Mixed practice

Meteorology · Chapter 30 · DGCA CPL and ATPL

Three mixed tests, one question from every chapter. Each answer tells you which chapter to revise.

Remember

Mixed practice: test 1

Test 1

One question from every chapter, in a mixed order. Each answer names the chapter to revise.

  1. A pilot sees a large ring, always the same size, round the sun through a thin milky veil. The cloud is made of

    • dust
    • water droplets
    • ice crystals

    Answer: ice crystals. A 22° halo comes from refraction in hexagonal ice crystals, typically in cirrostratus. (Revise chapter 10: Optical Phenomena.)

  2. Heavy showers fall from a towering cloud while a few kilometres away the sky is clear. The cloud is

    • cumulonimbus
    • altostratus
    • nimbostratus

    Answer: cumulonimbus. Showers come from convective cloud and fall in shafts; steady rain over wide areas comes from layer cloud. (Revise chapter 11: Precipitation.)

  3. In a METAR, 27015G28KT means

    • wind from 270° at 15 kt, gusting 28 kt
    • wind towards 270°
    • visibility 2700 m

    Answer: wind from 270° at 15 kt, gusting 28 kt. Direction is where the wind comes from; G gives the gusts. (Revise chapter 25: METAR, SPECI and TREND.)

  4. Which three things does a thunderstorm need?

    • Strong wind, cloud and cold air
    • Fog, an inversion and dry air
    • Instability, moisture and a lifting trigger

    Answer: Instability, moisture and a lifting trigger. Without all three the cloud cannot grow tall. (Revise chapter 13: Thunderstorms.)

  5. A cloudless thermal leaves the hot runway at Jodhpur at 40 °C. Without condensing, what will its temperature be 2 km up?

    • About 27 °C
    • About 36 °C
    • About 20 °C

    Answer: About 20 °C. Unsaturated rising air cools at about 9.8 °C per km: 40 − 2 × 9.8 ≈ 20 °C. (Revise chapter 9: Stability.)

  6. Mountain waves need

    • a strong wind across the ridge and a stable layer near the crest
    • a warm front
    • calm air

    Answer: a strong wind across the ridge and a stable layer near the crest. The stable air bounces after crossing the ridge, setting up standing waves downwind. (Revise chapter 17: Mountain Waves.)

  7. North India's winter rain and Himalayan snow come mainly from

    • tropical cyclones
    • western disturbances
    • the south-west monsoon

    Answer: western disturbances. They pass from the west, a few times a month, between December and March. (Revise chapter 19: Climatology of India.)

  8. Which office provides forecasts and briefings for flights from its own airfield?

    • The Aerodrome Meteorological Office (AMO)
    • A radar station
    • The WMO in Geneva

    Answer: The Aerodrome Meteorological Office (AMO). An AMO serves its aerodrome; smaller Aeronautical Met Stations (AMS) mainly observe and report. (Revise chapter 21: Met Services.)

  9. A RAREP is

    • a pilot report
    • a satellite bulletin
    • a radar weather report

    Answer: a radar weather report. It gives the position, extent, intensity, movement and tops of radar echoes. (Revise chapter 27: RAREP, SIGMET and Satellite Bulletin.)

  10. A clear, calm winter night in Lucknow. When is the temperature usually lowest?

    • Just after sunrise
    • At sunset
    • Around midnight

    Answer: Just after sunrise. The ground keeps losing heat until the morning sun outweighs it, so the minimum comes shortly after dawn. (Revise chapter 3: Temperature.)

  11. A clear, calm, moist night after rain at Delhi. Which fog is most likely by dawn?

    • Advection fog
    • Radiation fog
    • Frontal fog

    Answer: Radiation fog. Clear skies let the ground cool, light wind keeps the chilled air in place, and moisture is plentiful. (Revise chapter 7: Visibility and Fog.)

  12. At Delhi the wind is from the east. Using Buys Ballot's rule, where is the lower pressure?

    • To the north
    • To the east
    • To the south

    Answer: To the south. Back to an easterly wind you face west; low pressure is on your left, to the south. (Revise chapter 6: Winds.)

  13. Clear air turbulence is turbulence

    • at high level with no visible cloud
    • inside CB
    • only near the ground

    Answer: at high level with no visible cloud. It comes from strong wind shear, often near jets, and gives no visual warning. (Revise chapter 16: Clear Air Turbulence.)

  14. Air that has spent a week over the warm Arabian Sea before reaching Mumbai would be classed as

    • maritime tropical
    • maritime polar
    • continental polar

    Answer: maritime tropical. A sea source makes it maritime; a warm, low-latitude source makes it tropical. (Revise chapter 14: Air Masses, Fronts and WDs.)

