Jetstreams
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Jetstreams
I was asking an instructor a question on jetstreams. If a pilot were to try to fly in an area where jetstream exists to shorten the trip time and burn less fuel, would the pilot want to climb up to the area of jetstream or descent to a level where jetstream exists?
On the topic of meteorlogy, does anyone know the abbreviations for QNH and QNE or QFF?
On the topic of meteorlogy, does anyone know the abbreviations for QNH and QNE or QFF?
Not sure what the first question is but for the second one l did a ten second Google and found this http://www.fact-index.com/t/tl/tlas_...aa_to_tzz.html
halas
halas
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SB - I think the question is a little confused? I'll try to answer what I think you ask.
If you are flying above the level of the jetstream, it MAY be advantageous to descend to take advantage of a higher tailwind.
It depends on relative wind speeds and the change in cruise level. Performance charts for your 'one fast jet' (which from your profile you will have access to?) will tell you. If you are flying BELOW the jet, generally a climb will be beneficial for an improved tailwind.
All this depends on:
Turbulence/weather at jetstream level, and
How far above/below 'optimum' cruise level you will cruise.
QNH etc do NOT have abbreviations - they ARE in a sense 'abbreviations'. They came into being during the days of Morse code to avoid sending too many letters.
If you are flying above the level of the jetstream, it MAY be advantageous to descend to take advantage of a higher tailwind.
It depends on relative wind speeds and the change in cruise level. Performance charts for your 'one fast jet' (which from your profile you will have access to?) will tell you. If you are flying BELOW the jet, generally a climb will be beneficial for an improved tailwind.
All this depends on:
Turbulence/weather at jetstream level, and
How far above/below 'optimum' cruise level you will cruise.
QNH etc do NOT have abbreviations - they ARE in a sense 'abbreviations'. They came into being during the days of Morse code to avoid sending too many letters.
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In days gone by, pressure pattern navigation did just as you describe, alter course and (many times) altitude to achieve the maximum ground speed and hence least flying time, even if the distance traveled was greater.
Of course the reverse was true as well, adjust the flight path (and altitude) to achieve the least headwind.
In these cases, the flight path was randomly curved, so will not work in todays airspace, due to fixed tracks.
In the 'good 'ole days' the Navigator did all the work...leaving time for the guys up front to read the newspaper.
Of course the reverse was true as well, adjust the flight path (and altitude) to achieve the least headwind.
In these cases, the flight path was randomly curved, so will not work in todays airspace, due to fixed tracks.
In the 'good 'ole days' the Navigator did all the work...leaving time for the guys up front to read the newspaper.
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The two prevelent ones are the Sub Tropical and the Polar Front jetstreams. Nocturnal jetstreams are low level ones, at night, sometimes in the winter.
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As Panama Jack states there are principally two jetstream bands around the earth in each hemisphere caused by tropopause breaks. The Polar Front jetstreams are at about 60 degrees latitude, the Subtropical jetstreams at about 30 degrees latitude.
As the Coriolis force deflects the winds to the right in the Northern hemisphere and to the left in the Southern hemisphere, jetstreams always blow from West to East.
There are local jetstreams too, associated with fronts or low pressure areas.
To take advantage of the tailwind you should fly in the warm air as high as possible (you are out of the CAT area and the slope of the wind speeds is more shallow to the warm side).
To avoid headwind you should fly in the cold air as low as possible (you are out of the CAT area and wind speeds decrease very rapidly on the cold side).
Hope this helps!
As the Coriolis force deflects the winds to the right in the Northern hemisphere and to the left in the Southern hemisphere, jetstreams always blow from West to East.
There are local jetstreams too, associated with fronts or low pressure areas.
To take advantage of the tailwind you should fly in the warm air as high as possible (you are out of the CAT area and the slope of the wind speeds is more shallow to the warm side).
To avoid headwind you should fly in the cold air as low as possible (you are out of the CAT area and wind speeds decrease very rapidly on the cold side).
Hope this helps!
