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- A) Wind from NNE, 120 kt
- B) Wind from NNE, 70 kt
- C) Wind from SSW, 70 kt
- D) Wind from SSW, 120 kt
Correct: C)
Explanation: Wind barbs point in the direction the wind blows from, with speed indicated by barbs and pennants on the upwind end: a pennant = 50 kt, a long barb = 10 kt, a short barb = 5 kt. The symbol shows a wind from SSW with one pennant (50 kt) and two long barbs (20 kt), totalling 70 kt. Options A and B incorrectly identify the direction as NNE — wind barbs point FROM the wind source, not toward it. Option D overstates the speed to 120 kt.
Correct: C)
Explanation: Advection fog forms when warm, moist air is transported (advected) horizontally over a colder surface, cooling from below until it reaches its dew point and condensation occurs at ground level. Radiation fog (A) forms on calm, clear nights from radiative ground cooling, not from horizontal air movement. Orographic fog (B) results from moist air being lifted over terrain. Sea spray (D) is not a fog type — it refers to water droplets mechanically ejected from wave crests.
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- A) Westerly wind situation
- B) Bise situation
- C) South Foehn situation
- D) North Foehn situation
Correct: C)
Explanation: The sketch depicts a South Foehn (Südföhn) situation, where a pressure gradient drives moist air from the south against the southern slopes of the Alps. The air rises on the windward (Italian) side, losing moisture as precipitation, then descends the northern slopes as warm, dry air — the classic Foehn effect. Option A (westerly wind) involves Atlantic air masses from the west. Option B (Bise) is a cold northeast wind. Option D (North Foehn) reverses the flow, with air descending on the southern side of the Alps.
Correct: C)
Explanation: QFE is the atmospheric pressure measured at the aerodrome reference point. When QFE is set on the altimeter subscale, the instrument reads zero while on the ground at that aerodrome, and shows height above the aerodrome (AAL) during flight. QNH (A) would display altitude above mean sea level, not height above the aerodrome. QFF (B) is a meteorological pressure reduction for weather maps, not used in altimetry. QNE (D) is the standard pressure setting (1013.25 hPa) for flight level indication.
Correct: A)
Explanation: In the METAR group "29004KT 220V340": 290 is the wind direction in degrees (290° = WNW), 04 is the speed in knots, and "220V340" indicates the direction varies between 220° (SW) and 340° (NNW). Options B and C incorrectly interpret 290° as ESE — that would be approximately 110°–120°. Option D has the correct mean direction (WNW) but reverses the variability range to NE and SSE, which contradicts the 220V340 notation.
Correct: C)
Explanation: When an advancing cold front encounters warm, unstable air ahead of it in a European summer setting, the forced lifting triggers vigorous convection and the rapid vertical development of cumulonimbus (thunderstorm) clouds with heavy precipitation, lightning, and gusty winds. Stratiform clouds (A) are associated with stable air masses. Temperature falls, not rises (B), after a cold front passes. Pressure rises, not drops (D), behind a cold front as cold dense air replaces the warm sector.
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- A) Gradual temperature increase, tailwind, isolated thunderstorms.
- B) Gradual temperature decrease, headwind, isolated thunderstorms.
- C) Gradual temperature increase, headwind, no thunderstorms.
- D) Gradual temperature decrease, tailwind, isolated thunderstorms.
Correct: B)
Explanation: Flying from LOWK (Klagenfurt, Austria) northward to EDDP (Leipzig, Germany), the aircraft moves into cooler air at higher latitudes, producing a gradual temperature decrease. The synoptic pattern on the chart indicates headwind conditions along this route and convective activity yielding isolated thunderstorms, particularly during summer. Option A wrongly predicts warming (heading north) and tailwind. Option C denies thunderstorm risk despite the synoptic instability shown. Option D correctly predicts cooling and thunderstorms but wrongly identifies a tailwind.
Correct: D)
Explanation: Cumulonimbus (Cb) clouds are massive convective clouds extending from near the surface to the tropopause, containing enormous quantities of water and ice sustained by powerful updrafts. They produce the heaviest showers, hail, and thunderstorms. Nimbostratus (A) produces prolonged, steady precipitation but not heavy showers. Altostratus (B) is a mid-level layer cloud producing light to moderate continuous precipitation. Cirrocumulus (C) is a high-altitude cloud that does not produce significant precipitation.
