Concorde operations have always been subject to dubious accounting.........We can't have the flagship obviously leaking money in a similar fashion to its ability to leak fuel.:o
One figure that may be of intrest....... No. of Engineering manhours per flying hour......
Locheed Galaxy (perhaps the militarys most un-reliable a/c ) 22
BA 747 Between 9 and 11
BA Concorde 42 yes thats right forty two !