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When landing at night on most planes they say that due to safety regulations the lights will be dimmed and if you want to continue reading you can use your overhead lamp(it could be that this only happens in Europe I am not sure). I wonder what is the reason for this? What safety does dimming the lights add?

marked as duplicate by Giorgio, Community Jun 28 '18 at 11:32

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Dimming the lights allows your eyes to pre-adjust to darkness, so that you're not suddenly blinded if something happens and the power goes out, and you are trying to find the doors in darkness or smoke. In addition, the emergency path-lighting and signs will also be more visible. And it makes it easier to see outside, which helps you to maintain at least a basic sense of orientation - i.e. which way is up. Raising your window shade during takeoff and landing is also part of the same strategy.

  • Very interesting point, I have always thought they mean it makes it safer to land for some reason. I never considered it is to make it easier for you to cope with an emergency – Ivaylo Strandjev Jun 28 '18 at 6:13
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    Isn't it also because it makes it easier to visually see any possible problems with the wings or engines during or after landing (smoke, fire, breakages, etc.) - the same reason that the windows shades have to be raised. – Erwin Bolwidt Jun 28 '18 at 9:17
  • @ErwinBolwidt: not terribly much, when something goes wrong the pilots most of the time have a good idea of what is wrong, and the majority of passengers would only be able to say "there is some part of the wing missing", which doesn't really help; not to say that getting that information into the cockpit most likely takes longer than any necessary countermeasures. In case of evacuation the crew may easier spot which emergency exits are the best, though I bet that a possible fire is easy to see anyways ^^ – PlasmaHH Jun 28 '18 at 10:52
  • @PlasmaHH Erwin is correct, ask any member of cabin crew next time you fly – Gaius Jun 28 '18 at 11:22
  • The (semi) scientific rule of thumb is... it takes 30 seconds for your sight to adjust from complete darkness to daylight (or artificial light), and it takes 30 minutes for you sight to transition from light to dark. – BDLPPL Jun 28 '18 at 11:29

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