IR Skill test questions: Meteorology questions to expect during Instrument rating skill test

Examiner will ask you questions about IR-related meteorology

During the instrument rating skill test, the EASA examiner will ask you several IFR-related questions. The following elements may be used by the EASA IRE examiner for the Exam candidate’s verbal demonstration of theoretical knowledge.

Meteorology

(1) describe qualitatively and quantitatively the temperature lapse rates of the troposphere (mean value of 0.65 °C/100 m or 2 °C/1 000 ft and actual values);
(2) explain the characteristics of inversions and of an isothermal layer;
(3) explain the cooling and warming of the air on the earth or sea surfaces;
(4) describe qualitatively the influence of the clouds on the cooling and warming of the earth or sea surfaces as well as of the air near those surfaces;
(5) explain the influence of the wind on the cooling and warming of the air near the earth or sea surfaces;
(6) define ‘atmospheric pressure’;
(7) list the units of measurement of atmospheric pressure used in aviation (hPa, in.);
(8) describe isobars on the surface weather charts;
(9) explain the pressure variation with height;
(10) describe qualitatively the variation of the barometric lapse rate (note: the average value for the barometric lapse rate near mean sea level is 27 ft (8 m) per 1 hPa, whereas at about 5 500 m above mean sea level (AMSL) is 50 ft (15 m) per 1 hPa;
(11) describe and interpret contour lines (isohypses) on a constant pressure chart;
(12) describe the relationship between pressure, temperature, and density;
(13) describe the vertical variation of the air density in the atmosphere;
(14) describe the effect of humidity changes on the air density;
(15) explain the use of standardised values for the international standard atmosphere (ISA);
(16) list the main values of ISA (mean sea level pressure, mean sea level temperature, a vertical temperature lapse rate up to 20 km, as well as height and temperature of the tropopause);
(17) calculate the standard temperature in Celsius degrees for a given FL;
(18) determine a standard temperature deviation based on the difference between the given OAT and the standard temperature;
(19) define the following terms and acronyms and explain how they are related to each other: H, A, pressure A, FL, pressure level, true A, true H, elevation, QNH, QFE, and standard altimeter setting;
(20) describe the following terms: transition A, transition level, transition layer, terrain clearance, and lowest usable FL;
(21) calculate the different readings on the altimeter when the pilot changes the altimeter setting;
(22) illustrate with a numbered example the changes of the altimeter setting and the associated changes in reading when the pilot climbs through the transition altitude or descends through the transition level;
(23) derive the reading of the altimeter of an aircraft on the ground when the pilot uses different settings;
(24) explain the influence of the air temperature on the distance between the ground and the level reading on the altimeter as well as between two FLs;
(25) explain the influence of pressure areas on the true altitude;
(26) determine the true A/H for a given A/H and a given ISA temperature deviation;
(27) describe why and how the wind changes direction and speed with H in the friction layer in the northern and southern hemisphere (rule of thumb);
(28) describe and explain the origin and formation of mountain waves;
(29) explain how mountain waves may be identified through their associated meteorological phenomena;
(30) describe turbulence and gustiness;
(31) list common types of turbulence (convective, mechanical, orographic, frontal, and clearair turbulence);
(32) indicate the sources of atmospheric humidity;
(33) define ‘dew point’;
(34) define ‘relative humidity’;
(35) describe the relationship between temperature and dew point;
(36) estimate the relative humidity of the air based on the difference between dew point and temperature;
(37) explain the influence of relative humidity on the H of the cloud base;
(38) list cloud types typical for stable and unstable air conditions;
(39) identify by shape cirriform, cumuliform, and stratiform clouds;
(40) explain the influence of inversions on vertical movements in the atmosphere;
(41) name the factors contributing in general to the formation of fog and mist;
(42) name the factors contributing to the formation of haze;
(43) describe significant characteristics of orographic fog;
(44) summarise the conditions for the dissipation of orographic fog;
(45) list and describe the types of precipitation given in the aerodrome forecast (TAF) and aerodrome routine meteorological report (METAR) codes (drizzle, rain, snow, snow grains, ice pellets, hail, small hail, snow pellets, ice crystals, freezing drizzle, and freezing rain);
(46) assign typical precipitation types and intensities to different clouds;
(47) describe the boundaries between air masses (fronts);
(48) define ‘front’ and ‘frontal surface’ (‘frontal zone’);
(49) define ‘warm front’;
(50) describe the cloud, weather, ground visibility, and aviation hazards at a warm front depending on the stability of the warm air;
(51) explain the seasonal differences in the weather at warm fronts;
(52) describe the structure, slope, and dimensions of a warm front;
