Dim Cabin Lights on Take Off

[alasdair_cook]

Why oh why do they dim the cabin lights on take off in airliners?

Two schools of thought we're having here:

1: As part of a legal requirement so passengers eyes are adjusted to the dark so they can see the emergency exit lights....
2: So the electrical load is reduced on the engines, thus creating a redundancy for a single engine failure.

Please help!

thanks!

[Captain Stable]

Lights are one of the lightest loads on generators.

The main reason is so the crew's eyes are adjusted to the dark as well as the passengers', and emergency exits and details outside the aircraft are more easily visible in the event of problems. Hence also the reason for window blinds needing to be open for takeoff and landing.

Hope this answers your question.

[AEUSkinner]

We dim the cabin lights so that in an emergency and we have to evacuate the passengers they don't have to adjust to the darkness outside and can go right down the slide and away from the aircraft.

[*Lancer*]

AEUSkinner, sounds good but in practice the slides are generally floodlit :)

[Deep Stall]

To add to Captain Stable's response:

In the event of a dark and/or dense smoky cabin,it allow's the passenger's a better view of emergency lights in the cabin floor,leading them to the exits.
Quite important as it seems in many narrow-body airliner's these days that said lights are usually halfway under the 'C' seat! :uhoh:

[AEUSkinner]

Lancer, I wouldnt exactly call them flood lights, they have lights on them that may or may not come on but the main purpose is so peoples eyes do not have to adjust too much to the darkness outside

[Biggles' Apprentice]

Rather morbidly, also allows emergency services to swiftly determine any cabin fire positions....

Sorry, but true.

[OzExpat]

And then, as part of the same PA about dimming of lights, SLF are told that they can use the reading light if they wish...

[Capt Claret]

Alasdair,

Any tubine multi I've operated has had ample electical capacity after the failure of an engine/generator without having to shed lights.

[av8boy]

And then, as part of the same PA about dimming of lights, SLF are told that they can use the reading light if they wish...

...and continue to do so because the number of actual evacuations is so very small that natural selection never has a chance to kick-in. :\

Although I understand that the sort of time frame we're talking about here is generally not enough for one's eyes to actually dark-adapt, I, for one, will accept any tools offered when it comes to getting my carcass out of the airframe alive.

I'd like to see a study which correlated individuals who turn on their reading light when the lights dim with those who stand up and pull their 50 pound bags out of the overhead during moderate or better turbulence, and those who take their seat belts off during taxi-in. Grrrrrr.

Dave

PS The new spell-check is really delightful. Thanks Danny!

[Trislander]

It is not every airline's policy to open blinds for t/o and landing.

The purpose is more for getting the eyes adjusted to the emergency lighting than seeing outside - natural instinct tells a person to run in the opposite direction to the burning aircraft!!

The light dimming procedure on the Dash 8 for example isn't actually that effective.

The light dimming procedure is also not a rule, just a recommendation, hence pax may continue to use their individual reading light if they so wish. It takes a good 20-40 mins for your eyes to produce the chemical required for nightvision so it is not necessarily that effective, but that is not the point.

T=