On Sun, 16 Oct 2011 10:03 +0100 (BST)
lid (Paul Cummins) wrote:
How strange - an Afterburner is very clean, as it superheats and burns

Actually an afterburner just dumps more fuel into the exhaust of the turbine
which then ignites with the left over O2.

the fuel almost completely. Certainly the only film of Concorde I can
find with a trail of brown smoke is the day it crashed.

You didn't look very hard. This shows it quite nicely:

http://www.youtube.com/watch?v=m0pCWn3qLyI

Skip to 2:55 for the full muck.

B2003