Freight or cargo is secured in Unit Load Devices (ULDs), such as containers and pallets or restrained with nets as bulk cargo, to stop it shifting in flight, which may result in unplanned Centre of Gravity (CG) movement and stay within the aircraft’s CG limits.
Container ULDs have a specific shape and size depending on the dimensions of the fuselage. When the freight dimensions are unsuitable for container ULDs, pallets with load spreading bars are used and the freight is secured with a cargo net and covered with a fire containment blanket if required.
Shifting loads would affect the CG position, quite possibly causing an accident or damage to the airframe from inside.
Your Notes (not visible to others)
This question has appeared on the real examination, you can find the related countries below.