Re: A330-300HGW

Date:         09 May 97 03:29:01 
From:         "Udayan V. Bhapkar" <ubhapkar@erols.com>
Organization: Erol's Internet Services
References:   1
View raw article
  or MIME structure

Roger Chung-Wee wrote:
>
> I hear that Airbus will be offering a higher gross weight version of
> the A330-300 to provide more competition for the 777-200IGW.  The
> A330-300HGW could be available by late 1998.  The MTOW will increase
> by 12 tonnes to 230 tonnes and the range will increase by as much as
> 1,300km to 10,200km.  But the fuel capacity will be unchanged because
> the A330-300HGW will not have the A330-200's central fuel tank.  So,
> how will the A330-300HGW fly the same payload further than the
> A330-300 or a bigger payload over a similar distance?  There must be
> something else, maybe more powerful and efficient engines or more
> aerodynamic wings.

The answer lies in the fact that at MTOW, in most cases, one cannot
choose maximum payload AND maximum fuel; such a combination will take
you over MTOW.  Instead, if one chooses to operate at max payload, then
the MTOW limitation will force you to use only a portion of the max fuel
capacity, and similarly, at max fuel, one cannot load up to max payload
(note tat the max payload is usually quite a bit more than the weight of
the passengers, and allows for a fair amount of revenue cargo.
If you want to look at numbers, consider the specs in the AWST Oct 4,
1993 test flight:

Operating weight empty:	119.9 tonnes
Max payload:		 44.1 tonnes
Max fuel capacity:	 77.9 tonnes
MTOW:			212   tonnes

The first three items add up to 241.9 tonnes, which is greater than
MTOW.  At MTOW and max payload, 48 tonnes of fuel can be carried.  At
max fuel, only 14.2 tonnes of payload can be carried.  Only if MTOW were
increased to 241.9 tonnes could one reach the max payload and fuel
capacity simultaneously.  The range that is quoted is usually not the
absolute maximum range, but the range with a specified payload, and with
fuel resereves.

For the 777-200IGW, the following numbers are observed:

Operating weight empty:	305,000 lbs
Max payload:		125,000 lbs
Max fuel capacity:	299,500 lbs
MTOW:			632,500 lbs

The first three items add up to 729,500 lbs.  Therefore, the MTOW would
need to increase to this amount befor the full range potential of the
aircraft could be achieved.

Udayan