The tradition to dim lights during landing is a security protocol, but has puzzled many passengers for a longtime. Many think that the action compels passengers to discontinue reading books, using phones and for paying attention. It may also be a simple technique adopted by the airline to ensure scene with the landing of the plane.
However, a pilot revels the inside story and the reason of lights going out during the descending of the aircraft, which is an important safety measure than the apparent reasons. Chris Cooke, the pilot of a major domestic airline spoke to Travel +Leisure Magazine that it was a precautionary step taken to help passengers adjust the vision more rapidly to darkness. It may be required in an emergency landing and immediate evacuation of passengers in the event of an unfortunate happening. He further added that in a situation when people in a bright room with many obstructions and suddenly lights turned off and people are required to make fast exit.
Passengers are also requested to leave blinds up during landing for the same reason. Clear windows bring in natural light for help when inside lights are suddenly switched off.