why are the cabin lights in the air-crafts are switched off while take-off and landing?

Question

Normaly the passengers' cabin lights would be switched off when the air-crafts are landing and during take-offs. What is the reason behind this action.

Answer 1

"Why are the lights switched off and the window shutters opened during take-off and landing?

At SN Brussels Airlines safety is a key priority, and all areas of operation we take preventive safety measures very seriously. While these take-off procedures may appear banal, they are actually quite important. Firstly, when the lights are dimmed, passengers eyes get used to a low level of brightness, and so in the event of an evacuation they will be able to see better in the low-level emergency lighting.

Secondly, the window blinds are kept open during take-off and landing to give better visibility, both from the inside out and vice versa - this way in the case of emergency both the crew and an eventual emergency team outside the plane can see what’s happening and make more informed decisions."

Answer 2

It really depends upon who you fly with, and their operation procedures. There is not an FAR rule that mandates the lights to be on or off... power has nothing to do with it, as the generators that run off the engine.. are designed to handle the capacity of all power consumed on the entire aircraft. One of the main reasons for turning off the light, is for the customer (or passanger) so they can see ouit of the aircraft easily. Just like when you are driving down the road and you turn a light on... it is hard too see. The air carrier is there to provide their customers with a good experiance... within reason. It also calms passengers down, and helps them to relax.
The APU (which I am a tech rep for) Is used for a couple basic reasons, it is used while on the ramp as a low fuel burning generator so they can run the ACM (Air cycle machine) to keep the cabin cool or warm. The APU is also used to help start the #2 engine (as most people start the #2 first, as on corporate jets... the entry door is located on the LH side or #1 side, and the noise from the #1 engine makes VIP very unhappy... but if they have an APU they can run this while waiting for the VIP or passangers to get on board.. allowing usually upto about 300 amps (Honeywell 150) continuos, and most APU's are turned off before flight, and not used for the diration of the flight. . The lights in the cabin, depending upon whatt hey use, (if it is SELA or ALC lighting) they will only draw upto 10 amps max ... if every light is lit. If they use LED lighting it is far less. The stress put on APU is very minimal and in the event of electrical failure, load shed comes into play. All non-essential bus power is shed, and the only essential power is left. There is emergency lighting that will come on, and this is typically ran off of a emergency battery.... not generator power.

So all in all, the lights beign on has nothing to do with too little power given to the pilots. As stated before if there is a problem, the pilot can deselect cabin lights, or in the event of bus failure (a bus is the term for the power source, and most aircraft have many different busses, from primary, secondary, essential, and non-essential) and the contactors that control where the power goes will shed (turn off) all non-essential items.

Also the engine run off of fuel, and the pilot controls how much by utilizing the throttles. More power needed? Okay push the throttles forward. The genereator on the engines (and APU as this is typically a small turbine) puts out a constant voltage (tipically 28VDC) and has many circuits to monitor and control the output current... If more current is required by the load, then the gnerator will increase its output by increasing RPM... and reduceds the life of the brushed on the generator, however if you over load the generator you will get an indication in the cockpit such as a "caution or Max" light. This gives the pilots and indication they have too much draw on the generator. These lights you would typically only see come on the APU and not typically the main generators. Anyway, I have been a tech rep for the Duncan/Garrett APU that is installed on G100's, Cessna 650's, sabb 340's, and Falcon 20's... and also manage an installation shop... where we install those cabin lights... and everything else that runs off of power...

Answer 3

During Take-Off & Landing cabin lights are switched off due to the following reason:

Take-Off & Landings are two critical activities when all the intruments should be 'ready' and keep on working in a systematic way. This is called 'Redundancy' in electronics. That is if one computer or a system fails the backup computer starts working after a 'switchover'. All these backups (i.e. computers) require a lots of power to keep on working. So switching off the cabin lights makes the APU(Auxillary Power Unit---it is just like an inverter we use in our homes as a backup power source) capable of providing continous power to 'main' systems, in case of an emergency. To summarize, the APU shouldn't trip beacuse of this overloading (cabin lights).

Answer 4

Just like Lady said, it's all in the name of safety. Hopefully it never comes down to needing to see through the windows in order to get in to rescue passengers, but the trained professionals will never gamble with safety and take this seriously.

Answer 5

the reason for this is for take-off they need as much power as possible and for landing too

Answer 6

I would think this is because any lights would cause a glare, thus making it diffucult for the pilto to see where he is landing.

Answer 7

My guess is to dim people's alertness during high stress times.

Answer 8

2 save power i suppose