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A340SR
23rd Apr 2008, 15:52
One more question for today...
Thanks all in advance...

The book says REC MAX alt provides 0.3 buffet margin..
or something....

... Shame on me... but To me...this line sounds like from
outer space....

Can anyone kindly explain what this means.....?

Mad (Flt) Scientist
24th Apr 2008, 04:50
I'd guess that it means you can pull 1.3'g' (i.e. 0.3'g' above S&L flight) at the speed&altitude concerned and JUST hit buffet.

(That's what our books would mean by a corresponding statement, anyway)

john_tullamarine
24th Apr 2008, 04:53
gives you a small margin below buffet to allow for minor turbulence and manoeuvring (ie turns)

guiones
26th Apr 2008, 08:08
Recommended maximum altitude (REC MAX)
The recommended maximum altitude is the lowest of the maximum altitude that :

The aircraft can reach with a 0.3 g buffet margin


The aircraft can fly in level flight at MAX CRZ rating


The aircraft can maintain a V/S of 300 feet/minute at MAX CLB thrust


The aircraft can fly, at a speed higher than green dot, and lower than VMO/MMO
for which the aircraft is certified.



The REC MAX altitude is displayed on the PROG page.
Anti-ice is not taken into account for this computation. Refer to QRH graphs if icing conditions are expected.
A maximum altitude using a 0.2 g buffet margin is also computed. It is not displayed, but the system uses it to limit CRZ ALT entry.

Hope it helps!