Sometime Pilots ask passengers to relocate to a different seat on an airplane, why is that?
Q: Flight Attendants are sometimes asked by our Pilots to relocate passengers in the aircraft cabin for weight and balance. Not surprisingly, our passengers are often perplexed by the need to do so on large aircraft. Could you please explain what this is about and why it’s required? Thanks!
A: WingmanAdventrs: The request to re-position a passenger is borne of the need to have the plane in balance. Balance refers to the location of the center of gravity (CG) along the longitudinal axis of the aircraft (nose to tail). The CG is the point about which an aircraft would balance if it were possible to suspend it from that point. There are forward and aft limits established during certification flight testing; they are the extreme CG positions at which the longitudinal stability requirements can be met. Operation outside these limits means you would be flying in an area where the aircraft’s handling has not been investigated, or is unsatisfactory.
A request to re-position a passenger is not often seen on larger jets (B737, MD80, and larger) except for some unusual and relatively rare scenarios. This is mostly seen with the regional airline type aircraft (turboprops and regional jets). The larger jets, being larger, can carry cargo in addition to passengers and their bags—that cargo can be used to ensure the CG requirements are met.