Only 1 time. This happened quite recently, where a 'flock' of German aircraft attacked an enemy ship (Sergbuto's Transport). It occured maybe 2/300km from home base. I was setup to fire a torpedo when they attacked (submerged, and quite close to the enemy ship!).
It happened while based at La Spezia (29th Flotilla), early-1942. I'm not using any AC mods, etc., so it was a 'stock' SH3 plane-attack. I didn't radio-in any report. They just showed up and attacked.
Btw they were really bombing hard, but didn't sink the ship right away (lousy aim maybe?). They may have but a torpedo got it first. I should have waited to see what the German AC would have done.
Otoh, I have lots of strange problems, just 'getting' (or staying) transferred to the 29th flotilla. Figures it happened there...
I doubt I'll see this again. Was neat though!