In flight rules and procedures
 

If this is the wrong forum to ask these questions I apologize in advance. If there's a better place to ask could someone point me in that direction? TIA

Anyway, I'm what one would call an occasional air traveler, but I have flown a good deal over the years.

Here are some in-flight procedures and regs that I've wondered about for a while.

Why are the procedures at take off such as upright seat backs, curtains opened between coach and business/1st, window shades up, etc.

Another question is about electronic devices. I've been on many flights where cabin instructions are that there is to be no electronics (CD players, computers, game devices, etc.) on til the flight has reached cruising altitude after which use of these items is permitted. However, with that said I just took two legs of an Air France flight SEA-CDG and CDG-TLV and on neither flight was I instructed not to use personal electronic devices.

Now the question about cellphones. We are prohibited from using cellphones at any time once the cabin door has been shut. I've heard different reasons for this. One reason I've heard is that cellphones interfere with the plane's avionics which I'm skeptical of. The other reason I've heard is that the FCC doesn't want people using cellphones on planes because when you're that high up you'll be hitting too many cell sites all at once and possibly you could overload the network.

The general concept is that obstructions to a quick evacuation should be minimized during takeoff and landing because those are the most likely times for an evacuation to occur. Reclined seats, open tray tables, curtains, loose luggage, etc., all make it harder to get out. (Your reclined seat may make it easier for you to get out, but not the luckless person behind you.) Also if there's an abrupt stop, you don't want to get bisected by your tray table.

Window shades are supposed to be open so the conditions outside can be evaluated before an evacuation.

The deal with the electronics is a can of worms that's been debated here lots of times. The main issue is that the possibility of interference hasn't been 100% ruled out, and take-off/landing are the least forgiving of the flight phases. Nobody wants to say "go ahead and use them" and then have a crash.

There are also differences between carriers depending on their particular FAA-approved operating procedures (or between the various governing authorities internationally).

Window shades are a great example...some airlines require them to be up for takeoff and landing, some don't. It just depends on the carrier's specific operating rules.