I have been on many flights where wing vapour trails can be seen
from inside the a/craft .It seems to happen where the air is very
moist eg UK, Miami FLA, Barbados etc .Also starts at/below
10,000 feet and how much flaps/air brakes are applied as well
as how much ailerons are in use and air speed .Sometimes on a wet
day in the UK, these vapour trails are visible at the point of
touchdown - squeezing the moisture out of the air - some of the
following I think are relevent : Altitude, speed, humidity, Air
brakes/ flap settings (which create Hi/Lo pressures around
the wing) and more that some of you 'boffs' can add

jrm

On Wed, 23 Jul 2003 21:23:13 +0000 (GMT), Rodney Blackall
wrote:

In article , Keith Chaplin
wrote:
Yesterday(Monday) a Hercules flew over Beccles, west to east, not very
high (c5000 ft?) leaving dense, persistent wing tip trails. I've never
seen this before.

I have (not a Herc.) but it was dumping fuel. So where are the fuel dump
ports on a C130 anyone?