Ditch Switch . . . does it actually help?
The A320 ditch switch . . . er ditch button as it actually is . . . may have little effect on the outcome of alighting on water.
Examination of the underside of 1549 shows large leak paths in the 48 Section. The holes are bigger than the combined size of the outflow valve and inlets that would have been closed if the button had been pressed. I hope that the NTSB report concludes that the ditch switch (it does sound better than button) disuse in this incident had no impact on survivability.
Others have thought that its primary benefit is to prevent deicing material from entering the cabin.
Should a crew in work overload conditions be expected to use it?