On a recent flight from Washington, DC to Toronto, the pilot gave very specific directions to rebalance the plane (a Dash-8 IIRC), something like "someone needs to move to seat 11E."
How did he know that putting someone in seat 11E would balance the plane properly? Does the plane weigh itself or is there a computer model somewhere that tells him what to do? Or would an experienced pilot be able to look at the seat chart and know what to do?