Operational Flight Plan
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Operational Flight Plan
Dear all please advise on the attached sample flight plan what is the item s showing values between waypoints with the numbers 7 4 2 1 1
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Join Date: Oct 2007
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It depends upon the model the OFP uses to calculate wind, but yes it can be used to identify potential areas of clear air turbulence when used with other meteorological products.
For example, at my operator that value indicates the amount of shear over a 1,000 ft. change in altitude (while another operator may use 2,000 ft.).
In your example and within the model used at my operator, it means the wind will change by 7 knots per 1,000 ft. - for the “7” value, of course - if I were to decide to climb or descend from the planned altitude at that waypoint. Shear values are typically not given for climbs and descents as the variation is too large.
Is that going to be bumpy? Who knows? I’ll look at all the other weather charts I’m given. Maybe it’s a nice, stable atmosphere and a value of 7 is nothing. On the other hand, maybe I’m flying over an active TROWL and I’m going to have my butt handed to me.
Maybe I have a value of 0 indicating no change in wind speed, but the wind is 90 degrees to a mountain range and I’m going to be sitting in the wrong spot of a mountain wave.
I’ve seen values as high as 13 on charts and it’s been super smooth, while a value of 0 resulted in all the sick bags being full (the aforementioned mountain wave).
The value itself means relatively nothing if you use it on its own. Yes, typically the higher the number the greater the chance you’ll encounter turbulence, and the higher the number the greater the severity of the turbulence - but it also requires all other things be equal, which means check your charts.
For example, at my operator that value indicates the amount of shear over a 1,000 ft. change in altitude (while another operator may use 2,000 ft.).
In your example and within the model used at my operator, it means the wind will change by 7 knots per 1,000 ft. - for the “7” value, of course - if I were to decide to climb or descend from the planned altitude at that waypoint. Shear values are typically not given for climbs and descents as the variation is too large.
Is that going to be bumpy? Who knows? I’ll look at all the other weather charts I’m given. Maybe it’s a nice, stable atmosphere and a value of 7 is nothing. On the other hand, maybe I’m flying over an active TROWL and I’m going to have my butt handed to me.
Maybe I have a value of 0 indicating no change in wind speed, but the wind is 90 degrees to a mountain range and I’m going to be sitting in the wrong spot of a mountain wave.
I’ve seen values as high as 13 on charts and it’s been super smooth, while a value of 0 resulted in all the sick bags being full (the aforementioned mountain wave).
The value itself means relatively nothing if you use it on its own. Yes, typically the higher the number the greater the chance you’ll encounter turbulence, and the higher the number the greater the severity of the turbulence - but it also requires all other things be equal, which means check your charts.
Last edited by +TSRA; 10th Jan 2018 at 10:38. Reason: Added statement for clarity.
Agree - almost certainly Jetplan / Jeppessen.
Its outlined in the Jetplan user manual with a nice formula. Suffice to say that it is over 2000', and the higher the number, the worse!
Its outlined in the Jetplan user manual with a nice formula. Suffice to say that it is over 2000', and the higher the number, the worse!
