### Q101: What does the wind barb symbol below represent? ^t50q101 ![[figures/t50_q101.png]] - 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. ### Q102: What is the name of the fog that develops when a moist air mass moves horizontally over a colder surface? ^t50q102 - A) Radiation fog - B) Orographic fog - C) Advection fog - D) Sea spray **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. ### Q103: Which typical Swiss weather pattern does the sketch below show? ^t50q103 ![[figures/t50_q103.png]] - 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. ### Q104: Which altimeter setting must you select so that the instrument shows your height above a specific aerodrome (AAL)? ^t50q104 - A) The QNH of the aerodrome. - B) The QFF of the aerodrome. - C) The QFE of the aerodrome. - D) The QNE of the aerodrome. **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. ### Q105: What are the wind speed and direction in this METAR? LFSB 171100Z 29004KT 220V340 9999 FEW043 28/17 Q1013 NOSIG= ^t50q105 - A) Wind from WNW, 4 knots, direction varying between SW and NNW. - B) Wind from ESE, 4 knots, direction varying between NE and SSE. - C) Wind from ESE, 4 knots, direction varying between SW and NNW. - D) Wind from WNW, 4 knots, direction varying between NE and SSE. **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. ### Q106: During summer in central Europe, what phenomenon is typical of an advancing cold front when the warm air ahead has an unstable thermodynamic structure? ^t50q106 - A) Stratiform cloud cover. - B) A rapid temperature rise after the front passes. - C) Thunderstorm clouds. - D) A rapid drop in atmospheric pressure after frontal passage. **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. ### Q107: Along the route from LOWK to EDDP (dotted arrow), what weather phenomena should be anticipated? ^t50q107 ![[figures/t50_q107.png]] - 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. ### Q108: Which type of cloud is most likely to cause heavy showers? ^t50q108 - A) Nimbostratus - B) Altostratus - C) Cirrocumulus - D) Cumulonimbus **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. ### Q109: A radiosonde at high altitude in the Northern Hemisphere has a low pressure area to its north and a high pressure area to its south. In which direction will the wind carry the balloon? ^t50q109 - A) North - B) West - C) East - D) South **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. ### Q110: When air is forced upward by terrain and encounters unstable, moist layers, what are the resulting thunderstorms called? ^t50q110 - A) Cold front thunderstorms - B) Orographic thunderstorms - C) Thermal thunderstorms - D) Warm front thunderstorms **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. ### Q111: Which set of conditions favours the development of advection fog? ^t50q111 - A) Cold, humid air flowing over a warm ocean - B) Moisture evaporating from warm, humid ground into cold air - C) Warm, humid air flowing over a cold surface - D) Warm, humid air cooling on a cloudy night **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. ### Q112: Which process leads to the formation of advection fog? ^t50q112 - A) Warm, moist air transported across cold ground areas - B) Cold, moist air mixed with warm, moist air - C) Lengthy radiation on cloud-free nights - D) Cold, moist air transported across warm ground areas **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. ### Q113: During the passage of a cold front, what pressure pattern is typically observed? ^t50q113 - A) A steady decrease in pressure - B) A brief decrease followed by an increase in pressure - C) A constant pressure pattern - D) A steady increase in pressure **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. ### Q114: Which frontal boundary separates subtropical air from polar cold air, particularly across Central Europe? ^t50q114 - A) Polar front - B) Cold front - C) Occlusion - D) Warm front **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. ### Q115: In Central Europe during summer, what weather conditions are typically associated with high pressure areas? ^t50q115 - A) Closely spaced isobars with calm winds, development of local wind systems - B) Widely spaced isobars with strong prevailing westerly winds - C) Widely spaced isobars with calm winds, development of local wind systems - D) Closely spaced isobars with strong prevailing northerly winds **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. ### Q116: What weather can be expected in high pressure areas during the winter season? ^t50q116 - A) Changing weather with frontal line passages - B) Light winds and extensive areas of high fog - C) Squall