There are two other type of fronts; the occluded, and the station ary. The occluded front is a combination of both cold and warm front conditions. It occurs when a cold front overtakes a warm front and traps warm air between them. Weather condi tions are similar to the cold front. The stationary front is a front which does not move.
Condensation The process by which water vapor becomes visible moisture, in the form of clouds and fog, is called condensation. Condensation is the formation of water droplets on small bits of matter such as dust particles, smoke, or salt spray when the content of water vapor is high enough and cooled to the point of saturation. The most common example of condensation is the cloud.
Clouds are classified by their general appearance. The “cumuliform” cloud is billowy and dome shaped and can appear to rise forever. The “stratiform” cloud, on the other hand, is comprised of hori zontal layers which vary in thickness with little vertical build up.
Stratus: Generally grey, layered low cloud limited to about 6000’.
Cumulus: Detached and dense with sharp outlines, this form of cloud develops vertically in rising domes or towers, the upper parts resembling a cauliflower. Their upper limit is usually 23,000’.
Cirrus: Also detached but delicate or fibrous in appearance, cirrus cloud is sometimes associated with light turbulence at high level. Its upper limit is around 45,000’.
Fog Being unable to land at the intended destination can cause great inconvenience to the passengers. Fog is caused by moist air being sufficiently cooled so that the resultant suspended water droplets reduce visibility below levels that are needed to take-off or land.
Precipitation Water from the earth’s surface constantly evaporates into the atmosphere as water vapor. When the air can no longer hold the water vapor (warm air can hold more water vapor than cold air), the air be comes saturated and visible moisture is formed and precipitation, in the form of rain or snow, occurs.
Thunderstorms
One of the most hazardous weather phenomena is the thunderstorm. De pending on air conditions, thunderstorms may form in scattered conditions or in lines extending hundreds of miles. Very seldom will the flight crew elect to pen etrate a line of thunderstorms. The aircraft radar is used to keep a safe distance and circum-navigate the nucleus of these storm cells.
The thunderstorm forms as a result of rapid rising and cooling air. Rapidly rising air creates up drafts, down drafts, severe turbulence, icing, hail, and heavy rains. Sky condi tions can look eerie. At night, lightning will appear as if it is right next to the airplane even though it’s miles away. Turbulence from these thunderstorms
are a big concern for passenger safety. Everyone should be seated with seat belts fastened when in the vicinity of thunderstorms.
Turbulence Turbulence is the single greatest cause of in-flight injuries. Turbulence can be caused by a number of factors: Thermal activity caused by the warming and cooling of air as it passes over warm or cool ter rain; wave activity caused by air masses passing over mountainous terrain; or the winding and bend ing upper level winds called “jet
Aviation Basics 10
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
