B777 Max vs Optimum Altitudes
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Join Date: Jul 2001
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B777 Max vs Optimum Altitudes
Hello All
I was having a look at the Long Range Cruise Operating Table for the -200. On the left it gives you an optimum altitude and then the columns on the right give maximum altitudes relating to bank angle(buffet). Now in the burble in the text before all the graphs/tables begin it says that the optimum altitude given in the table equates to a 1.5G(48 degrees bank) buffet margin or more.
Then surely the optimum altitude column on the left should be the same as 1.5G column on the right? Infact they differ by a few hundred feet.
The -300 table follows the same principle...
Any ideas?
I was having a look at the Long Range Cruise Operating Table for the -200. On the left it gives you an optimum altitude and then the columns on the right give maximum altitudes relating to bank angle(buffet). Now in the burble in the text before all the graphs/tables begin it says that the optimum altitude given in the table equates to a 1.5G(48 degrees bank) buffet margin or more.
Then surely the optimum altitude column on the left should be the same as 1.5G column on the right? Infact they differ by a few hundred feet.
The -300 table follows the same principle...
Any ideas?
Join Date: Jul 2007
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I believe the maximum altitudes on the B777 are not limited by manoevre margins but cruise thrust availability. I do not have the QRH with me, will double check later. Cheers!
Join Date: Oct 1999
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If it's like B737NG optimum is based upon engine/airframe performance. Max alt is determined by either:
- structural
- buffet limit (different for JAA and FAA)
- thrust limit (esp at higher ISA deviations - sometimes opt alt is higher than max alt!)
- structural
- buffet limit (different for JAA and FAA)
- thrust limit (esp at higher ISA deviations - sometimes opt alt is higher than max alt!)