lines and thunderstorm activity - D) Calm weather with cloud dissipation, a few high Cu **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. ### Q117: At which temperature range is airframe icing most hazardous? ^t50q117 - A) +5° to -10° C - B) 0° to -12° C - C) +20° to -5° C - D) -20° to -40° C **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. ### Q118: When large, supercooled droplets strike the leading surfaces of an aircraft, which type of ice is produced? ^t50q118 - A) Clear ice - B) Mixed ice - C) Hoar frost - D) Rime ice **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. ### Q119: What conditions must be present for thermal thunderstorms to develop? ^t50q119 - A) Conditionally unstable atmosphere, elevated temperature and high humidity - B) Absolutely stable atmosphere, elevated temperature and low humidity - C) Absolutely stable atmosphere, elevated temperature and high humidity - D) Conditionally unstable atmosphere, low temperature and low humidity **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. ### Q120: During which stage of a thunderstorm do updrafts dominate? ^t50q120 - A) Mature stage - B) Upwind stage - C) Dissipating stage - D) Cumulus stage **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. ### Q121: Where should heavy downdrafts and strong wind shear near the ground be expected? ^t50q121 - A) During warm summer days with high, flattened Cu clouds. - B) Close to rainfall areas of intense showers or thunderstorms. - C) During an approach to a coastal airfield with a strong sea breeze. - D) On cold, clear nights when radiation fog is forming. **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. ### Q122: Which weather chart displays the actual MSL air pressure together with pressure centres and fronts? ^t50q122 - A) Hypsometric chart - B) Prognostic chart - C) Wind chart - D) Surface weather chart **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. ### Q123: What kind of information can be derived from satellite images? ^t50q123 - A) Turbulence and icing conditions - B) Temperature and dew point of surrounding air - C) An overview of cloud cover and frontal lines - D) Flight visibility, ground visibility, and ground contact **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. ### Q124: Which information is available in the ATIS but not in a METAR? ^t50q124 - A) Current weather details such as precipitation types - B) Approach data including ground visibility and cloud base - C) Operational details such as active runway and transition level - D) Mean wind speeds and maximum gust speeds **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. ### Q125: Which cloud type signals the presence of thermal updrafts? ^t50q125 - A) Lenticularis - B) Stratus - C) Cumulus - D) Cirrus **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. ### Q126: Compared to the dry adiabatic lapse rate, the saturated adiabatic lapse rate is... ^t50q126 - A) Equal to the dry adiabatic lapse rate. - B) Lower than the dry adiabatic lapse rate. - C) Higher than the dry adiabatic lapse rate. - D) Proportional to the dry adiabatic lapse rate. **Correct: B)** > **Explanation:** The saturated (moist) adiabatic lapse rate (SALR, averaging about 0.6°C/100 m) is lower than the dry adiabatic lapse rate (DALR, 1.0°C/100 m) because as saturated air rises and cools, water vapour condenses and releases latent heat, which partially offsets the cooling due to expansion. This means saturated air cools more slowly per unit of altitude gained. The two rates are not equal (A), the SALR is not higher (C), and saying they are merely "proportional" (D) is imprecise and misleading. ### Q127: What is the value of the dry adiabatic lapse rate? ^t50q127 - A) 0,6° C / 100 m. - B) 0,65° C / 100 m. - C) 1,0° C / 100 m. - D) 2° / 1000 ft. **Correct: C)** > **Explanation:** The dry adiabatic lapse rate (DALR) is exactly 1.0°C per 100 m (or approximately 3°C per 1000 ft). This is the rate at which an unsaturated air parcel cools when rising (or warms when descending) purely due to adiabatic expansion or compression. Option A (0.6°C/100 m) is approximately the saturated adiabatic lapse rate. Option B (0.65°C/100 m) is the standard atmosphere environmental lapse rate. Option D (2°/1000 ft) converts to about 0.66°C/100 m, which does not match the DALR. ### Q128: What weather should be expected when the atmosphere is conditionally unstable? ^t50q128 - A) Cloud-free skies, sunshine, light winds - B) Layered clouds reaching high levels, prolonged rain or snow - C) Towering cumulus, isolated rain showers or thunderstorms - D) Shallow cumulus clouds with bases at medium levels **Correct: C)** > **Explanation:** Conditional