Expert: Roberto Gomes - 7/9/2008

Question
Hi there!  

I have always wonderd a few things about take off and landing and wonder if you can answer them for me?

1. Why must the lights be dimmed
2. Why must the window shutters be fully open
3. Why do you have to turn your ipod off, but can have it on when in the air?
4. Why do you have to have your seat/tray up (although I am guessing that this is to allow you and the person behind you to adopt the brace position?)

Hope I haven't asked too much!!  

Thanks!

Fiona

Answer
Dear Fiona,

Although this is not my area of expertise, I asked for the help from a captain friend of mine. Here is what I got...

1. One of the main reasons why cabin lights are dimmed during take-off and landing is that in the event it becomes necessary to evacuate the airplane, your eyes are already adjusted. Otherwise, at least several seconds are needed to go from bright light to being able to see in the dark.

2. Another safety issue. If there is any emergency on your side you can see it and then proceed to evacuate going to the other side.

3. The reason why Ipods must be turned off is that they emit radio waves. The navigation and flight control computers on airplanes are designed to sense even very weak signals coming from far away. Radio waves with just the right power and frequency can in theory introduce errors in computing equipment.

4. You're right. Tray tables and seats must be on the upright position to provide space for the person behind you and for the other passengers in your row in case of any emergency. This is the same reason why all carry on bags "must fit completely underneath the seat in front of you", as any bags sticking out too far could create a tripping hazard in the event an emergency egress is needed.

Hope this helps.
Best Regards,
R. Gomes