Re: 747-400 Initial Cruise

Date:         03 Oct 97 01:18:33 
From:         domk1031@sp.zrz.tu-berlin.de (Burkhard Domke)
Organization: Technical University of Berlin, Germany
References:   1 2
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On 01 Oct 97 14:08:46 , "Michael F. Lechnar"
<michael.f.lechnar@boeing.com> wrote:

>At least in the case of the KUL-LHR flight, 26,000 ft was probably
>assigned by ATC.  Indian ATC is particulary notorious for keeping
>airplanes at low altitudes in their airspace.  The first flights out
>generally get the highest altitudes.
>
>The flight out of LHR was again probably limited by ATC rather than
>airplane performance.  BA's 747-400s are capable of at least 31,000 ft
>initial altitude capability at maximum certified takeoff weights

Does this apply also to, say, ISA+10 conditions?

An early LHA A340-200 AOM quoted an ICA of merely FL270 at MTOW under
those circumstances.

FWIW, four-engined airliners usually feature both a higher thrust and
wing loading than twins, provided their design is balanced regarding,
amongst others, the take-off (one engine inoperative), climb and
cruise thrust requirements. Hence quads (have to) cruise at lower
altitudes than twins by nature.

IIRC, Airbus set up a FL350 ICA requirement for the A3XX though...

Burkhard