ATPL Meteorology study guide
ATPL Meteorology · Work through your exam, one topic at a time.
Meteorology is one of the core theoretical knowledge subjects in the Airline Transport Pilot Licence (ATPL) examination. The credential is intended for pilots progressing toward the privileges of an airline transport pilot licence, and the meteorology paper tests whether a candidate can interpret atmospheric behaviour well enough to make sound operational decisions, not merely recall definitions. The ATPL Meteorology study guide has 10 sections and about 3,105 words.
01The Atmosphere: Composition, Structure and Standard Atmosphere
Know the dry-air mix by volume: roughly 78% nitrogen, 21% oxygen, and about 1% argon plus trace gases. Water vapour is variable (0-4%) and matters far more than its share suggests, because it drives latent heat release, cloud formation and density changes.
354 words, about 2 min02Temperature, Pressure, Density and Their Altimetry Implications
Temperature, pressure and density are linked by the gas law: at constant pressure, warmer air is less dense, and at constant temperature, higher pressure means denser air. Density altitude is the single most examined idea: it is pressure altitude corrected for temperature.
306 words, about 2 min03Atmospheric Moisture, Humidity and Phase Changes
Understand the vocabulary precisely. Absolute humidity is mass of vapour per unit volume.
321 words, about 2 min04Stability, Instability and Lapse Rates
Stability is decided by comparing the environmental lapse rate (ELR) with the dry adiabatic lapse rate (DALR, ~3°C/1000 ft) and saturated adiabatic lapse rate (SALR, ~1.5°C/1000 ft). If the ELR is less than the SALR, the air is absolutely stable: a displaced parcel returns.
289 words, about 1 min05Clouds, Fog and Precipitation
Clouds are grouped by height and shape. High clouds (cirrus, cirrostratus, cirrocumulus) are ice; medium clouds (altostratus, altocumulus) are mixed; low clouds (stratus, stratocumulus, nimbostratus) are water droplets and may contain supercooled water.
310 words, about 2 min06Air Masses, Fronts and Frontal Weather
Air masses take the character of their source region: polar or tropical for temperature, maritime or continental for moisture. Know the four main types and their typical weather.
325 words, about 2 min07Pressure Systems, Winds and Local Circulations
Wind blows from high to low pressure, deflected to the right in the northern hemisphere (left in the southern) by the Coriolis effect. Geostrophic wind flows parallel to straight isobars; gradient wind accounts for curvature.
277 words, about 1 min08Turbulence, Icing, Thunderstorms and Other Aviation Hazards
Turbulence types include mechanical (terrain, buildings), thermal (convection), frontal and clear-air turbulence (CAT), which occurs near jet streams and is invisible. Low-level wind shear and microbursts are the most dangerous near the ground: a sudden headwind-to-tailwind change during approach can cause a severe performance loss.
302 words, about 2 min09Meteorological Observations, Reports and Forecasts (METAR, TAF, SIGMET, Charts)
Know the METAR and TAF formats cold: wind direction and speed with gusts, visibility, runway visual range, present weather, cloud amount and base, temperature and dew point, QNH, and trend or validity. Cloud amounts: FEW (1-2 oktas), SCT (3-4), BKN (5-7), OVC (8).
310 words, about 2 min10Climatology, Seasonal Weather and Flight Planning Meteorology
Know the general circulation: the equatorial trough with the intertropical convergence zone (ITCZ), the subtropical highs with descending air and deserts, the mid-latitude westerlies with travelling depressions, and the polar highs. The ITCZ migrates seasonally, bringing the wet season to the tropics.
311 words, about 2 min