Vayudoot Aviation

1. A wide body aircraft takes off on a clear night in Dhahran, Saudi Arabia. Shortly after take off the aircraft’s rate of climb drops to zero. This can be due to

sand/dust in the engines

very pronounced downdrafts

low relative humidity

a very strong temperature inversion

2. The turbulence which occurs at high flight levels (above FL 250) is mainly of the type Clear Air Turbulence. In what way can moderate to severe Clear Air Turbulence affect an aircraft, the flight and the passengers?

The turbulence is a small scale one and can cause damage of worn out type. The manoeuvring of the aircraft will be made more difficult or even impossible. For the passengers the flight will be unpleasant.

The turbulence can be resembled with the roughness of a washing-board (small scale) and will not have influence on the aircraft and its solidity, but will make flight a little more difficult. The passengers will seldom notice anything of this turbulence

The turbulence is a large scale one (waving) so that the aircraft will be difficult to manoeuvre. The passengers will feel some discomfort.

The turbulence is wave like which makes the flight unpleasant for the passengers but the manoeuvring will not be affected essentially

3. What units are used to report vertical wind shear?

kt

kt/100 FT.

m/sec.

m/100 FT.

4. You intend to carry out a VFR flight over the Alps, on a hot summer day, when the weather is unstable. What is the best time of day to conduct this flight?

Morning.

Mid-day.

Early evening.

Afternoon

5. Low level vertical wind shear can be expected during the night

and early morning only in winter

in association with radiation inversions

and early morning only in summer

in unstable atmospheres

6. In which zone of a jet stream is the strongest CAT to be expected?

The cold air side of the core

Exactly in the centre of the core.

The warm air side of the core.

7. Fallstreaks or virga are?

gusts associated with a well developed Bora

water or ice particles falling out of a cloud that evaporate before reaching the ground

strong downdraughts in the polar jet stream, associated with jet streaks

strong katabatic winds in mountainous areas and accompanied by heavy precipitation

8. On a clear summer day, turbulence caused by solar heating is most pronounced

immediately after sunset

during early morning hours before sunrise

about midmorning

during the early afternoon

9. Under which of the following conditions is the most severe CAT likely to be experienced?

A westerly jet stream at low latitudes in the summer

A jet stream, with great spacing between the isotherms

A straight jet stream near a low pressure area

A curved jet stream near a deep trough

10. Which of the following conditions are most favourable to the formation of mountain waves?

Either stable or unstable air at mountain top and a wind of at least 30 knots blowing parallel to the mountain ridge.

Stable air at mountain top altitude and a wind at least 20 knots blowing across the mountain ridge.

Moist unstable air at mountain top and wind of less than 5 knots blowing across the mountain ridge.

Unstable air at mountain top altitude and a wind at least 20 knots blowing across the mountain ridge.

11. Which cloud type may indicate the presence of severe turbulence?

Altocumulus lenticularis

Nimbostratus

Cirrocumulus

Stratocumulus

12. What is normally the most effective measure to reduce or avoid CAT effects?

Change of flight level.

Change of course.

Decrease of speed.

Increase of speed.

13. At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is

cumulus mediocris.

cirrus.

altocumulus lenticularis.

cirrostratus.

14. What is the effect of a strong low level inversion?

It promotes vertical windshear.

It results in good visual conditions

It prevents vertical windshear

It promotes extensive vertical movement of air.

15. The presence of altocumulus lenticularis is an indication of the

development of thermal lows

presence of mountain waves

presence of valley winds

risk of orographic thunderstorms

16. All pilots encountering Clear Air Turbulence are requested to report it. You experience CAT which causes passengers and crew to feel definite strain against their seat belt or shoulders straps. Unsecured objects are dislodged. Food service and walking are difficult. This intensity of CAT should be reported as

extreme

light

severe

moderate

17. Vertical wind shear is

horizontal variation in the vertical wind

vertical variation in the horizontal wind

horizontal variation in the horizontal wind

vertical variation in the vertical wind

18. The degree of clear air turbulence experienced by an aircraft is proportional to the

intensity of the solar radiation

stability of the air

height of the aircraft

intensity of vertical and horizontal windshear

19. A zone of strong convection currents is encountered during a flight. In spite of moderate gust you decide to continue the flight. What are your precautionary measures?

Increase the speed / try to climb above the zone of convective currents if aircraft performance parameters allow.

Decrease the speed / try to climb above the zone of convective currents if aircraft performance parameters allow

Increase the speed / try to descend below the zone of convective currents.

Decrease the speed / try to descend below the zone of convective currents

20. A flight is to depart from an airport with runways 09 and 27. Surface wind is 270/05; an inversion is reported at 300 feet with turbulence and wind shear. The wind just above the inversion is 090/30. What is the safest departure procedure?

Depart on runway 09 with a tailwind.

Depart runway 27 with as steep an ascent as possible.

Take-off is not possible under these conditions.

Depart runway 27 with maximum throttle during the passage through the inversion.

21. Low level wind shear is likely to be greatest

at the condensation level when there is strong surface friction

at the top of a marked surface-based inversion

at the top of the friction layer

at the condensation level when there is no night radiation.

22. Above and below a low level inversion the wind is likely to

change in speed but not in direction

change significantly in speed and direction

change in direction but not in speed

experience little or no change in speed and direction

23. Which cloud type may indicate the presence of severe turbulence?

Altocumulus lenticularis

Cirrocumulus

Stratocumulus

Nimbostratus

24. Which degree of aircraft turbulence is determined by the following ICAO description? “There may be moderate changes in aircraft attitude and/or altitude but the aircraft remains in positive control at all times. Usually, small variations in air speed. Changes in accelerometer readings of 0.5 to 1.0 g at the aircraft’s enter of gravity. Occupants feel strain against seat belts. Loose objects move about. Food service and walking is difficult.”

Moderate.

Light.

Severe

Violent.

25. At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is

cumulus mediocris

cirrostratus.

altocumulus lenticularis.

cirrus.

26. The vertical extent of the friction layer depends primarily on

stability, wind speed, roughness of surface

temperature, local time, environmental lapse rate

roughness of surface, temperature, local time

wind speed, roughness of surface, temperature

27. The most dangerous low level wind shears are encountered

near valleys and at the windward side of mountains.

during any period when wind speed is greater than 35 kt and near valleys

when strong ground inversions are present and near thunderstorms

in areas with layered clouds and wind speeds higher than 35 kt

28. How does moderate turbulence affect an aircraft?

Continued flight in this environment will result in structural damage.

Rapid and somewhat rhythmic bumpiness is experienced without appreciable changes in altitude or attitude

Changes in altitude or attitude occur but the aircraft remains in positive control at all times.

Large, abrupt changes in altitude or attitude occur but the aircraft may only be out of control momentarily

Question Bank

Questions for TURBULENCE 1