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A personal flotation device (PFD) required by 14 CFR 91 shall be worn by each individual on board the helicopter when conducting operations beyond power-off gliding distance to shore, and during all hovering flight operations conducted over water sources such as ponds, streams, lakes, and coastal waters.

If the requirements were that either a power off glide distance or flight over water required a PFD, shouldn't "or" be there?

Does the use of "and" say that both elements, beyond gliding distant and over a water source must be in place to require a PFD?

Is the "and" acting as a "while" since it connects both parts?

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closed as off-topic by MετάEd, tchrist, p.s.w.g, Kris, TrevorD Jul 16 '13 at 23:18

  • This question does not appear to be about English language and usage within the scope defined in the help center.
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Yes, it means in either situation, and no, it does not have to be "or". (I'm not sure where you got that notion from. If I like pizza and pie, I can say "I like pizza and pie", without implying that I stuff my face with both simultaneously.) In fact if it did imply "both elements must be in place", then you'd just omit and from that sentence completely and leave it at during. (In other words, the and cannot be acting as a "while" in there, because you already have during acting as that.) – RegDwigнt Jul 15 '13 at 21:28
Per our help center, requests to interpret/analyze the meaning of a specific text are off topic. It is especially not a good idea to ask this site for interpretation of legal codes, because legal interpretation is full of special cases and special rules that don't apply anywhere in English. – MετάEd Jul 15 '13 at 22:06
I would call this general reference: The use of and*/ *or should be clear to any one reasonably good at reasoning. – Kris Jul 16 '13 at 6:34

It does not say that both elements must be present. It lists two circumstances in which the PFD must be worn:

  1. When conducting operations beyond power-off gliding distance to shore
  2. During all hovering flight operations conducted over water sources such as ponds, streams, lakes, and coastal waters

Basically, it says, “The PFD must be worn in situations A and B”. If it had said ‘or’ instead of ‘and’, it would arguably have meant that during a hovering flight operation conducted over a lake, but also beyond power-off gliding distance to shore, the PFD is not mandatory, since not one or the other condition is met, but both of them at once.

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