Correct: B)
Explanation: At high altitude, the wind is approximately geostrophic, blowing parallel to the isobars with low pressure to the left and high pressure to the right in the Northern Hemisphere. With low pressure to the north and high to the south, the pressure gradient force points northward, and the Coriolis deflection turns the resulting wind to the right — producing a westward (east-to-west) flow. The balloon is therefore carried toward the west. Options A, C, and D misapply the Buys-Ballot law for this pressure configuration.
Correct: B)
Explanation: When terrain (mountains, ridges, or hills) mechanically forces air upward and this lifted air encounters moist, unstable layers aloft, the resulting convective storms are classified as orographic thunderstorms. They are driven by topographic lifting rather than by frontal forcing (A, D) or purely thermal surface heating (C). Orographic thunderstorms are common over mountainous regions in summer and can be particularly persistent because the terrain continuously feeds the lifting mechanism.
Correct: C)
Explanation: Advection fog forms when warm, moist air moves horizontally over a colder surface and is cooled from below to its dew point. This commonly occurs when maritime tropical air flows over cold ocean currents or cold land in early spring. Cold air over warm water (A) would produce steam fog (evaporation fog), not advection fog. Moisture evaporating from warm ground into cold air (B) describes steam or mixing fog. Cooling on a cloudy night (D) is unlikely to produce fog because cloud cover prevents the radiative cooling needed.
Correct: A)
Explanation: Advection fog results from the horizontal transport (advection) of warm, moist air across a cold surface. The cold surface cools the air from below until it reaches its dew point, causing condensation at ground level. Option B describes mixing fog, where two air masses of different temperatures combine. Option C describes radiation fog, formed by nocturnal radiative cooling on clear, calm nights. Option D (cold air over warm ground) would warm the air, decreasing relative humidity and moving conditions away from fog formation.
Correct: B)
Explanation: As a cold front approaches, pressure falls ahead of it due to the pre-frontal trough. At the moment of frontal passage, pressure reaches its minimum, and immediately afterward it begins to rise sharply as cold, dense air moves in behind the front. This characteristic "V-shaped" pressure trace — a brief fall followed by a sustained rise — is the textbook pressure signature of cold front passage. Options A and D describe monotonic trends, while option C suggests no dynamic weather activity, none of which match frontal passage behaviour.
Correct: A)
Explanation: The polar front is the semi-permanent, quasi-continuous boundary zone separating warm subtropical air masses from cold polar air masses across the mid-latitudes, including Central Europe. It is the birthplace of extratropical cyclones. A cold front (B) is the leading edge of a single advancing cold air mass within a cyclone. A warm front (D) is the leading edge of advancing warm air. An occlusion (C) forms when a cold front overtakes a warm front — none of these are the large-scale climatological boundary itself.
Correct: C)
Explanation: Summer high-pressure areas over Central Europe produce widely spaced isobars, indicating weak synoptic-scale pressure gradients and therefore light prevailing winds. In the absence of strong gradient winds, locally driven thermal circulations — valley breezes, sea breezes, slope winds — develop and dominate the airflow pattern. Option A contradicts itself (close isobars do not produce calm winds). Option B describes strong westerlies associated with low-pressure systems. Option D describes a cold northerly flow pattern, not typical of summer anticyclones.
Correct: B)
Explanation: In winter, high-pressure areas produce subsidence inversions that trap cold, moist air near the surface, creating widespread high fog (Hochnebel) and stratus layers, particularly in valley and basin locations across Central Europe. Winds are light due to the weak pressure gradient. Option A (frontal weather) is associated with low-pressure systems. Option C (squall lines and thunderstorms) requires convective instability absent in winter highs. Option D describes summer high-pressure conditions with thermal cumulus development, not the foggy, grey winter anticyclone.
