Plastic:

The CG of an airliner is determined by using a loads form. On this form the weight and moment arm of the plane, passengers, cargo, fuel, etc. are all added up. The position of the resulting weight/moment index is then plotted on a diagram of the CG envelope. Standard passenger weights are used and vary depending on the time of year (heavier in the winter). Standard weights are also used for luggage. Bulk cargo has to be weighted individually. Standard weights for unussual loads such as a football team charter are of course diferent to those of regular passengers.

The whole process of preparing this form by hand takes all of 5 minutes. For larger airplanes, the process is often computerized and performed by a loadmaster at the station, although doing it by hand is still not that big of a deal.

Airliners have very wide CG ranges to accomodate all kinds of loads. Also, if one section of the airplane has more passengers than another, say coach is full, but business and first are empty, the plane can be balanced by appropriately distributing the cargo in their compartments to compensate. It is not uncommon to have to move people around in a small airliner.

cirrus