instability means the atmosphere is stable for unsaturated air but becomes unstable once air parcels are lifted to saturation. When triggered — by surface heating, orographic lift, or frontal forcing — this instability produces vigorous convection: towering cumulus and cumulonimbus clouds with isolated showers and thunderstorms. Clear skies (A) indicate absolute stability or dry conditions. Layered clouds with prolonged rain (B) characterise absolutely stable (stratiform) weather. Shallow mid-level cumulus (D) indicates limited instability insufficient for significant vertical development. ### Q129: Identify the cloud type shown in the picture. See figure (MET-004). Siehe Anlage 3 ^t50q129 - A) Stratus - B) Cumulus - C) Cirrus - D) Altocumulus **Correct: C)** > **Explanation:** The figure MET-004 shows thin, wispy, high-altitude clouds with a delicate fibrous or streaky structure — the defining visual characteristics of cirrus clouds. Cirrus forms above approximately 6,000 m (FL200) and consists entirely of ice crystals, which produce its distinctive silky or hair-like appearance. Stratus (A) is a grey, featureless layer cloud at low altitude. Cumulus (B) has a well-defined, puffy vertical structure. Altocumulus (D) appears as white or grey patches or layers of rounded masses at mid-level. ### Q130: What is required for the development of medium to large precipitation particles? ^t50q130 - A) An inversion layer. - B) A high cloud base. - C) Strong updrafts. - D) Strong wind. **Correct: C)** > **Explanation:** Medium to large precipitation particles (raindrops, hailstones) need time to grow by collision-coalescence or the Bergeron ice-crystal process, and strong updrafts keep droplets and ice crystals suspended in the cloud long enough for this growth to occur. Without sufficient updraft strength, particles fall out before reaching significant size. An inversion layer (A) suppresses cloud growth and precipitation. A high cloud base (B) reduces available cloud depth for particle growth. Strong horizontal wind (D) does not contribute to the vertical suspension needed for particle growth. ### Q131: On the weather chart, the symbol labelled (2) represents a / an... See figure (MET-005) Siehe Anlage 4 ^t50q131 - A) Cold front. - B) Warm front. - C) Front aloft. - D) Occlusion. **Correct: B)** > **Explanation:** On standard synoptic weather charts, a warm front is depicted as a line with semicircles pointing in the direction of movement (into the colder air mass). The referenced figure MET-005 shows symbol (2) matching this convention — semicircles on one side of the frontal line. A cold front (A) uses triangular barbs pointing in the direction of advance. An occlusion (D) uses alternating triangles and semicircles on the same side. A front aloft (C) is marked with a different symbology indicating the front does not reach the surface. ### Q132: Within the warm sector of a polar front low during summer, what visual flight conditions are typical? ^t50q132 - A) Visibility below 1000 m, cloud covering the ground - B) Good visibility, a few isolated high clouds - C) Moderate to good visibility, scattered clouds - D) Moderate visibility, heavy showers and thunderstorms **Correct: C)** > **Explanation:** The warm sector lies between the warm front and the cold front, containing the warmest, most homogeneous air. During summer, this air mass typically offers moderate to good visibility with scattered or broken cloud layers — flyable VFR conditions. Visibility below 1000 m with ground-covering cloud (A) is more typical of winter fog or orographic stratus. Heavy showers and thunderstorms (D) are characteristic of the cold front itself, not the warm sector. Few isolated high clouds (B) describe pre-frontal conditions well ahead of the system. ### Q133: After a cold front has passed, what visual flight conditions are typical? ^t50q133 - A) Moderate visibility with lowering cloud bases, onset of prolonged precipitation - B) Good visibility, cumulus cloud development with rain or snow showers - C) Scattered cloud layers, visibility over 5 km, shallow cumulus clouds forming - D) Poor visibility, overcast or ground-covering stratus, snow **Correct: B)** > **Explanation:** After a cold front passes, cold, clean polar air replaces the warm sector. This unstable air mass produces excellent visibility between showers, with convective cumulus clouds developing from surface heating and occasional rain or snow showers from cumulus congestus. Option A describes warm front approach conditions (lowering bases, continuous rain). Option C understates the convective activity typical of post-frontal polar air. Option D describes poor