Correct: B)
Explanation: The most dangerous airframe icing occurs between 0°C and -12°C because supercooled liquid water droplets are most abundant and largest in this temperature band. These droplets freeze on contact with aircraft surfaces, producing heavy ice accumulation. Below -20°C (D), most cloud water has already frozen into ice crystals that bounce off rather than adhering. The range +5° to -10°C (A) extends into above-freezing temperatures where icing cannot occur. The range +20° to -5°C (C) is far too broad and mostly above freezing.
Correct: A)
Explanation: Clear ice (also called glaze ice) forms when large supercooled water droplets strike an aircraft surface and flow back along it before freezing, creating a smooth, dense, transparent, and very heavy ice layer that closely conforms to the surface shape. It is the most dangerous type of airframe ice because it is difficult to detect and remove. Rime ice (D) forms from small droplets that freeze instantly on contact, trapping air and creating a rough, white, opaque deposit. Mixed ice (B) is a combination of both. Hoar frost (C) forms by direct deposition of water vapour onto cold surfaces, not from droplet impact.
Correct: A)
Explanation: Thermal thunderstorms require three ingredients working together: a conditionally unstable atmosphere (one that becomes fully unstable once air parcels reach saturation and the level of free convection), elevated surface temperatures to trigger strong thermals, and high humidity to supply the moisture and latent heat energy that fuels deep convection. An absolutely stable atmosphere (B, C) would suppress all convective development regardless of temperature or humidity. Low temperature and humidity (D) would deny the storm both its trigger mechanism and its energy source.
Correct: D)
Explanation: The cumulus (initial/developing) stage of a thunderstorm is characterised exclusively by updrafts that build the cloud vertically from cumulus congestus toward cumulonimbus. No downdrafts or precipitation have yet developed. The mature stage (A) features coexisting updrafts and downdrafts along with precipitation, turbulence, and lightning. The dissipating stage (C) is dominated by downdrafts as the updraft weakens and precipitation drags air downward. "Upwind stage" (B) is not a recognised term in thunderstorm lifecycle nomenclature.
Correct: B)
Explanation: Intense showers and thunderstorms produce powerful downdrafts (microbursts and downbursts) driven by precipitation drag and evaporative cooling. When these downdrafts hit the ground they spread outward, generating dangerous low-level wind shear that can cause sudden airspeed loss on approach. Sea-breeze fronts (C) produce mild convergence, not heavy downdrafts. Radiation fog nights (D) are calm with virtually no wind shear. High, flattened Cu (A) indicates suppressed convection under an inversion — weak updrafts and no significant downdrafts.
Correct: D)
Explanation: The surface weather chart (synoptic analysis chart) depicts observed mean sea-level pressure using isobars, identifies pressure centres (highs and lows) with their central pressures, and plots the positions of fronts (warm, cold, occluded, stationary) based on actual observations. A prognostic chart (B) shows forecast conditions, not current observations. A wind chart (C) displays wind vectors only. A hypsometric chart (A) shows the height of constant-pressure surfaces aloft, not MSL pressure or surface fronts.
Correct: C)
Explanation: Satellite images (visible, infrared, and water vapour channels) provide a synoptic overview of cloud cover distribution, cloud type estimation, and the identification of frontal lines by recognising characteristic cloud patterns. Turbulence and icing (A) cannot be directly measured by satellite — those require pilot reports or forecast models. Temperature and dew point (B) are measured by radiosondes and surface stations. Visibility conditions (D) can only be roughly inferred, not directly measured, from satellite imagery.
Correct: C)
Explanation: ATIS (Automatic Terminal Information Service) broadcasts include operational aerodrome information such as the active runway, transition level, approach type in use, and relevant NOTAMs — none of which are encoded in a METAR. A METAR already contains precipitation types (A), visibility and cloud information (B), and wind speed including gusts (D). ATIS supplements the METAR with the operational data pilots need for arrival and departure.
Correct: C)
Explanation: Cumulus clouds are the visible markers of thermal convection: warm air rises from the surface, cools adiabatically to the dew point, and condenses, forming the flat-based, cauliflower-topped cloud that glider pilots use to locate thermals. Stratus (B) forms from broad, gentle lifting in stable air, not from thermals. Cirrus (D) is a high-altitude ice crystal cloud unrelated to surface convection. Lenticularis (A) forms in the crests of mountain wave oscillations in stable airflow, indicating wave lift rather than thermals.
