So yesterday I was on a half empty flight from Edinburgh and before take off the bloke sat in front of me who was way over 6 foot and crammed into the middle seat of three, all occupied, looking extremely uncomfortable asked the air hostess if he could move seats to the empty row in front
She said no as the plane was ‘balanced for take off’

It looked more like a pretty random splattering of occupied and unoccupied seats to me

He was only asking to move one row forward, is it really that critical? (I doubt it, just a grumpy air hostess) and if it matters how do easyjet etc with unallocated seating cope?

Got me thinking though, if everyone on a half empty flight sat at the front/rear or all on one side of the plane, would it not be able to get off the ground? Would it have any effect?
What if mid flight everyone got up and ran to the front of the plane?

Can anyone put my mind at rest before I have to fly again 😉

What if mid flight everyone got up and ran to the front of the plane?

Wasn’t there a story in the news recently about a crocodile escaping from the cargo hold of a plane ?
Everyone ran forward to get away from it and the plane nose dived in to the ground with no survivors.

I suspect you don’t have to balance them that accurately, but I was on a half empty EasyJet flight from Bristol to Edinburgh las week, and the cabin crew made a point of trying to spread everyone out throughout the plane – never noticed it before.

Here we are.
http://www.google.co.uk/search?aq=f&sourceid=chrome&ie=UTF-8&q=crocodile+plane+crash

The crocodile survived. So much for evolution they were built to survive plane crashes before planes were invented.

If they had to balance the plane that accurately then they would need to weigh each passenger before they boarded the plane.

They don’t.

Its true that aircraft haved to be trimmed during flight for weight changes but this is due to several tonnes of aviation fuel being burned off rather than whether one of the passengers moves seat or has a dump before they board

Depends how big the plane is. A single passenger moving a couple of rows on an A380 would make not a jot of difference, but try it in a Cessna and see what it does to the handling.

There was a crash in the states a few years back due to poor weight distribution – been on Discovery channel “Air Crash Investigation”

richmtb – Member
If they had to balance the plane that accurately then they would need to weigh each passenger before they boarded the plane.

Not really, it would average out.

But, as said above, on a commercial airliner, the plane itself is heavy enough for this to be a lot less important than for a smaller/lighter one.

As an ex baggage handler one job we had to do now and again was to place ballast on the BA turboprop planes. The captain probably has a seating plan and the hostess would not want to deviate from it (plus I think that during take off and landing they want you in your allocated seat)

I can remember 6 of us sitting on the very back rows of the 20 seater jalopy that flies Southampton – Gurnsey. I asked why we were all sat at the very back with all the empty seats and was told there was an technical fault and the plane wouldn’t take off with much weight ahead of the wings.

Not very reassuring but I slept through the flight anyway

What John said depends on size of aircraft,
one other thing to factor in which I have been told is that in the unlikley event of the aircraft becoming a smoking hole in the hill side, knowing were everybody was sitting can aide in identification. How true this is who knows but sounds sort of plausable to me.

Yup, size of aircraft, anything bigger than 50 seater and it will make naff all difference.

If 50 passengers move significantly from their assigned seats then it will have an effect on the balance of the aircraft – in effect you’re moving over 4 tonnes of freight about the aircraft. It’s generally only an issue on a lighter aircraft, by that I mean an aircraft that is fairly empty, but the c of g needs to be within prescribed limits, particularly for take off. Most a/c have fuel tanks very close to the c of g, so the effect of fuel load/burn is fairly small
What is total rubbish is the idea that it aids identification after an accident!

I believe that on bigger aircraft fuel is pumped around different tanks automatically to “balance” the C of G as people move / fuel gets burned etc.

Certainly as stated on smaller ones they need to balance people – it’s happened to me a few times on a small half-empty plane out of City (which is a flipping white knuckle ride at the best of times – utterly terrifying landing in a high easterly wind!!).

Generally fuel isn’t pumped around the a/c for balance, except for larger a/c.
All that really changes is the amount of lift/downforce generated by the tail. It’s best to have an aft c of g, so that the tail produces lift.
If the c of g is too far forward, then the tail produces a downforce to balance the a/c. The wing then has to produce more lift to compensate, which means more fuel burn, which costs money etc., etc.

Its true that aircraft haved to be trimmed during flight for weight changes

The aircraft is trimmed before flight. If you are out of trim, the aircraft will be nose or tail heavy. This could result in something as extreme as failing to take off if you got it so wrong, or lifting too early if you got it tail-heavy. Trimming before flight ensures the operating crew have the load (including fuel load) within their operating parameters for that sector.

So yes – distribution of passengers can be critical, but probably not that critical. However, the cabin crew don’t make those decisions and probably have broad ‘standards’ for seating ie nobody forward of a certain row. Safety margins are large in aviation, for very good reasons.