Originally Posted by
Airprox
In the US (reference to the Hudson case), it's 162 nautical miles for rafts and the other survival equipment.
Then you had better tell the FAA
FAR § 1.1 General definitions.
Extended Overwater Operations: (1) With respect to aircraft other than helicopters, an operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline;
and then
FAR § 125.209 Emergency equipment: Extended overwater operations.