Results
#1. The vertical extent of the friction layer depends primarily on
The friction layer is a layer of air on the earth’s surface 2000 to 3000 ft (1 km) thick where the horizontal flow of air is disturbed by both thermal and mechanical turbulence.
caused by physical obstructions to the normal flow of air such as hills, mountains, coasts, trees and buildings.
#2. Low level wind shear is likely to be greatest
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt. As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#3. Which cloud type may indicate the presence of severe turbulence?
Altocumulus lenticularis, also known as lenticular cloud, is found downwind of mountainous or hilly areas, and is indicative of the presence of mountain wave activity. Because of its position downwind of high ground, moderate or even severe turbulence may be found beneath altocumulus lenticularis. However, the air in the lenticular clouds, themselves, is always smooth.
#4. Low level vertical wind shear can be expected during the night
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt. As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#5. What is the effect of a strong low level inversion?
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt. As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#6. 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
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt. As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#7. Vertical wind shear is
Vertical windshear is change in horizontal wind velocity with height. It is typically measured in knots per 100ft.
Horizontal windshear is change in wind velocity with horizontal distance and is common with the passage of fronts
#9. How does moderate turbulence affect an aircraft?
#10. In which zone of a jet stream is the strongest CAT to be expected?
Clear air turbulence (CAT). occurs around the boundaries of jet streams because of the large horizontal and vertical windshears. It is strongest near to, or just below, the jet axis on the cold air (low pressure) side with a secondary area above the axis
#11. On a clear summer day, turbulence caused by solar heating is most pronounced
During early afternoon low pressure areas form over land masses due to solar heating,
#12. What units are used to report vertical wind shear?
Vertical windshear is change in wind velocity with height
wind velocity is represented in Kt.
height in feet
#13. 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.”
#14. At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is
Altocumulus lenticularis, also known as lenticular cloud, is found downwind of mountainous or hilly areas, and is indicative of the presence of mountain wave activity. Because of its position downwind of high ground, moderate or even severe turbulence may be found beneath altocumulus lenticularis. However, the air in the lenticular clouds, themselves, is always smooth.
#15. 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?
Decreasing the speed will give more allowance for the thrust and we can climb faster
#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
#19. 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?
Seasonal and Diurnal Variation
The atmosphere becomes stable at lower levels after sunset due to radiational cooling. At the same time the winds also weaken in the lower layers. This results in the formation of waves, on the lee side of small and medium height mountains, called evening waves. These waves continue throughout, till the warming up after sunrise destroys the stability structure. In the case of large mountains, however, this effect is negligible.
In winters the winds are steady and strengthen with height and the atmosphere has suitable stability. Hence the mountain waves are more frequent in the winters.
in summers in the morning mountain waves are not frequent, hence Vfr should be conducted
#20. The most dangerous low level wind shears are encountered
Vertical windshear is change in wind velocity with height. It is typically measured in knots per 100ft. This type of windshear is very common during an inversion, therefore expect them at night and in well developed high pressure systems such as those found under the sub tropical high pressure belt
Thunderstorms
If the downdraught descends from beneath a cumulonimbus or cumulus congestus, it may come into contact with the ground, and then spread out, from the cloud itself, sometimes up to distances from the cloud of 15 – 20 miles. This type of phenomenon causes large changes in the direction and speed of the wind in the vicinity of the cloud, both vertically and horizontally, and may, thus, give rise to dangerous low level wind shear.
#21. 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?
#22. The degree of clear air turbulence experienced by an aircraft is proportional to the
Clear air turbulence (CAT). occurs around the boundaries of jet streams because of the large horizontal and vertical windshears.
#23. Which cloud type may indicate the presence of severe turbulence?
Altocumulus lenticularis, also known as lenticular cloud, is found downwind of mountainous or hilly areas, and is indicative of the presence of mountain wave activity. Because of its position downwind of high ground, moderate or even severe turbulence may be found beneath altocumulus lenticularis. However, the air in the lenticular clouds, themselves, is always smooth.
#24. Fallstreaks or virga are?
virga are trails of precipitation that fall from the underside of a cloud but evaporate or sublime before it can reach the earth’s surface
#25. The presence of altocumulus lenticularis is an indication of the
Altocumulus lenticularis, also known as lenticular cloud, is found downwind of mountainous or hilly areas, and is indicative of the presence of mountain wave activity. Because of its position downwind of high ground, moderate or even severe turbulence may be found beneath altocumulus lenticularis. However, the air in the lenticular clouds, themselves, is always smooth.
#26. Above and below a low level inversion the wind is likely to
As an aeroplane fly’s through an inversion, not only will the change of temperature cause the engine performance to change, but the abrupt change in wind speed and direction may significantly alter the flight path.
#27. At the top of orographic waves, in mountainous regions, the cloud most likely to be encountered is
Altocumulus lenticularis, also known as lenticular cloud, is found downwind of mountainous or hilly areas, and is indicative of the presence of mountain wave activity. Because of its position downwind of high ground, moderate or even severe turbulence may be found beneath altocumulus lenticularis. However, the air in the lenticular clouds, themselves, is always smooth.
#28. 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?
Inversion layer is reported just after take of, winds will change abruptly after take off, resulting in lower climb and possible windhear, we should take opposite of the wind being reported as after take off immediate change of wind direction are expected