. What is the correct interpretation and response?

  1. A windshear encounter with likely undershoot; be prepared to go around Correct answer.
  2. Normal mechanical turbulence; continue the approach unchanged
  3. A microburst encounter; go around and avoid the area
  4. A sea-breeze front; reduce power to maintain the glidepath

Explanation

The sequence of increasing then decreasing headwind with rising then sinking air is classic low-level windshear, often from a gust front or microburst. The performance loss after the headwind drops can cause the aircraft to sink below the glidepath, so the pilot should be ready to go around.

Question 11Aviation meteorology theory and weather interpretation

Which condition is most favourable for the formation of radiation fog at an inland aerodrome overnight?

  1. Clear skies, light winds and high relative humidity Correct answer.
  2. Strong winds with a passing cold front
  3. Warm advection over a cold surface with strong mixing
  4. Overcast skies, moderate winds and dry air

Explanation

Radiation fog forms when the ground cools strongly by long-wave radiation under clear skies and light winds, cooling the air above it to its dew point. High humidity reduces the cooling needed to reach saturation.

Question 12Aviation meteorology theory and weather interpretation

In the Southern Hemisphere, what is the surface wind direction around a low-pressure centre?

  1. Anticlockwise and inward Correct answer.
  2. Clockwise and inward
  3. Anticlockwise and outward
  4. Clockwise and outward

Explanation

Around a Southern Hemisphere depression, the pressure gradient force draws air inward while the Coriolis force deflects it to the left, producing anticlockwise circulation. Friction allows the flow to cross the isobars toward the centre.

Question 13Aviation meteorology theory and weather interpretation

A cold front is approaching an aerodrome. Which sequence of weather is most typical as it passes?

  1. Gradual thickening cloud, then steady rain, then clearing
  2. Clear skies with increasing temperature and veering wind
  3. Persistent low cloud and drizzle with little change in temperature
  4. Sudden wind shift, heavy showers or thunderstorms, then rapid clearing and cooler air Correct answer.

Explanation

A cold front is steep and produces vigorous ascent, giving a sharp wind shift, squally showers or thunderstorms and a marked temperature drop. Because the front is narrow, conditions clear quickly after passage.

Question 14Aviation meteorology theory and weather interpretation

What is the significance of the code 2500 in a TAF visibility group, and what does 9999 represent?

  1. 2500 means 2500 m; 9999 means unlimited visibility above 10 km Correct answer.
  2. 2500 means 2.5 km; 9999 means visibility greater than 10 km
  3. 2500 means 2500 ft cloud base; 9999 means no cloud below 10,000 ft
  4. 2500 means 25 km; 9999 means visibility is not reported

Explanation

Visibility in TAF and METAR is coded in metres, so 2500 is 2500 metres. The code 9999 indicates visibility of 10 km or more, which is the maximum value the group can express.

Question 15Aviation meteorology theory and weather interpretation

Why does the wind typically veer and increase in speed with height in the friction layer?

  1. The Coriolis force is stronger at the surface than aloft
  2. Pressure gradient force weakens with height, turning the wind
  3. Surface friction slows the wind and reduces Coriolis deflection, so aloft the wind is stronger and more geostrophic Correct answer.
  4. Temperature always increases with height, accelerating the wind aloft

Explanation

Near the surface, friction reduces wind speed, which weakens the Coriolis force relative to the pressure gradient force and allows the wind to cross the isobars. With height, friction decreases, the wind speeds up and turns toward geostrophic flow, so it veers in the Southern Hemisphere.

Question 16Aviation meteorology theory and weather interpretation

An aerodrome forecast indicates a QNH of 1030 hPa and a nearby deep low of 985 hPa about 300 nm away. What can be inferred about the wind?

  1. Strong winds, because the pressure difference is large over a short distance Correct answer.
  2. Wind direction cannot be inferred from pressure alone, and speed will be light
  3. Light winds, because pressure gradients are usually weak in anticyclonic conditions
  4. No wind, because the high dominates the local pressure field

Explanation

Wind speed is governed by the pressure gradient, that is the spacing of isobars, not by the absolute pressure value. A 45 hPa difference over roughly 300 nm represents a steep gradient and implies strong winds between the systems.

