No owner or operator of an aircraft shall operate the aircraft unless all articles, baggage and cargo carried on board, except those items in use by either the flight crew or by passengers, if such use is not prohibited in the interest of the safety of the aircraft or its occupants, are placed—
(a) in a manner which prevents movement likely to cause injury or damage and does not obstruct aisles and exits; or
(b) in stowages designed to prevent movement likely to cause injury or damage.