I can definately assure you that air platforms will have a MUCH more difficult time finding subs unless there is a ship linking its TA contacts nearby and the reason to be deep is that the thermal layers will probably be much more useful at the extreme ranges of buoys and dipping sonars.
I was dipping 3nm from the Gepard and NOTHING NADA no contact. My FFG picked it up at outside 5nm or so (it was a test scenario not looking specifically at that).
Edit: there is no improvements in passive performance, it is all relative to the sound levels being drastically reduced.
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LW

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