Question 17Aviation meteorology theory and weather interpretation

During a flight at 9500 ft, the outside air temperature is minus 20 degrees Celsius while ISA temperature at that level is about minus 4 degrees Celsius. What is the effect on the aircraft's true altitude?

  1. True altitude is higher than indicated altitude
  2. True altitude equals indicated altitude
  3. True altitude is unaffected by temperature at that level
  4. True altitude is lower than indicated altitude Correct answer.

Explanation

When the air is colder than ISA, the pressure levels are compressed toward the surface, so the aircraft is lower than the altimeter indicates. Flying from a warmer to a colder region, or operating in cold air, gives a true altitude lower than indicated.

Question 18Aviation meteorology theory and weather interpretation

What distinguishes freezing rain from ice pellets in a TEMPO or SIGMET context for a pilot?

  1. Ice pellets are supercooled droplets, while freezing rain is frozen on impact
  2. Both indicate supercooled water aloft and pose identical airframe icing risk
  3. Freezing rain occurs only above the freezing level, while ice pellets occur only below it
  4. Freezing rain means supercooled droplets that freeze on impact, while ice pellets are already frozen and bounce Correct answer.

Explanation

Freezing rain consists of supercooled liquid droplets that freeze on contact with the airframe, producing rapid and severe clear ice. Ice pellets have already frozen before reaching the surface and indicate a warm layer aloft with a refreezing layer below, so they bounce rather than adhere.

Question 19Aviation meteorology theory and weather interpretation

A pilot plans a VFR flight through a mountain pass where the wind is forecast at 30 knots across the ridge. What hazard should be anticipated?

  1. Smooth laminar flow through the pass with no turbulence
  2. Increased visibility due to downslope warming
  3. Reduced pressure gradient and therefore lighter winds in the pass
  4. Mechanical turbulence and possible lee-side downdrafts near the ridge Correct answer.

Explanation

Strong cross-ridge winds produce mechanical turbulence and lee waves, with downdrafts on the lee side that can exceed the aircraft's climb capability. Pilots should expect turbulent conditions and possible severe downdrafts near ridges and passes.

Question 20Aviation meteorology theory and weather interpretation

What is the primary reason that advection fog forms over the sea and moves inland?

  1. Strong mixing by wind carries fog droplets upward from the surface
  2. Cold air moves over a warm sea and is heated, causing condensation
  3. Warm moist air moves over a colder surface and is cooled to its dew point Correct answer.
  4. The sea surface cools radiatively at night, forming fog in place

Explanation

Advection fog forms when relatively warm, moist air is transported over a colder surface and cooled from below to its dew point. Over the sea this often occurs when air from a warmer region crosses a cooler current, and onshore winds can then carry the fog inland.

Question 21Aviation meteorology theory and weather interpretation

An aircraft is flying from a region of QNH 1020 hPa into a region of QNH 1002 hPa while maintaining a constant indicated altitude. What is the effect on true altitude if the altimeter subscale is not updated?

  1. The effect depends only on temperature, not on QNH
  2. The aircraft becomes progressively higher than indicated
  3. True altitude remains constant because indicated altitude is constant
  4. The aircraft becomes progressively lower than indicated Correct answer.

Explanation

Flying from higher to lower pressure with a fixed subscale setting causes the altimeter to overread, so the aircraft is actually lower than indicated. This is why the subscale should be updated to the local QNH when moving between pressure regions.

Question 22Aviation meteorology theory and weather interpretation

A SIGMET is issued for an area. Which phenomenon would justify it under New Zealand practice?

  1. A temporary reduction of visibility to 8 km
  2. Moderate rain showers over a small area
  3. A forecast of scattered cloud at 4000 ft
  4. Severe turbulence or volcanic ash affecting the safety of aircraft Correct answer.

Explanation

SIGMETs advise of significant en-route weather hazards such as severe turbulence, severe icing, volcanic ash, tropical cyclones and severe squall lines. Ordinary showers, scattered cloud and moderate visibility reductions do not meet the criteria.

