Green dot
Good morning,
A321 Neo… somebody knows why green dot is behaved like that at FL 390? And why there is a limit at 292kt? |
Originally Posted by michelda
(Post 11580266)
Good morning,
A321 Neo… somebody knows why green dot is behaved like that at FL 390? And why there is a limit at 292kt? |
Are you referring to the situation where Green Dot ends up below VLS? I thought that bug was fixed over 5 years ago?
|
https://cimg6.ibsrv.net/gimg/pprune....ba0408743.jpeg
At FL390 green dot is not following “standard” law of increasing with altitude. At GW of 100t, above FL300 green dot unchange |
Originally Posted by michelda
(Post 11580586)
https://cimg6.ibsrv.net/gimg/pprune....ba0408743.jpeg
At FL390 green dot is not following “standard” law of increasing with altitude. At GW of 100t, above FL300 green dot unchange Airbus Aerodynamics can be a fickle subject.. :-) |
Originally Posted by michelda
(Post 11580586)
https://cimg6.ibsrv.net/gimg/pprune....ba0408743.jpeg
At FL390 green dot is not following “standard” law of increasing with altitude. At GW of 100t, above FL300 green dot unchange |
How are you getting a 100t A321 to FL390?
I get a Rec Max of FL331 at 93.5t. |
I vaguely recall this being addressed in one of the issues of the Safety First magazine.
|
Originally Posted by waterbottle
(Post 11580734)
How are you getting a 100t A321 to FL390?
I get a Rec Max of FL331 at 93.5t. |
https://cimg0.ibsrv.net/gimg/pprune....38ed3b9ba1.png
Taken on a NEO at FL390…. Fairly positive 292 knots would be destructive at that altitude! |
Originally Posted by hikoushi
(Post 11583738)
https://cimg0.ibsrv.net/gimg/pprune....38ed3b9ba1.png
Taken on a NEO at FL390…. Fairly positive 292 knots would be destructive at that altitude! |
Originally Posted by 321XLR
(Post 11584105)
that is a pretty narrow window between VLS and barber pole. What was your "OPT altitude" per the box?
Then again what do I know. (Checks door) |
That looks fairly normal for a heavy A321 up high.
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Originally Posted by 321XLR
(Post 11584105)
that is a pretty narrow window between VLS and barber pole. What was your "OPT altitude" per the box?
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Originally Posted by B2N2
(Post 11584128)
From a Boeing guy that looks alright to me.
Then again what do I know. (Checks door) |
That margin will be ok even in moderate turbulence. Checked more than once.
|
Green dot is always on VLS at MAX ALT in our 321 NEOs, whereas on the CEO there's usually a very small gap.
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Thanks all for your replies!!
Just few more question. I think Airbus knows that at FL 390 is not possible to fly at 292 kt…..so why they inserted values instead of dashes or blank box? I agree that at high altitude the green dot value is equal to vls, but how can be lower than at low altitude? |
Originally Posted by Gero
(Post 11590743)
That margin will be ok even in moderate turbulence. Checked more than once.
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Originally Posted by michelda
(Post 11592643)
I think Airbus knows that at FL 390 is not possible to fly at 292 kt…?
When they did the flight diving test on the 777-300 the T33 chase plane clocked them at 1.01M. Not sure of the altitude at which it happened. |
I think you would need an exceptional T-33 to get to M1.01?
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Originally Posted by hikoushi
(Post 11593450)
….how many times have you personally actually experienced legitimate moderate turbulence while flying with those performance margins? 🍻
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Originally Posted by kenparry
(Post 11593588)
I think you would need an exceptional T-33 to get to M1.01?
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