Well guys, when I was for Air Canada, .....I was a tank sealer for a certain period of time. Beleive me, I went in fuel tanks quite a few times. We were doin' "negative checks". So, we were makin' vacuum in the tank,........spray some dye liquid outside the suspected wing surface area. Then, we were goin' into the tank, crawlin' like rats with a light, ......and could see the signs of leaks. We never missed the target!!...............we were "tank sealers"
We were the guys who could fix the problem!!! Give me $ and I'll fix it!!!