14 CFR § 136.11

A rotorcraft used in commercial air tours over water beyond the shoreline must be equipped with fixed floats or an inflatable flotation system adequate to accomplish a safe emergency ditching, if—

It is a single-engine rotorcraft; or

It is a multi-engine rotorcraft that cannot be operated with the critical engine inoperative at a weight that will allow it to climb, at least 50 feet a minute, at an altitude of 1,000 feet above the surface, as provided in the approved aircraft flight manual for that aircraft.

Each rotorcraft that is required to be equipped with an inflatable flotation system under this section must have:

The activation switch for the flotation system on one of the primary flight controls; and

The flotation system armed when the rotorcraft is over water beyond the shoreline and is flying at a speed that does not exceed the maximum speed prescribed in the approved aircraft flight manual for flying with the flotation system armed.

Neither fixed floats nor an inflatable flotation system is required for a rotorcraft under this section when that rotorcraft is:

Over water only during the takeoff or landing portion of the flight; or

Operated within power-off gliding distance to the shoreline for the duration of the flight and each occupant is wearing a life preserver from before takeoff until the aircraft is no longer over water.