How often was a sub attacked by aircraft on patrol?

[seafarer]

In real life, I'd think you'd also want to dive as soon as getting an SD radar blip just to avoid being seen. Why have all the surface traffic in that area alerted to the presence of a sub? Then you just have to waste fuel moving to a fresh area, or chasing down zig-zagging targets and such.

Better to remain unannounced until you put a torpedo into something