91.509 question, ops over water

[stlpilot]

Hey all I Posted this under another topic but no answers yet. Thought Id give this section a try

Anyways Im a bit confused on this reg a student brought it up to me today.

91.509

(a) No person may take off an airplane for a flight over water more than 50 nautical miles from the nearest shore unless that airplane is equipped with a life preserver or an approved flotation means for each occupant of the airplane.

(b) Except as provided in paragraph (c) of this section, no person may take off an airplane for flight over water more than 30 minutes flying time or 100 nautical miles from the nearest shore, whichever is less, unless it has on board the following survival equipment:

So how do I know which one I have to comply with? 50 miles equiptment in part "A" or 30 minutes or 100 miles equiptment in part "B"?

I have a guess at this but it just jumbles in my brain today when I try to reason it, please give me your interpretations and how they apply or a good example might clear my head. Thanks

 

[Flymach2]

Hi...

I'm assuming your student knows that the part you refer to is under Subpart F which is for Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft. It certainly is not my place to question why a student would be interested in this section in the early stages of training, so...

Bottom line is this. If your going to be operating one of the aircraft mentioned above more than 50 NM from the nearest shore but less than 100 NM, you should comply with §91.509(a).

Beyond 30 minutes flying time or 100 NM from the nearest shore, you will comply with §91.509(b). Quite a few more requirements for the latter.

Regards

 

[stlpilot]

Makes perfect sense now thanks.

Its bit deceiving when I say "student", this was a question that arose during a BFR refresher course from a Commercial pilot who flies both corporate and military.