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Mar 7, 2015, 3:46 pm
#586
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We have heard about passengers being restricted from sitting in some parts of the cabin, or having to move before take-off, due to weight and balance - longitudinal balance of the aircraft.
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
Mar 7, 2015, 4:01 pm
#587
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We have heard about passengers being restricted from sitting in some parts of the cabin, or having to move before take-off, due to weight and balance - longitudinal balance of the aircraft.
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
Q: We flew from Miami to JFK on an MD-80. The jet is laid out with two seats on one side of the aisle and three on the other. The question came up: does the asymmetric 3/2 configuration cause any kind of imbalance?
No. Even on a smallish plane like the MD-80 series (a derivative of the even older DC-9), the imbalance is less than negligible. In the cabin, longitudinal balance is a lot more important that lateral balance. But even there it tends to be a minor factor — at least on bigger planes, where the weight of passengers makes up a surprisingly small percentage of a plane’s overall weight. As covered in the first chapter of my book, in the case of a fully loaded 747, the weight of 400 passengers plus their luggage accounts for less than 10 percent of the plane’s total weight.
No. Even on a smallish plane like the MD-80 series (a derivative of the even older DC-9), the imbalance is less than negligible. In the cabin, longitudinal balance is a lot more important that lateral balance. But even there it tends to be a minor factor — at least on bigger planes, where the weight of passengers makes up a surprisingly small percentage of a plane’s overall weight. As covered in the first chapter of my book, in the case of a fully loaded 747, the weight of 400 passengers plus their luggage accounts for less than 10 percent of the plane’s total weight.
Mar 7, 2015, 6:57 pm
#588
Join Date: Oct 2014
Location: London
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The passenger distribution can have some other interesting effects however. I was speaking to a BA FO after a flight back from JER recently, and he said that earlier that day, they'd had to use TOGA (full) thrust for takeoff, rather than a flex (reduced thrust) setting, as the performance calc. hadn't liked the layout of passengers in the cabin.
And this was regarding a flight from I think either EDI or GLA, where even with a much heavier load, you wouldn't usually have to use TOGA for departure. Apparently they were at 2000ft AGL by the time they'd reached the end of the runway. Maybe the A319 thought it was a 757?
And this was regarding a flight from I think either EDI or GLA, where even with a much heavier load, you wouldn't usually have to use TOGA for departure. Apparently they were at 2000ft AGL by the time they'd reached the end of the runway. Maybe the A319 thought it was a 757?
Mar 7, 2015, 11:09 pm
#589
Join Date: Dec 2012
Posts: 3,270
We have heard about passengers being restricted from sitting in some parts of the cabin, or having to move before take-off, due to weight and balance - longitudinal balance of the aircraft.
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
What happens if all the passengers sit on one side of the aircraft? Does it affect transverse balance of the aircraft?
Mar 8, 2015, 1:23 am
#590
Join Date: Aug 2008
Posts: 2,075
Should all the pax sit on one side there would be an effect, but as Sigwx said it is to do with moment arm The centre of "gravity" lies in the centre of the aircraft so the moment arm is low. The ailerons and trim system is more than able to compensate. imbalances in fuel can be more interesting and there are imbalance limitations.
Mar 8, 2015, 5:43 am
#591
Join Date: Feb 2015
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Does anyone know what the small group of lights (usually 3 to 4 of them) that are located in various parts of the cabin - some close to the emergency exits - actually signify..??
My guess is that they're communicating the current status of the aircraft and are placed so that they are visible to the cabin crew from wherever they are...
Wouldn't mind knowing the combination of lights that mean "carry on drinking, everything is fine" and then "we are in deepest, darkest excrement" and my particular favourite "prepare for impact"...
Chris
My guess is that they're communicating the current status of the aircraft and are placed so that they are visible to the cabin crew from wherever they are...
Wouldn't mind knowing the combination of lights that mean "carry on drinking, everything is fine" and then "we are in deepest, darkest excrement" and my particular favourite "prepare for impact"...
Chris
Last edited by Chris_G; Mar 8, 2015 at 5:57 am Reason: spelling...
Mar 8, 2015, 6:02 am
#592
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Do you mean the pink, blue and amber lights that are in the ceiling at all door areas?
Mar 8, 2015, 6:53 am
#594
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Mar 8, 2015, 6:53 am
#595
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The blue light is a passenger call light, the pink one is a crew call and the amber is a toilet call light.
Mar 8, 2015, 7:01 am
#596
Join Date: Jan 2015
Location: UK
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On the A321's the ones at the doors 2&3 display what Seat Row has pressed the call bell on the little screen, as told by a crew member
Mar 8, 2015, 7:40 am
#597
Join Date: Dec 2009
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Should all the pax sit on one side there would be an effect, but as Sigwx said it is to do with moment arm The centre of "gravity" lies in the centre of the aircraft so the moment arm is low. The ailerons and trim system is more than able to compensate. imbalances in fuel can be more interesting and there are imbalance limitations.
Thanks to both of you for the answer (and thanks to all the other BA crew answering in this thread).
Mar 8, 2015, 11:16 am
#598
Join Date: Jun 2009
Posts: 614
On the Airbus, blue is a passenger call bell, amber is a toilet call, green is a cabin crew member call, and red is a flight crew call (except on ex-bmi aircraft where red is both cabin and flight crew calls). On Airbus aircraft if you look around the cabin crew seat area you'll also see a two line digital display showing additional information such as which seat has called, if a toilet smoke detector has activated and so on.
Mar 8, 2015, 11:25 am
#599
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Thanks for that, thankfully I'm not on the Airbus. 
Mar 8, 2015, 1:07 pm
#600
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