visibility with stratus, which is more typical of the cold sector of a warm occlusion, not the fresh polar air behind a cold front. ### Q134: In what direction does a polar front low typically move? ^t50q134 - A) Parallel to the warm front line toward the south - B) Northeastward in winter, southeastward in summer - C) Northwestward in winter, southwestward in summer - D) Parallel to the warm-sector isobars **Correct: D)** > **Explanation:** A polar front low (extratropical cyclone) is steered by the upper-level airflow, which is closely approximated by the direction of the isobars in the warm sector — the warm sector wind effectively carries the entire system along. This is a more reliable steering rule than fixed seasonal directions. Option A wrongly states southward movement. Options B and C propose rigid seasonal rules that oversimplify the highly variable tracks of mid-latitude cyclones across Europe. ### Q135: What is the characteristic pressure pattern as a polar front low passes over? ^t50q135 - A) Falling pressure ahead of the warm front, steady pressure in the warm sector, rising pressure behind the cold front - B) Rising pressure ahead of the warm front, steady pressure in the warm sector, rising pressure behind the cold front - C) Falling pressure ahead of the warm front, steady pressure in the warm sector, falling pressure behind the cold front - D) Rising pressure ahead of the warm front, rising pressure in the warm sector, falling pressure behind the cold front **Correct: A)** > **Explanation:** The classic pressure trace of a passing polar front low follows three phases: pressure falls as the warm front approaches (the low draws nearer), pressure holds relatively steady in the warm sector between the two fronts, and pressure rises sharply after the cold front passes as cold, dense air replaces the warm sector. Option B wrongly has pressure rising ahead of the warm front. Option C has pressure falling behind the cold front, contradicting the arrival of dense cold air. Option D reverses the entire pattern. ### Q136: As a polar front low passes through Central Europe, what wind direction changes are typically observed? ^t50q136 - A) Backing at both the warm front and the cold front - B) Veering at the warm front, backing at the cold front - C) Backing at the warm front, veering at the cold front - D) Veering at both the warm front and the cold front **Correct: D)** > **Explanation:** In the Northern Hemisphere, as a typical polar front low passes, wind veers (shifts clockwise) at both frontal passages. At the warm front, wind veers from southeast to south or southwest. At the cold front, it veers again from southwest to west or northwest. This consistent clockwise shift indicates the low is passing to the north of the observer, which is the normal track for lows crossing Central Europe. Backing (A, B, C) would indicate the low passing to the south — an uncommon trajectory. ### Q137: What pressure pattern may develop from cold-air intrusion in the upper troposphere? ^t50q137 - A) Development of a low in the upper troposphere - B) Development of a high in the upper troposphere - C) Oscillating pressure - D) Development of a large surface low **Correct: A)** > **Explanation:** When cold air intrudes into the upper troposphere, it reduces the thickness of the atmospheric column (cold air is denser and occupies less vertical space), causing the heights of upper pressure surfaces to drop. This creates an upper-level low or trough. These cold-pool lows aloft are potent triggers for convective instability and often initiate cyclogenesis at the surface. An upper high (B) would form from warm-air advection, not cold intrusion. Oscillating pressure (C) and a large surface low (D) are not the direct or primary consequence of upper-level cold intrusion. ### Q138: Cold air flowing into the upper troposphere may lead to... ^t50q138 - A) Stabilisation and settled weather. - B) Frontal weather systems. - C) Showers and thunderstorms. - D) Calm weather and cloud dissipation. **Correct: C)** > **Explanation:** Cold air advecting into the upper troposphere steepens the lapse rate (cold air aloft over relatively warmer air below), producing conditional or even absolute instability. This destabilisation triggers convection, generating showers and thunderstorms — especially when combined with surface moisture and daytime heating. Stabilisation and settled weather (A) and calm conditions (D) are the opposite of what cold upper-air intrusion produces. Frontal weather (B) requires surface air-mass boundaries, which are not a direct result of upper-tropospheric cooling. ### Q139: How does an influx of cold air affect the shape