Why is it that, as far as I can see, every time someone asks a question or for advice, about the operation of an aircraft, most people simply jump in with their own favourite method, list, etc? Surely when a specific question is asked the correct thing to do is point the enquirer in the direction of the POH?
Perhaps because there's more be discussed than simple "read your manual." Perhaps because one might learn something by expanding on the topic, rather than simply "read the manual." Perhaps because there's more to the subject, than simply "read the manual." Perhaps becuase the manual isn't always comprehensive enough to address the topic, perhaps because occasionally the manual is wrong, perhaps because occasionally one may not encounter exactly what is spelled out in the manual. Perhaps because when one encounters the problem, there won't be time to consult the manual...but there's plenty of time to discuss the situation now.
I've had events occur in the airplane that weren't in the manual. I went to school for one type airplane after a year of flying it; in that recurrent class of eight, we were queried as to what emergencies and abnormal events we had experienced in the past year. Between the eight of us, we'd experienced everything in the manual, plus a number of events which weren't.
Several years ago while flying a foriegn airplane with a flight manual written in a foriegn language and poorly translated, and then only translated in part, I experienced an aerodynamic control lock, extreme buffet and vibration, and inability to control the airplane, within the published numbers that ought to have been considered "safe." This certainly wasn't in the book (which was prefaced by a sticker on the cover that said in essence, "nothing in this book should be relied upon or believed." I kid you not). Nor would there have been time to look it up, assuming it was readable or translated, when it occured. Three of that type have had inflight wing separations...nobody had any time to look it up then, either...and it's not in the book to look up even if there were time to do so.
A common discussion regarding light airplanes involves Cessna's recommendation against slipping with full flaps in the 100 and 200 series airplanes. All sorts of wild ideas abound, compounded by the fact that Cessna doesn't explain the reason in the flight manual. Most who expound on the subject don't have any idea why, but come up with some wild guesses. A discussion on the subject doesn't just address the subject itself, of course; because background and understanding of the aerodynamics involved are important...it benefits the listener beyond a simple "read your manual." And so it should.
Captain Al Haynes had never received training on, or read any papers discussing, nor found any referrences in his Aircraft Operations Manual regarding a complete control loss and full loss of hydraulics, when it happened aboard UAL 232. Never the less, on board was an individual who had developed his own methods for handling the airplane in the event just such an occurence ever happened; he came forward and volunteered what he'd learned in his studies, and the result when putting it into a crew coordination situation was that a lot of lives were saved. Again, not the manual, but fully deserving of much deeper consideration than just "read your manual."
Cessna has included the Fuel Flow Fluctuation procedure in their 200 series Cessna manuals for some time now, but the procedure is wrong, completely overlooks the chief cause of the problem, and using the procedure in the book can result in an unrecoverable engine stoppage, instead of a quick and painless power restoration.
I've flown several aircraft that were so heavily modified that reference to the aircraft flight manual was utterly worthless for any understanding of systems, performance, or procedure. In fact, one type differs enough that it's difficult finding two of the same type aircraft that are similiar enough to compare one to the other...from radial to turbine power to vastly different fuel, hydraulic, electrical and other systems on board...they don't even fly the same, perform the same, or handle the same, let alone work the same...discussions therefore should justifiably go beyond "read the manual."
It may save your life, or it may just help you come to understand your own airplane a little better. It's certainly worked for me.