The really short answer is to reduce potential risk of interference, after all any CE marked and EMI compliant transmitter (eg- cell phone, laptop with wireless mouse, etc) is still a transmitter.

Now days it is allowed to use many different electronic devices on planes (including cell phones set to 'flight mode' or similar), but not during landing and takeoff.

after all any CE marked and EMI compliant transmitter (eg- cell phone, laptop with wireless mouse, etc) is still a transmitter.

My point is more regarding equipment used in aeroplanes.

One one hand the equipment we use (like cell phone, Laptops etc. are CE amrked. Thus they are supposed to be non interfering). But we may assume that all equipment in the plane are not CE marked, as passengers may be from any country, where these regulations are not stringent (or even non existant)

But more on the other hand the equiment being used for aeroplanes should be CE marked. Means they should not get affected by any radiation from other equipment.

Are we not sure about the reliability of equipment used in aeroplanes?

The CE mark does not mean (guarantee) that the equipment is non interfering. The mark means that the emissions are at or below the level specified in the test. This will do a good (but not perfect) job of preventing interference with your neighbor's consumer electronics. The proper operation of the navigational aids inside an aircraft are "life and death" where the proper operation of your neighbors electronics is not.

Also, any equipment with a malfunction or damage might have emissions beyond the level specified by the CE mark. The mark does not mean that this exact piece of equipment is emitting at or below the specified level. The mark means that the design passed and all equipment should pass when it leaves the factory. That is not an "aerospace quality" level of confidence.

Excellent reply, correct in all regards.

emc_c

I agree completely with you. All these facts I know already being working in the field day today.

Besides, I would like to add that recently directives are diluted by making EMI/ EMC third party certification non-mandatory. One can self declare the equipment as EMI /EMC compliant.

My point is why Aeroplane manufacturers can make navigation equipment immune to EM radiations? If they are good designed emmune equipment, we need not bother about the quality of all equipment being boarded on the plane by all passengers.

If the aircraft electronic instrumentation is redesigned to be immune, it will likely require that all sending and recieving equipment be changed into a dual format design until the older equipmnt is phased out. Monumentally huge costs involved when done to aviation standards, just like the military; will it still work while strapped to a submerged paint shaker at 900 degrees on just battery back-up? The lead time from design to market would likely be a decade, and then there would be the retro-fit issues to deal with.

Aviation upgrade approvals and standards change very slowly because of these costs.

" why switching off electronic equipment is necessary."

Because, it's their airplane!

I agree. It is probably the case that the electronics ban is just the airline's rule.

After all, if you've ever taken off from Logan, it's obvious the two big safety concerns are:

WHO THE $%%$#* THOUGHT IT A GOOD IDEA TO BUILD A BAY IN THE MIDDLE OF A RUNWAY?

and,

Why do airport taxis have a statue of St. Jude and a next-of-kin form in the back seat?

All the electronic equipment built into the aircraft must be EMC compliant, but the flight safety depends on a lot of external radio interaction such as, instrument landing system, radio altimeter, direction finders receiving beacon signals, radar transponder, radio, etc. If your electronic gizmo is radiating on or near any of these frequencies it could cause interference and affect safe operation. This is especially important during landing when RF reflections from ground features are also affecting the signals.

Best to switch your gizmo off and concentrate on the cabin environment during the landing - you might need to get out in a hurry!

GA.

I get convinced on your answer to my doubt.

I'm guessing, but it may well be that this ruling has nothing to do with any signals emitted by the building or any equipment in the building, but rather with the building physically blocking the signals required for the instrument landing system. Instrument landings require a shallower glide path, and planes must be able to receive the signals both on and, within limits, off (which may include above and below) the correct trajectory.

The building may block a critical region for the airport terminal control airspace radar so the controllers can't see what's behind it. Electromagnetic reflections or shadowing of glidepath or other navigational signals by the building would also be bad news.

Worse yet, the building could be right in the way of the flight path to the runway (you could call it mechanical interference). It's bad enough to have maniacs with evil theology threatening to fly planes into skyscrapers without setting up accidents waiting to happen...

In other words, the FAA was concerned about hazards much more serious than the electronic toys inside the building.