1) when you are in Overheat condition
2) The sonarman is NOT in a support position. (will not work in gunner position).
or
Your sonarman is weak and the range is shorter than the sub that sees you and whom is firing torps at you. You then hit the gas and the sonarman's ability is turned off. You never saw the sub.
Of course you could be distracted on a bombing mission and not see that red dot on the mini-map before he slams a six-shot salvo into your belly.
I find it inconceivable that NFNA would remove sonar ability from CVs. If anything, they're more inclined to give to all surface ships, not take it away.