  15. On a T-4, heights are usually given as

    • metres above the airfield
    • pressure in hPa only
    • flight levels

    Answer: flight levels. Cross-sections show the route against flight levels. (Revise chapter 29: T-3 and T-4.)

  16. Tropical cyclones need sea surface temperatures of at least about

    • 15 °C
    • 35 °C
    • 26-27 °C

    Answer: 26-27 °C. Warm water supplies the moisture and latent heat that power the storm. (Revise chapter 18: Tropical Systems and Cyclones.)

  17. Flat-based cumulus at the same height on a summer morning over the plains. The bases mark

    • the tropopause
    • the freezing level
    • the condensation level of the rising thermals

    Answer: the condensation level of the rising thermals. Each thermal cools as it rises and condenses at the same level, giving a common flat base. (Revise chapter 8: Vertical Motion and Clouds.)

  18. Which afternoon gives the longest take-off run for the same aircraft and weight?

    • Leh, 5 °C
    • Leh, 35 °C
    • Mumbai, 35 °C

    Answer: Leh, 35 °C. High and hot together give the highest density altitude: least air for wings, engines and propellers. (Revise chapter 4: Air Density.)

  19. At 0500 the temperature is 24 °C and the dew point 23 °C at Kolkata. What is most likely soon?

    • Mist or fog
    • Clear, dry air
    • A dust storm

    Answer: Mist or fog. With only 1 °C between temperature and dew point, a little more cooling saturates the air. (Revise chapter 5: Humidity.)

  20. On a station model, the circle in the middle shows

    • the pressure
    • the total cloud amount
    • the wind speed

    Answer: the total cloud amount. The fraction filled in gives the cloud cover in oktas. (Revise chapter 24: Station Models.)

  21. A jet stream is a narrow band of strong wind, by convention at least

    • 60 kt
    • 200 kt
    • 20 kt

    Answer: 60 kt. Jets are usually found near the tropopause, often 100-150 kt in the core. (Revise chapter 15: Jet Streams.)

  22. An airliner climbs out of Chennai into a cloudless sky and levels at FL370. In which layer is it cruising?

    • Stratosphere
    • Mesosphere
    • Troposphere

    Answer: Troposphere. Over the tropics the tropopause is near 16-17 km (FL520-560), so FL370 is still well inside the troposphere. (Revise chapter 1: The Atmosphere.)

  23. The tropics receive more radiation than they lose, so the atmosphere and oceans must

    • store heat forever
    • carry heat to the equator
    • carry heat towards the poles

    Answer: carry heat towards the poles. The general circulation moves the surplus poleward. (Revise chapter 20: General Circulation.)

  24. Station pressure is measured with

    • a precision aneroid or mercury barometer
    • a thermometer
    • an anemometer

    Answer: a precision aneroid or mercury barometer. The reading is then reduced to QFE, QNH and QFF. (Revise chapter 23: Met Instruments.)

  25. Before a flight, a crew should get

    • a met briefing or documents covering the route, destination and alternates
    • only the destination METAR
    • nothing if the sky is clear

    Answer: a met briefing or documents covering the route, destination and alternates. Good planning needs the whole picture. (Revise chapter 28: Documentation and Briefing.)

  26. A weather radar sees mainly

    • fog
    • clear air turbulence
    • precipitation

    Answer: precipitation. Radar echoes come from raindrops, hail and snow; small cloud droplets and clear air hardly show. (Revise chapter 22: Radar and Satellites.)

  27. Large supercooled drops striking the wing at −3 °C will most likely form

    • rime ice
    • hoar frost
    • clear (glaze) ice

    Answer: clear (glaze) ice. Big drops freeze slowly, spread back and form heavy, glassy ice that is hard to shed. (Revise chapter 12: Ice Accretion.)

  28. Leaving Ahmedabad (QNH 1016) for a field with QNH 1004, you forget to reset the altimeter. On arrival it shows

    • more than your true height
    • less than your true height
    • your true height

    Answer: more than your true height. Into lower pressure the reading is too high: you are lower than it says. (Revise chapter 2: Pressure and Altimetry.)

  29. A TAF is

    • an observation
    • a forecast for one aerodrome over a stated period
    • a route forecast

    Answer: a forecast for one aerodrome over a stated period. It uses the same codes as a METAR plus change groups. (Revise chapter 26: Aviation Weather Forecasts.)

Takeaway: 29 questions.

Mixed practice: test 2

Test 2

One question from every chapter, in a mixed order. Each answer names the chapter to revise.

This lesson is part of the Meteorology plan. See plans

Mixed practice: test 3

Test 3

One question from every chapter, in a mixed order. Each answer names the chapter to revise.

This lesson is part of the Meteorology plan. See plans