Question 23Aviation meteorology theory and weather interpretation

Why is clear ice generally considered more hazardous than rime ice for an aircraft without de-icing equipment?

  1. Rime ice always forms on the tailplane and is therefore less visible
  2. Clear ice is denser, spreads further back and distorts the aerofoil more Correct answer.
  3. Clear ice occurs only in stratiform cloud and is easily predicted
  4. Clear ice forms at higher temperatures where the aircraft is more vulnerable

Explanation

Clear ice forms from large supercooled droplets that spread and freeze slowly, creating dense, irregular accretions that extend well aft of the leading edge. This spoils the aerofoil shape and adds significant weight, giving a greater performance penalty than the rough, forward-facing rime deposit.

Question 24Aviation meteorology theory and weather interpretation

A pilot observes that the wind at the aerodrome has backed from 270 to 210 degrees while pressure has fallen steadily. What is the most likely interpretation?

  1. A warm front or trough is approaching, with deteriorating weather likely Correct answer.
  2. A cold front has passed and pressure is now rising
  3. The wind change is purely diurnal and has no weather significance
  4. A strong anticyclone is building and conditions will improve

Explanation

Backing wind with falling pressure typically indicates the approach of a warm front or trough, where the wind veers with height and the surface wind backs ahead of the system. Conditions often deteriorate with cloud and precipitation as the front nears.

Question 25Aviation meteorology theory and weather interpretation

In a region where the 500 hPa chart shows a deep trough and a strong jet streak, what weather is most likely at the surface downstream of the trough?

  1. Stable stratiform cloud with no precipitation
  2. Immediate dissipation of any existing surface low
  3. Subsidence and clear skies due to upper convergence
  4. Enhanced ascent and possible deep convection or cyclogenesis Correct answer.

Explanation

Downstream of an upper trough, divergence aloft in the exit region of a jet streak encourages ascent and surface pressure falls. This favours deep convection and cyclogenesis, so significant weather is likely in that region.

Question 26Aviation meteorology theory and weather interpretation

What does the abbreviation QNH represent on an aviation weather report?

  1. The aerodrome pressure reduced to mean sea level using the standard atmosphere
  2. The actual pressure at aerodrome level reduced to sea level using aerodrome elevation Correct answer.
  3. The pressure at the standard datum of 1013.2 hPa
  4. The pressure setting that makes the altimeter read zero at the aerodrome

Explanation

QNH is the aerodrome-level pressure reduced to mean sea level using the actual elevation, so that an altimeter set to it reads aerodrome elevation on the ground. It is not corrected using the standard atmosphere, and it does not read zero on the ground.

Question 27Aviation meteorology theory and weather interpretation

In a METAR, what does the group R24/0600 mean?

  1. Runway 24 is closed for 60 minutes
  2. Runway 24 visibility is 600 metres
  3. Runway 24 touchdown zone RVR is 600 metres Correct answer.
  4. Runway 24 braking action is 0.60

Explanation

The R prefix denotes runway visual range, the runway designator identifies the runway, and the four-digit value is the RVR in metres. A four-digit group after the solidus is the touchdown-zone RVR, so 0600 means 600 m.

Question 28Aviation meteorology theory and weather interpretation

What is the standard lapse rate of temperature in the International Standard Atmosphere in the troposphere?

  1. 1.98 degrees Celsius per 1000 ft Correct answer.
  2. 2 degrees Celsius per 1000 ft
  3. 6.5 degrees Celsius per 1000 ft
  4. 0.65 degrees Celsius per 100 ft

Explanation

The ISA temperature lapse rate is 6.5 degrees Celsius per kilometre, which converts to approximately 1.98 degrees Celsius per 1000 ft. This value is used when calculating ISA deviation and density altitude.

Question 29Aviation meteorology theory and weather interpretation

Which cloud genus is composed of ice crystals and appears as thin, white, wispy streaks high in the troposphere?

  1. Altostratus
  2. Cirrus Correct answer.
  3. Stratocumulus
  4. Nimbostratus

Explanation

Cirrus clouds form at high levels where temperatures are well below freezing and consist almost entirely of ice crystals. They appear as detached, wispy, fibrous streaks and often signal an approaching warm front.

