Originally Posted by
Mr Mac
Teeteringahead
You should have seen the Brown Stains down the back of long haul 747 back in the smoking era. Always at the back of A/C towards the end, though before that it was common all over A/C. I did a flight down to Santiago in early 70;s with a Cuban cigar smoker next to me, I was 14 at the time, and smelled Smokey on arrival apparently to my parents.
Cheers
Mr Mac
Mr Mac,
Those brown stains came from the outflow valves...and if you think they were bad, you were fortunate in not having to replace an outflow valve covered in tar.
The, unintended, side effect of smoking on board was this helped identify failed rivets / fasteners because there was a visible little brown streak around the edges.