Back in 1991 when only a few privileged people had cell phones, this rule was passed over concerns that the radio waves emitted from a cell phone could interfere with more important radio transmissions such as communications between Air Traffic Control and pilots so that your plane can avoid obstacles like thunderstorms, mountains, and other planes.
Later on as other types of devices like portable audio and video players became more widespread there was further concern that even devices that did not transmit data over the air could interfere with critical airplane electronics like Positioning Systems etc. In fact, one passenger’s handheld DVD player caused an instrument in a cockpit to indicate the plane was pointed in the opposite direction in an incident in 1999!
Modern aviation electronics or ‘avionics’ resist interference far better than they used to and on top of that, there has never been any definitive evidence linking portable consumer electronics to an actual crash. In response to this reality rules were a bit relaxed about exactly when passengers could use their gadgets in 2013 and since then some flights have been allowed Electronics use throughout the flight, even below 10,000 feet! Previously which was banned because takeoff and landing are the most dangerous segments of flight where lots of things need to happen with precision in a particular order for safe departure and arrival.
The new rule only allows the use of non-transmitting devices so while you can use an MP3 player to listen to songs that you have saved to its local storage and you can forget about a voice call on a cellular network. Hence, the famous airplane mode that stops all transmissions from the device came into the picture.
But why such thing is even there when specific frequencies are allocated to cellular connections to reduce the risk of interference with flight. Surprisingly in Europe, passengers are allowed to use their cellular data it is just calls that are banned and that too only to avoid annoying other passengers. This rule could be a case of government regulators filling pockets of companies who want to charge people for in-flight communication services! Still, the airplane mode is quite a good thing.
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