and vertical spacing of pressure layers? ^t50q139 - A) Increased vertical spacing, raising of heights (high pressure) - B) Decreased vertical spacing, raising of heights (high pressure) - C) Increased vertical spacing, lowering of heights (low pressure) - D) Decreased vertical spacing, lowering of heights (low pressure) **Correct: D)** > **Explanation:** Cold air is denser than warm air, so a cold air column has less vertical distance (decreased spacing) between any two pressure surfaces. Because the column is compressed, the upper pressure surfaces lie at lower geometric heights, which is identified as low pressure aloft on hypsometric charts. This is why upper-level lows are always associated with cold-core air masses. Warm air produces the opposite: increased spacing and raised heights (high pressure aloft), as described in options A and C. ### Q140: During summer, what weather is typical of high pressure areas? ^t50q140 - A) Squall lines and thunderstorm activity - B) Settled weather with cloud dissipation, a few high Cu - C) Changeable weather with frontal passages - D) Light winds with widespread high fog **Correct: B)** > **Explanation:** In summer, anticyclones bring subsiding air that warms adiabatically, suppressing deep convection and producing clear to partly cloudy skies with perhaps a few fair-weather cumulus (Cu humilis) from daytime thermal heating. The overall character is settled, warm, and dry. Squall lines and thunderstorms (A) require convective instability not present in a well-established high. Frontal passages (C) are features of low-pressure troughs. Widespread high fog (D) is a winter high-pressure phenomenon caused by temperature inversions trapping cold moist air. ### Q141: On the windward side of a mountain range during Foehn conditions, what weather should be expected? ^t50q141 - A) Scattered cumulus clouds accompanied by showers and thunderstorms - B) Light wind with formation of high stratus (high fog) - C) Layered clouds, mountains obscured, poor visibility, moderate to heavy rain - D) Cloud dissipation with unusual warming, strong gusty winds **Correct: C)** > **Explanation:** On the windward (Stau) side during Foehn, moist air is forced to rise over the mountain barrier, cooling adiabatically and producing dense layered clouds (stratus, nimbostratus), obscured mountain peaks, poor visibility, and moderate to heavy orographic precipitation. Option D describes the lee-side Foehn effect — warm, dry, gusty descending wind — which is the opposite side of the mountains. Option A describes convective (unstable) weather, not the organised forced ascent of a Foehn pattern. Option B describes stagnant anticyclonic conditions, not active orographic lifting. ### Q142: Which chart depicts areas of precipitation? ^t50q142 - A) Wind chart - B) Radar picture - C) GAFOR - D) Satellite picture **Correct: B)** > **Explanation:** Weather radar detects precipitation directly by measuring the intensity of microwave energy backscattered from raindrops, snowflakes, and hail. Radar imagery shows the precise location, extent, and intensity of precipitation areas in near-real-time. A satellite picture (D) shows cloud cover but cannot directly distinguish precipitating from non-precipitating clouds. A wind chart (A) displays wind patterns only. A GAFOR (C) is a coded route forecast for general aviation that categorises flying conditions but does not depict precipitation areas graphically. ### Q143: An inversion is an atmospheric layer where... ^t50q143 - A) Pressure increases with increasing height. - B) Temperature remains constant with increasing height. - C) Temperature decreases with increasing height. - D) Temperature increases with increasing height. **Correct: D)** > **Explanation:** An inversion is a layer of the atmosphere where temperature increases with altitude, which is the reverse ("inversion") of the normal tropospheric lapse rate. Inversions are extremely stable and act as lids that suppress convection, trap pollution, and limit thermal development for glider pilots. Option B describes an isothermal layer (constant temperature). Option C describes the normal lapse rate. Option A is incorrect because atmospheric pressure always decreases with height, regardless of the temperature profile. ### Q144: Which condition may prevent radiation fog from forming? ^t50q144 - A) A clear, cloudless night - B) Low temperature-dew point spread - C) Overcast cloud cover - D) Calm wind conditions **Correct: C)** > **Explanation:** Radiation fog requires the ground to radiate longwave heat to space, cooling the surface air to the dew point. An overcast cloud layer acts as a blanket, absorbing and re-emitting