Question 30Aviation meteorology theory and weather interpretation

What does the term 'veering' mean when describing a change in wind direction?

  1. The wind direction changes in a clockwise sense Correct answer.
  2. The wind becomes gusty and variable
  3. The wind direction changes in an anticlockwise sense
  4. The wind speed increases steadily

Explanation

Veering describes a clockwise change in wind direction, for example from 270 to 300 degrees. Backing is the opposite, an anticlockwise change. The terms refer to direction only, not speed.

Question 31Aviation meteorology theory and weather interpretation

Which hazard is most associated with flying in the vicinity of a mature thunderstorm cell?

  1. A steady decrease in wind speed near the storm
  2. Severe turbulence, hail, and icing Correct answer.
  3. Improved visibility beneath the cloud base
  4. Smooth laminar airflow throughout the cloud

Explanation

Mature thunderstorms contain violent updraughts and downdraughts, large hail, and heavy icing, all of which are serious hazards. Pilots should give such cells a wide berth, particularly below the cloud base where downdraughts and microbursts occur.

Question 32Aviation meteorology theory and weather interpretation

What does the term 'gust' refer to in an aviation forecast?

  1. A temporary reduction in visibility below 1000 metres
  2. A change in wind direction of more than 30 degrees
  3. A brief peak in wind speed significantly above the mean wind Correct answer.
  4. A sustained increase in wind speed lasting several hours

Explanation

A gust is a short-lived fluctuation in wind speed that rises noticeably above the mean. In forecasts it is shown after the mean speed, for example 25015G30KT, indicating gusts to 30 knots.

Question 33Aviation meteorology theory and weather interpretation

Which pressure system is typically associated with subsiding air, clear skies, and light winds at the surface?

  1. An anticyclone Correct answer.
  2. A thermal low
  3. A frontal depression
  4. A tropical cyclone

Explanation

Anticyclones are regions of high pressure where air subsides, which suppresses cloud formation and generally produces fine weather. Surface winds are usually light and the weather is stable, though fog can form under the inversion.

Question 34Aviation meteorology theory and weather interpretation

An aircraft is flying at an indicated altitude of 5000 ft with the altimeter set to the local QNH. The outside air temperature is significantly colder than ISA at that level. How does the true altitude compare with the indicated altitude?

  1. True altitude is lower than indicated altitude Correct answer.
  2. True altitude is higher than indicated altitude
  3. True altitude depends only on the QNH value
  4. True altitude equals indicated altitude

Explanation

Cold air is denser, so pressure levels are compressed toward the surface. When the air is colder than ISA, the aircraft is lower than the altimeter indicates, which is a significant terrain-clearance hazard in mountainous areas.

Question 35Aviation meteorology theory and weather interpretation

A pilot observes altimeter reading 4500 ft with QNH 1000 hPa set. The aircraft flies into an area where the QNH is 1012 hPa without resetting the altimeter. What does the altimeter now indicate relative to the true altitude?

  1. It indicates the true altitude
  2. It indicates lower than the true altitude Correct answer.
  3. It indicates the true altitude only if temperature is standard
  4. It indicates higher than the true altitude

Explanation

Flying from lower to higher pressure without resetting the subscale means the altimeter over-reads the height above the new pressure datum, i.e. it indicates higher than the aircraft actually is. This is the classic 'high to low, look out below' hazard.

Question 36Aviation meteorology theory and weather interpretation

What is the primary cause of a sea breeze at a coastal aerodrome during a fine afternoon?

  1. Subsidence from an anticyclone over the sea
  2. The land heats more rapidly than the sea, causing air to rise over land and flow in from the sea Correct answer.
  3. A large-scale depression moving over the coast
  4. The sea heats more rapidly than the land, causing air to rise over the sea

Explanation

During the day, land warms faster than the adjacent sea, so air over land rises and cooler air flows inland from the sea. This produces a sea breeze, typically strongest in the afternoon and often causing a marked wind shift at coastal aerodromes.

