# Why aren't we weighed before boarding an airplane?

Why aren't we weight before boarding an airplane? ?

I know airplanes have a certain weight maximum. How come passengers and their carryon luggage isn't weight prior to boarding.

Also, how do planes balance themselves if you have 1 row with 2 seats to the right and 3 seats to the left and people walking around??

Relevance

Each airplane has a COG (center of Gravity) Envelope, The Equipment, the actual aircraft, and things that stay on the plane are calculated into the initial weight. (i.e seats, computer equipment, even the coffee pot's). For each passenger there is an average weight for adults and children (this is why the airline keeps a count of how many kids are on the flight.) The cabin of the aircraft is broken into "Zones".

A break down of how many passengers seated in each zone is then calculated into the COG. Checked luggage is also averaged out in weight, except with bags that weigh over 50lbs, then the actually weight is taken and added to the calculation. The larger the Aircraft, the larger the COG envelope is, and so the smalled the aircraft is the smalled the COG envelope. This is why you may see passengers being moved around on smalled planes but are less likely to see that happen on the larger planes. Also with smalled planes the cargo hold is typically in the back of the aircraft while with the larger planes the cargo holds are under the aircraft also spreading the weight around between the "zones".

As for the make up of the cabin, two seats on one side and three on the other, it does not matter because the wings are going to stable the aircraft out. The key is to make sure the weight is distributed between the noes and the tail putting it into the COG envelope.

It would be extremely costly for the airlines and extremely time consuming for passengers. Check-in times would be far longer than they already are. And, there is no need for it.

Airlines simply use an average weight per passenger. It is extremely unlikely that a random group of 100-150 passengers will collectively be far heavier than normal. If flights average out to a certain weight per person, then it makes more sense to use the average than to spend the time and money to weight everyone individually.

The US Federal Aviation Administration requires airlines to assume an average weight of 200 lbs each for men and 179 lbs each for women, including carry-on luggage.

Pilots of small, private aircraft may ask their passengers for their weight because a group of 3 or 4 people may be heavier than normal. I've even seen passengers moved around on a 20-seat aircraft to balance it out. The rules of statistics don't apply to such a small sample.

Source(s): International Aviation Safety Association website
• Steffi
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