Concorde1518 From United States of America, joined May 2001, 746 posts, RR: 0 Posted (12 years 11 months 4 days 6 hours ago) and read 4104 times:
Hey guys.... just wondering..
I was on a night flight not too long ago, and I got a cockpit visit after the flight (an A320) and the flightdeck was cold, dark, and all shut down by the time that I got up there, and I was wondering, with all of the systems off, like the battery, APU etc. for the night, what powers the cabin lights, lavs, etc. after all of that is off? Is it the ground power? Also, when the last pax. leaves and the crew is putting the aircraft to bed, what is the process that they go thru to get all of these things turned off?
Bjones From United States of America, joined Feb 2002, 123 posts, RR: 0
Reply 1, posted (12 years 11 months 4 days 6 hours ago) and read 4093 times:
Ground power is usually plugged in before the APU is shut down. Many airlines have gone to plugging in to ground power before the engines are shut down to save on cycles on the APU and gas. When you are done for the night the lights in the cabin are all turned off from the flight attendant station. The ground power can be shut down when the aircraft is unattended.
LMML 14/32 From Malta, joined Jan 2001, 2565 posts, RR: 6
Reply 3, posted (12 years 11 months 2 days 17 hours ago) and read 3825 times:
If by dark you mean the screens it is because the crew have deliberately dimmed them. This extends the life of the tube, I am told. If the cabin lights were still on it means that the aircraft was still powered by the APU or Ground Power. If none of these was on the battery kicks in and the emergency lights go on. On the 320 this provides a lot of light.
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 4, posted (12 years 11 months 2 days 16 hours ago) and read 3813 times:
When the cockpit is dark and the cabin lights are on it means the Ground Service Bus is powering the lights and electrical outlets for the cleaners. This is virtually always powered by the external power system.
There's a switch, normally on the Forward Flight Attendants' panel, to turn this system on. It allows the cleaners to do their jobs without powering (thus reducing the useful life of) the entire avionics suite in the aircraft. Boeing is starting to put the Ground Service Bus switch in the cockpit on some of their aircraft. http://www.b737.org.uk/electrics.htm
The emergency lights have their own battery packs located throughout the aircraft (placement is a function of the manufacturer and customer) and they are mounted on their own integral battery charger bases. If power is on the aircraft and subsequently lost (while the Emergency lights are armed through the cockpit switch) the lights automatically come on and stay on until manually turned off or the batteries die. Depending on the aircraft they are good for 15 to 90 minutes. Some aircraft have an emergency light "test" switch on one or more Flight Attendants' panels so that you don't have to go to the cockpit to test the system or turn on the lights.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
Duncan From United States of America, joined Apr 2002, 131 posts, RR: 0
Reply 5, posted (12 years 11 months 2 days 7 hours ago) and read 3761 times:
Emergency battery pack location is also determined by FAR 25.812 which states that in the event of a single vertical separation of the fuselage during a crash (at any location), no more than 25% of the lights are rendered inoperative, in addition to those directly damaged by the separation.
Also, each emergency exit sign must remain operative and at least one exterior emergency light for each side of the airplane remains operative exclusive of those that are directly damaged by the separation.
You know how I like attention to detail Avioinker.......
B747skipper From , joined Dec 1969, posts, RR:
Reply 6, posted (12 years 11 months 2 days 4 hours ago) and read 3748 times:
Dear Concorde1518 -
The electrical systems of airplanes are "split" in various separate "busses", and many airplanes have something that may bea "cabin service bus" which powers various cabin lights, and electrical outlets which permit the cleaning staff to connect vacuum cleaners. Generally an airplane will not be left "abandoned" with an APU powering the aircraft, without having crew or ground engineers present around the aircraft. Expect an "external power unit" to power the aircraft for the cabin cleaning...