Highest Flight Level Actually Flown by a 747
Just trying to win a bet here.
I'm after the highest Flight Level that 747 (SP Aside) has been flown at. I know they are certified to FL 430, but one of my old Flying (USA) magazines says in one article that a Braniff crew on a ferry flight attained FL 510 in a 747-200 many years ago.
I thinks its not true, more like maybe FL 450. Mate swears 510 is true. A few beers a riding on this.