colossus giant cryptic no 132

Hi, Need some help please.
5 Across. Cite crisis over pans,?r???????s
18 Down.Machinist showing more aptitude,??t?e?
43 Down. Bomb shelter is a trap, of course, b?n???
51 Across. Senior hand worked on frame. ?o???a?
This is the hardest Cryptic. Ta for your help.