Re: Singapore Airlines The A340 vs 777 saga continues

Date:         07 Aug 99 01:22:31 
From:         James Matthew Weber <jmweber@goodnet.com>
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>Frankly, 6.5 tons is not a huge amount - not at this stage of
>development, anyway. Believe me, more was shaved off the A340-200 before
>EIS...  and RR have never delivered an engine that doesn't do as
>advertised.  Especially in reliability terms - go ask BA what they think
>of the GE90 on 777 - they love it so much that they are dumping it in
>favour of Trent on the new order.

Vary interesting comments, except that they are inaccurate. Ask almost
any RB211-524G/H operator.  Every 524G/H-T contract contains a final
settlement for the fuel economy short fall on the original engine. RR
has been paying penalties to almost every operator (QF, BA, CX....) from
day zero.

The 524G/H NEVER made fuel economy guarantees.  BA made lot noise about
the GE90, I am convinced it was a PR Campaign.  When you check
mechanical dispatch reliabliity and compare the RR, PW and GE powered
777 fleets, guess which one was has the  best mechanical dispatch
reliability? The GE powered fleet. Obviouslly if the GE90 was so
terrible it would have impacted Mechanical Dispatch reliability,
wouldn't it?  Obviosly the reliability on the GE engine cannot be
materially worse than the PW or RR engine.

>The 747 is a quick aircraft, but I doubt this is true for the 777, which
>has a stated cruise of 30kts less than A340.

What reference did you get that out of? In long haul flight, the 777
cruises at M.84-.84

An A340-500/600 maybe. Certainly not for an A340-200/300, which is the
only A340 in service today. Some documents show the A340-200/300 may in
long range economy cruise be 70kts slower than either 777 and 747. The
777's cruise speed was a major selling point against the A340-200/300

>>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!  Boeing learned the
importance of this early one with the 747, and each version of the 747
has had improved high weight altitude capability. At MGTOW a 747-100 can
reach only 25,000 feet. A 777-200 can go directly to FL390 at MGTOW.
This can be extremely useful in both getting over weather, and getting
over traffic.

Clouds tops may indeed reach 60,000 feet, but there aren't may up there.
Over the Bay of Bengal, there is a lot more cloud in front of you at
FL250 than there is at FL370, so there is less to 'dodge'

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.

James Matthew Weber   (623) 587 7514 .  Fax  (480) 638 1316