An old thread about an air crash ( a short time after take-off and while the plane was trying to fly back to the airport) :
Gabon Express crash
My (ex)co-worker, who was in that plane, survived.
He "only" spent two hours in the water, before being rescued.
Had this happened at dusk/night, a waterproof or at least water resistant flashlight for signaling could have been a real life saver.

EDC what you can... you never know what will happen, what will come handy... or more than that !

(OTOH a kitchen sink would NOT have been useful, in those circumstances)