HC
I accept that this adaptation wouldn't be straight forward but, given the circumstances, more than worth pursuing.
The main point really is to see this as an approach mode and not a landing one. If the primary alert trigger is an excessive rate of descent once deemed in the approach phase then databases of deck heights etc are not an issue. Onshore, the approaches are in part covered and protected by the ILS mode. Does the CAA/EASA mandate this for fixed wing?
I agree wholeheartedly that robust SOPs are an essential part of creating a safer environment in which to operate. However, having an SOP is one thing, always and strictly operating to it is another.....
Adapting the TAWS, using available technology, would provide a last line of defence when, for whatever reason, an aircrew find themselves near the surface and in difficulty. This I believe was the original intent of the 100' call.
It's a pity that Honeywell aren't on board. Perhaps they can be persuaded.
If I was flying a computer that had the capacity (?) to warn me that I was approaching the water very quickly, (and, crucially, at a point where the aircraft still had the capability to fly away), shouldn't I and my passengers be disappointed, (understatement), that an alarm is not generated ? (Though the event is perfectly recorded!)
The 100' call was perhaps appropriate to the technology at the time its usefulness became apparent. Modernise......
Marc