Re: Singapore Airlines The A340 vs 777 saga continues

Date:         27 Aug 99 03:08:21 
From:         Pete Mellor <pm@csr.city.ac.uk>
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A few comments on airbus cruise altitudes (I forget exactly who made the
original comments):-

> >>Airbus Aircraft are traditionally not 'high flyers'. This is also
> >>causing SQ a certain amount of pain. Flights to Europe generally
> >>depart in the late afternoon and early evening, and are at or very
> >>near MGTOW.  The trip goes out of over the Bay of Bengal, which often
> >>has nasty weather (thunderstorms) in the early evening. Very bluntly,
> >>at high weights, the 777 and the 747's can fly a lot higher, giving
> >>the crew more choices about how to avoid weather (and provide a better
> >>ride for the passengers).
> >
> >Prove this one, please!  AI aircraft have a similar climb rate to the
> >777, and the 747 climb performance can be dismal...  Also, no-one can
> >convince me that any aircraft in commercial use can climb over a cu-nim
> >cloud - they can peak at over 60,000ft.....
>
> The issue isn't rate of climb, it is ceiling for a given  weight. Most
> Airbus aircraft  cannot make FL390 even empty!
...
> Have you ever been on a high weight Airbus aircraft and checked the
> cruise altitude?  Most Airbus aircraft use a supercritical wing that was
> optimized for lower altitudes than the Boeing wing. The good news is an
> Airbus aircraft generally suffers a lower fuel burn penalty for a less
> desireable altitude. The bad news is if the weather isn't  good, an
> Airbus is a lot more likely to have to go around rather than over the
> weather.

In 1995(?) I was in a Singapore Airlines A330 en route from Singapore
to Hong Kong. We spent much of the time well over 40,000 feet. (I think
we reached 45,000 at some point.) I know what the altitude was, since I
was in the jump seat looking over the pilot's shoulder (and, yes, I do
know enough about the instrument layout in the A320/330/340 cockpit to
know that I was looking at the right display! :-)

I made some notes. I don't have them to hand right now, but I'll check.

Pete Mellor, CSR, City University.
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