Did the colour system start on the Caravelle??
'twas on the Comet green,blue,yellow and red.
One was in deep do do if all you had was red !
Didn't the Carvelle use Comet systems (and nose)? We have a Nimrod MR2 at Manchester and that has green,blue,yellow and red systems, being basically a Comet 4!
I understand Concorde was to have these 4 systems as well, but the Red system was deleted early on.