Originally Posted by LarryJ

The 757 issue, from what I understand, has to do with the load limit of the floor in certain sections of the airplane. When the average passenger weights transition to winter weights on November 1st, you can no longer have all seats filled and still comply with that limitation. Depending on the aircraft configuration, either three or six seats, all middle seats, are blocked and unusable on the affected aircraft during the period that winter weights are used. Each blocked seat is marked as unusable and can not be occupied for any reason.