Question 37Aviation meteorology theory and weather interpretation

What does the TAF change group 'TEMPO 1200/1400 3000 SHRA BKN010' indicate?

  1. Temporary fluctuations expected between 1200 and 1400 UTC Correct answer.
  2. A permanent change beginning at 1200 UTC
  3. Conditions will persist for the whole forecast period
  4. A probability of 30 percent for the whole period

Explanation

TEMPO indicates temporary fluctuations expected to last less than an hour at a time within the stated period. The group here forecasts temporary showers and reduced visibility and cloud base between 1200 and 1400 UTC.

Question 38Aviation meteorology theory and weather interpretation

Why does airframe icing most commonly occur in the temperature range between 0 and minus 20 degrees Celsius?

  1. Supercooled water droplets are most abundant in that range Correct answer.
  2. Ice crystals form only below minus 20 degrees Celsius
  3. Air density is highest in that range
  4. The aircraft surface is warmest in that range

Explanation

Clouds in the 0 to minus 20 degrees Celsius range frequently contain supercooled water droplets that freeze on impact with the airframe. Colder clouds tend to consist of ice crystals, which do not adhere readily.

Question 39Aviation meteorology theory and weather interpretation

A pilot reports severe turbulence while flying at low level over a mountain range with a strong cross-ridge wind. Which phenomenon is most likely responsible?

  1. Radiation fog
  2. A land breeze
  3. Mountain wave and rotor turbulence Correct answer.
  4. A sea breeze front

Explanation

Strong winds crossing a mountain ridge generate mountain waves and, beneath them, rotor turbulence on the lee side. This can produce severe turbulence at low levels, with associated downdraughts and hazardous conditions for light aircraft.

Question 40Aviation meteorology theory and weather interpretation

What is the significance of a METAR group 'BKN008'?

  1. Broken cloud with a top at 800 ft
  2. Broken cloud with 8 oktas coverage
  3. Broken cloud with a base at 800 ft above aerodrome level Correct answer.
  4. Broken cloud with a base at 8000 ft above aerodrome level

Explanation

BKN denotes broken cloud cover of five to seven oktas, and the three-digit figure is the height of the cloud base in hundreds of feet above aerodrome level. Thus BKN008 indicates a base of 800 ft.

Question 41Aviation meteorology theory and weather interpretation

Which condition would justify the issuance of an AIRMET rather than a SIGMET?

  1. A volcanic ash cloud
  2. A severe squall line with hail
  3. Moderate icing affecting light aircraft over a wide area Correct answer.
  4. Severe turbulence over a large area

Explanation

AIRMETs advise of moderate hazards such as moderate icing or moderate turbulence and extensive reduced visibility that may affect light aircraft. SIGMETs are reserved for severe or hazardous phenomena.

Question 42Aviation meteorology theory and weather interpretation

A pilot plans a VFR flight and the TAF includes 'PROB40 0600 FG'. What does this mean for planning?

  1. There is a 40 percent chance of 600 ft cloud base
  2. Fog will clear by 0600 UTC
  3. Fog is certain with visibility 600 m
  4. There is a 40 percent probability of fog and 600 m visibility in the forecast period Correct answer.

Explanation

PROB40 indicates a 40 percent probability of the following conditions occurring, which in this group are fog and visibility of 600 metres. Such a probability is a strong caution for VFR planning because conditions may fall below VFR minima.

Question 43Aviation meteorology theory and weather interpretation

In the Southern Hemisphere, how does the wind circulate around a high-pressure centre at the surface?

  1. Anticlockwise and inward
  2. Anticlockwise and outward
  3. Clockwise and inward
  4. Clockwise and outward Correct answer.

Explanation

In the Southern Hemisphere, Coriolis deflection is to the left, so surface flow around a high is anticlockwise in the Northern Hemisphere but clockwise and outward in the Southern Hemisphere. Friction causes the flow to cross the isobars outward from the centre of high pressure.

Question 44Aviation meteorology theory and weather interpretation

What weather is typically associated with the passage of a warm front in New Zealand?

