It is dynamic because almost no two aircraft will be identical. Between the innumerable customization options, constant small changes in construction and inspe

It is dynamic because almost no two aircraft will be identical. Between the innumerable customization options, constant small changes in construction and inspection proceedures mean each aircraft is in some ways a unique product. This is an imporant consideration when, like here, a failure appears to have occured amongst one of the optional/customizable subsystems (emergency exit configs).