Re: MD80 and ETOPS (and ferry flights)

Date:         20 Mar 97 02:34:56 
From:         tschell@s.psych.uiuc.edu (Terry Schell)
Organization: University of Illinois at Urbana
References:   1 2 3 4
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lstone@interserve.com (Larry Stone) writes:

>In article <airliners.1997.620@ohare.Chicago.COM>, kls@ohare.Chicago.COM
>(Karl Swartz) wrote:

>>Before the debate resurges on how such a plane gets to Hawaii if it
>>doesn't have the range for the trip, there's been much past debate on
>>this point.  See http://www.chicago.com/airliners/archives.html for
>>those old discussions.  Obviously some range is gained by flying with
>>no payload and possibly at slower speeds and/or lower altitudes.

>Higher altitude, not lower. The higher you go, the less you burn. Of
>course, you have to be able to get there in the first place and not burn
>so much fuel doing so that it offsets any gain from cruising that high.
>The decreased burn is so dramatic, UA 757's between SFO and SNA (323
>nautical miles) routinely operate at FL410 (41,000 feet).


The relationship between fuel burn and altitude is more complicated
than your statement implies.  Without getting into details... there
are many instances where lower and slower is more efficient than
higher and faster.  (Going "low and fast" or "high and slow" are both
inefficient)