FAA approved does not constitute an absolute or a limitation. If you would like, search around for written proof by the FAA claiming that what is in the book is the only way you are allowed to fly the plane, you won't find it. FAA approved only means they approve of the information written in the manual and is different than an FAA regulatory document.

Think of it this way, if you landed an aircraft safely in an emergency situation but didn't follow the written procedures would they rip your ticket? Unless there is also a regulation that says you must follow this FAA approved procedure unless you are in an emergency, I am familiar with no such regulation. Of course my familiarity doesn't mean it doesn't exist, however, if you find such regulation I would love to see it. Thanks and in no way am I trying to sound like a smart ... in this post, if I did, than I am sorry in advance.

Disclaimer: Again I am not promoting any pilot to fly outside of the procedures for typical flights. Instead I only advise every pilot to keep an open mind to any and all procedures, both FAA approved and otherwise. Be open to thinking outside the box and store these procedures, even if they are not published in your books, in the back of your head. Knowing what your aircraft is able to do outside the bounds of those procedures might one day save your butt. Even practicing and experimenting with these unpublished procedures in the sim just so you have them in your toolbox.

Flyingchicken, yes that is interesting, was wondering if someone would comment on that.