radiation back toward the ground, preventing the surface from cooling sufficiently. Therefore, overcast cloud cover prevents radiation fog formation. A clear night (A), low spread (B), and calm wind (D) all favour fog formation — they are prerequisites, not preventative conditions. ### Q145: On the chart, the symbol labelled (3) represents a / an... See figure (MET-005) Siehe Anlage 4 ^t50q145 - A) Warm front. - B) Cold front. - C) Occlusion. - D) Front aloft. **Correct: C)** > **Explanation:** An occluded front is depicted on synoptic charts by a line combining both the cold front triangles and the warm front semicircles on the same side, representing the merger of the two fronts when the faster-moving cold front overtakes the warm front. Symbol (3) in figure MET-005 shows this combined symbology, identifying it as an occlusion. A warm front (A) uses only semicircles. A cold front (B) uses only triangles. A front aloft (D) has a distinct marking indicating the frontal surface does not reach the ground. ### Q146: A boundary between a cold polar air mass and a warm subtropical air mass that shows no horizontal movement is known as a... ^t50q146 - A) Warm front. - B) Occluded front. - C) Stationary front. - D) Cold front. **Correct: C)** > **Explanation:** A stationary front is a boundary between two contrasting air masses — here polar and subtropical — that is not moving significantly in either direction. Neither the cold air nor the warm air is advancing. A cold front (D) is specifically an advancing cold air mass pushing warm air aside. A warm front (A) is advancing warm air overriding cold air. An occluded front (B) results from a cold front overtaking a warm front within a mature cyclone — it involves merging fronts, not stationary boundaries. ### Q147: Which situation may lead to severe wind shear? ^t50q147 - A) Cross-country flying beneath Cu clouds at roughly 4 octas coverage - B) A shower visible in the vicinity of the airfield - C) Final approach 30 minutes after a heavy shower has cleared the airfield - D) Flying ahead of a warm front with Ci clouds visible **Correct: B)** > **Explanation:** An active shower near an airfield indicates ongoing convective downdrafts and outflow boundaries that create severe, rapidly changing low-level wind shear — a critical hazard during takeoff and landing. The gust front from a nearby shower can change wind direction and speed dramatically within seconds. Cross-country flying below moderate Cu (A) involves normal soaring conditions. Thirty minutes after a shower (C), conditions have typically stabilised. Cirrus ahead of a warm front (D) is an upper-level indicator without immediate low-level shear implications. ### Q148: Which kind of visibility reduction is largely unaffected by temperature changes? ^t50q148 - A) Mist (BR) - B) Patches of fog (BCFG) - C) Haze (HZ) - D) Radiation fog (FG) **Correct: C)** > **Explanation:** Haze (HZ) is caused by dry particulates — dust, smoke, industrial pollution, and fine sand — suspended in the atmosphere. Because these particles are not moisture-dependent, haze persists regardless of temperature changes. Mist (A), fog patches (B), and radiation fog (D) are all formed by water droplet suspension and are highly sensitive to temperature: warming evaporates the droplets and improves visibility, while cooling promotes further condensation and worsens it. ### Q149: In a METAR, how are moderate showers of rain encoded? ^t50q149 - A) TS. - B) .+RA. - C) SHRA. - D) .+TSRA **Correct: C)** > **Explanation:** In METAR format, the descriptor "SH" (shower) is combined with the precipitation type "RA" (rain) to form "SHRA," which denotes moderate showers of rain. No intensity prefix means moderate. "+RA" (B) indicates heavy continuous rain, not a shower. "TS" (A) denotes a thunderstorm without specifying precipitation type. "+TSRA" (D) indicates a heavy thunderstorm with rain — a more severe phenomenon than a simple rain shower. ### Q150: For which areas are SIGMET warnings issued? ^t50q150 - A) Airports. - B) FIRs / UIRs. - C) Specific routings. - D) Countries. **Correct: B)** > **Explanation:** SIGMET (Significant Meteorological Information) warnings are issued for Flight Information Regions (FIRs) and Upper Information Regions (UIRs), which are standardised ICAO airspace blocks managed by specific ATC authorities. They warn of hazardous weather phenomena (severe turbulence, icing, volcanic ash, thunderstorms) within these defined airspace volumes. SIGMETs are not issued for individual airports (A) — those use AIRMETs or aerodrome warnings. They are not route-specific (C) or country-specific (D), as a single country may contain multiple FIRs.