THINGS THAT YOU SHOULD KNOW ABOUT ATMOSPHERE !

rudz · Post time 26-1-2007 09:51 AM

Mountain wave safety practices

Altitude 50 percent above the terrain - Turbulence caused by extreme mountain waves can extend into all altitudes that you might use, but dangerous turbulence can usually be avoided by clearing the mountains at least half again as high as the height of the mountain. In Colorado there are 54 peaks over 14,000-foot elevation. Does this mean we have to fly at 14,000 plus one-half (7,000) or 21,000 feet? No, use the base of the terrain to begin measuring. For example, if the surrounding terrain is 10,000 feet and the mountaintop is 14,000 feet, use one-half of the 4,000-foot value and fly 2,000 feet above the mountaintops.

Approach at a 45-degree angle - The rule-of-thumb of flying half again as high as the mountain is designed to reduce the risk of entering the turbulent rotor zone, but it does not necessarily give you a sufficient margin to allow for height loss due to downdrafts. You must have an escape route.

Avoid ragged or irregular-shaped lenticulars - Ragged and irregular-shaped lenticulars can contain the same turbulence as the rotor area.

Climb in lift - Dive in sink - By diving in sink, rather than trying to maintain altitude, the airplane is exposed to the effects of the downdraft for a lesser amount of time. Even though the rate of descent will likely be double or more the rate of climbing at the best rate-of-climb airspeed, the airplane will loose less altitude overall.

Avoid the rotor - If rotor clouds are not present, visualize the area of the rotor and avoid it.

Visualize the wave length - When flying parallel to the wave, fly in the updraft area.

rudz · Post time 26-1-2007 09:59 AM

line squalls

A long line of squalls and thunderstorms which sometimes accompanies the passage of a cold front is called a line squall (or squall line). It is usually associated with a fast moving cold front that is undercutting an unstable warm air mass. It may form anywhere from 50 to 300 nautical miles in advance of the front itself. The line squall is a long line of low black, roller like cloud, which often stretches in a straight line for several hundred miles, and from which heavy rain or hail falls for a short time. Thunder and lightning frequently occur. The squall is also accompanied by a sudden wind change from southerly or south-westerly to north or north-westerly, together with a sudden drop in temperature and a rise in barometric pressure. The actual wind squall lasts only for a few minutes but is often extremely violent, constituting a serious menace both to shipping and to airplanes. The signs indicating the approach of a line squall are unmistakable. Airplanes on the ground should be immediately hangared. Those in the air should at all costs avoid this violent weather phenomenon

p/s.. fenomena biasa yang berlaku di malaysia (kebiasaannya sewaktu southwest monsoon dan awal pagi)... burstnya boleh mencecah 40 - 50 knots (80km/j - 100km/j).. amat merbahaya terutamanya kepada fighter jet dan operasi chopper

seladanganas · Post time 19-2-2007 11:15 AM

ygaku heran ada sejenis angsa di ireland yg boleh terbang 30,000 kaki semasa migrasi. rekod burung paling tinggi terbang 37,500 kaki burung vulture yg berlanggar dgn k'tebang beberapa tahun dahulu. yg tak direkodkan mungkin siapa tahu. manusia lepas 10000 kaki shj dah susah nak bernafas.

rudz · Post time 22-2-2007 06:35 PM

Originally posted by seladanganas at 19-2-2007 11:15 AM
ygaku heran ada sejenis angsa di ireland yg boleh terbang 30,000 kaki semasa migrasi. rekod burung paling tinggi terbang 37,500 kaki burung vulture yg berlanggar dgn k'tebang beberapa tahun dahul ...

ada satu teori/hyphoteses??? (teman pun dah tak brapa nak ingat)...
ianya lebih kurang begini.... sekiranya u dicampakkan ke kaw. yang bertekanan kurang dari 50hPa relatif kepada tempat u sebelumnya dan ianya kurang dari 1 saat... maka u boleh meletup... (hyphoteses nie terpakai bagi kes2 tornadoes)..

begitu jugak waktu climb... pilot tak mencangak naik ( > 45 degree)... reasonnya ...perubahan tekanan yang secara tiba-tiba mampu membuatkan kita unconscious

guynextdoor · Post time 25-2-2007 10:38 PM

rudz · Post time 2-3-2007 10:17 PM

Originally posted by guynextdoor at 25-2-2007 10:38 PM

pada ketinggian 25000 kaki, seseorang tu boleh bertahan dalam 10 minit (org yg sihat dan di kawasan tropika)... tapi tahukah anda bahawa pasukan payung terjun kita menggunakan bekalan oksigen sewaktu terjun pada ketinggian tersebut..