  1. Severe thunderstorms and hail
  2. A sudden wind veer, heavy showers, and rapid clearing
  3. Clear skies and a rapid rise in pressure
  4. A gradual fall in cloud base, steady rain, and a rise in temperature Correct answer.

Explanation

Ahead of a warm front, cloud lowers progressively from cirrus to altostratus and then nimbostratus, with steady rain. After the front passes, temperature rises and the wind veers, with pressure levelling off.

Question 45Aviation meteorology theory and weather interpretation

What is the main reason that a temperature inversion can trap smoke and reduce visibility at an aerodrome?

  1. The inversion lowers the freezing level
  2. The inversion increases the dewpoint
  3. The inversion increases wind speed at the surface
  4. The inversion prevents vertical mixing, so pollutants remain in the surface layer Correct answer.

Explanation

An inversion is a layer where temperature increases with height, which suppresses vertical motion. Pollutants and moisture released near the surface cannot disperse upward, so smoke and haze accumulate and visibility falls.

Question 46Aviation meteorology theory and weather interpretation

A pilot on approach at an aerodrome with a QNH of 1005 hPa notes that the altimeter reads 2000 ft while the aerodrome elevation is 200 ft. What is the most likely explanation?

  1. The altimeter has been set to the standard pressure 1013 hPa
  2. The altimeter has been set to QFE
  3. The altimeter subscale is set too low
  4. The altimeter subscale is set too high Correct answer.

Explanation

If the subscale is set to a pressure higher than the actual QNH, the altimeter over-reads, showing a height greater than the true altitude. Here the reading far exceeds the aerodrome elevation, consistent with a subscale set too high.

Question 47Aviation meteorology theory and weather interpretation

Why does a tropical cyclone weaken rapidly after making landfall?

  1. Its wind speed increases due to surface heating
  2. It loses its warm ocean moisture source and gains surface friction Correct answer.
  3. Its central pressure deepens over land
  4. It gains energy from the land surface

Explanation

A tropical cyclone derives its energy from warm ocean water and the latent heat released by condensation. Once over land, it loses the moisture source and experiences increased friction, so it weakens rapidly.

Question 48Aviation meteorology theory and weather interpretation

A pilot is flying at 8000 ft with an OAT of minus 10 degrees Celsius in an atmosphere where the ISA temperature at that level is minus 1 degree Celsius. What is the ISA deviation and what does it imply for the true altitude?

  1. Plus 9 degrees Celsius, true altitude higher than indicated
  2. Minus 9 degrees Celsius, true altitude higher than indicated
  3. Minus 9 degrees Celsius, true altitude lower than indicated Correct answer.
  4. Plus 9 degrees Celsius, true altitude lower than indicated

Explanation

The ISA deviation is the OAT minus ISA temperature, i.e. minus 10 minus minus 1 equals minus 9 degrees Celsius. Colder-than-ISA air means pressure levels are compressed, so the aircraft's true altitude is lower than indicated.

Question 49Aviation meteorology theory and weather interpretation

A low-level jet is forecast overnight over an inland basin. What effect is most likely on the surface wind at an aerodrome in that basin?

  1. Surface winds strengthen to match the jet exactly
  2. Surface winds become calm and visibility improves
  3. Surface winds remain light while winds aloft strengthen Correct answer.
  4. Surface winds veer to a constant direction with no change in speed

Explanation

A nocturnal low-level jet forms above a surface inversion, and the stable layer decouples the surface from the stronger flow aloft. Surface winds may stay light while winds aloft increase, though shear and turbulence can occur near the top of the inversion.

Question 50Aviation meteorology theory and weather interpretation

In a region where the 500 hPa chart shows a deep trough and a strong jet streak, what weather is most likely at the surface?

  1. A steady anticyclone with light winds
  2. Enhanced uplift, cloud, and possible severe weather downstream of the trough Correct answer.
  3. Widespread subsidence and clear skies
  4. Persistent fog with no wind

Explanation

A deep upper trough is associated with rising motion and convergence, and a jet streak enhances divergence aloft. Together these support uplift, cloud development, and potentially severe weather, especially downstream of the trough axis.