747 operations from short(ish) runways

Date:         06 Jul 98 03:24:28 
From:         schnabl@mbox.vol.it (Roberto Schnabl)
Organization: Telecom Italia Net
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Could anybody shed some light on heavies' long range operations from
shorter runways?

I am talking about long flights from around 9,000' runways in a 747
like BA's 747-400 from Nagoya Japan (8,990' runway) to LHR, other
examples which come to my mind are the flight which NW used to
run in a 747 from Osaka's older Itami airport (9,843' runway) to LAX
or LH's 747 flight from Duesseldorf (9,843' runway with TORA
restrictions) to LAX.

All flights are or were nonstop and I am intrigued by what takeoff
performances must have been like on a hot summer day in a  nearly
full plane because if payload is very much affected I do not think
the economics would work for the carrier.

I recall one summer takeoff in a fully laden TWA 747 (must have been
an older 100 or 200 series) from Rome Fiumicino' 16R to JFK which
lasted well over 50 seconds: runway is 12,800' and we lifted off just
before the 34L TDZ marking so ground run must have been around
11,500'! Did not like that at all!

On the other hand I also remember transitting Boston Logan in a
LH 747-200 enroute FRA-PHL: as we lined up on 09 (7,000') I was
feeling a bit uncomfortable but we took off in what must have been
no more than a 4,000' ground run (plane was very light though)
therefore performance can change a lot.

I am aware that takeoff parameters are carefully worked out in
a data sheet and are very much dependent on weight, temperature,
weather conditions, runway gradient etc. nevertheless taking off
on a hot summer day in a fairly laden 747 from a 9,000' runway
would give me the creeps.

Obviously if they do it it must be safe, still I am a little bit
curious and would appreciate any comments from people who
really fly the big birds.

Thanks and kind regards

Roberto Schnabl