(53) define ‘cold front’;
(54) explain the seasonal differences in the weather at cold fronts;
(55) describe the structure, slope, and dimensions of a cold front;
(56) describe the cloud, weather, ground visibility, and aviation hazards in a warm sector;
(57) describe the cloud, weather, ground visibility, and aviation hazards behind the cold front;
(58) define the term ‘occlusion’;
(59) identify the typical flat pressure pattern on a surface weather chart;
(60) describe the weather associated with a flat pressure pattern;
(61) explain the general weather conditions under which ice accretion on airframe occurs;
(62) indicate in which circumstances ice may form on an aircraft on the ground: air temperature, humidity, precipitation;
(63) explain in which circumstances ice may form on an aircraft in flight: inside clouds, in precipitation, outside clouds, and in the absence of precipitation;
(64) describe the different factors influencing the intensity of icing: air temperature, amount of supercooled water in a cloud or in precipitation, amount of ice crystals in the air, speed of the aircraft, shape (thickness) of the airframe parts (wings, antennas, etc.);
(65) define ‘clear ice’;
(66) define ‘rime ice’;
(67) define ‘hoar frost’;
(68) state the ICAO qualifying terms for the intensity of icing;
(69) describe in general the hazards of icing;
(70) assess the dangers of the different types of ice accretion;
(71) state the ICAO qualifying terms for the intensity of turbulence;
(72) describe the effects of turbulence on an aircraft in flight;
(73) indicate the possibilities of avoiding turbulence
- (i) in the flight planning: weather briefing, choice of track, and altitude, and
- (ii) during flight: choice of appropriate track and altitude;
(74) define ‘wind shear’ (vertical and horizontal);
(75) describe the conditions in which wind shear forms and how it forms (e.g. thunderstorms, squall lines, fronts, inversions, land and sea breeze, friction layer, and relief);
(76) describe the effects of wind shear on flight;
(77) indicate the possibilities of avoiding wind shear in flight:
- (i) in the flight planning, and
- (ii) during flight;
(78) name the cloud types which indicate the development of thunderstorms;
(79) describe the different types of thunderstorms, their location, the conditions for and the process of their development, and list their properties (air mass thunderstorms, frontal thunderstorms, squall lines, supercell storms, orographic thunderstorms);
(80) assess the average duration of thunderstorms and their different stages;
(81) summarise the flight hazards of a fully developed thunderstorm;
(82) describe and assess ‘St. Elmo’s fire’;
(83) describe the effect of lightning strike on aircraft and flight execution;
(84) describe practical examples of flight techniques used to avoid the hazards of thunderstorms;
(85) describe the influence of a mountainous terrain on cloud and precipitation;
(86) describe the effects of the foehn;
(87) describe the influence of a mountainous area on a frontal passage;
(88) indicate the turbulent zones (mountain waves, rotors) on a sketch of a mountain chain;
(89) describe the reduction of visibility caused by precipitation (drizzle, rain, and snow);
(90) describe the differences between ground visibility, flight visibility, slant visibility, and vertical visibility when an aircraft is above or within a layer of haze or fog;
(91) define ‘ground visibility’;
(92) list the units used for visibility (m, km);
(93) define ‘RVR’;
(94) list the units used for RVR (m);
(95) compare visibility and RVR;
(96) define ‘ceiling’;
(97) name the unit and the reference level used for information about the cloud base (ft);
(98) define ‘vertical visibility’;
(99) name the unit used for vertical visibility (ft);
(100) interpret ground-weather radar images;
(101) describe the basic principle of airborne weather radars as well as the type of information they provide;
(102) describe the limits and errors of airborne weather radar information;
(103) interpret typical airborne weather radar images;
(104) decode and interpret significant weather charts (low-, medium-, and high-level charts);
(105) describe the flight conditions at designated locations or along a defined flight route at a given FL, based on a significant weather chart;
(106) describe, decode (by using a code table), and interpret the following aviation weather messages (given in written or graphical format):
- (i) METAR;
- (ii) aerodrome special meteorological reports (SPECI);
- (iii) trend forecast (TREND);
- (iv) TAF;
- (v) information concerning en route weather phenomena which may affect the safety of aircraft operations (SIGMET);
- (vi) information concerning en route weather phenomena which may affect the safety of low-level aircraft operations (AIRMET);
- (vii) area forecast for low-level flights (GAMET);
- (viii) automatic terminal information service (ATIS);
- (ix) meteorological information for aircraft in flight (VOLMET);
- (x) special air-report, and
- (xi) volcanic-ash advisory information;
(107) list in general the cases where a SIGMET and an AIRMET are issued; and
(108) describe, decode (by using a code table), and interpret the following messages: runway state message (as written in a METAR) and general aviation forecast (GAFOR).