Asked to define “Quality”, most engineers will have been taught to reply “fit for purpose”, as measured against a defined requirement and specification. It means both generally (in simple terms an aircraft must be able to fly) and specifically (it must be able to carry out its stated roles) – safely and underpinned by correct application of all the safety and airworthiness process, procedures and regulations described at length in this thread.
Browne and Ainsworth (and before him, Ingram), and their respective advisors, are at loggerheads over this (having given contrasting answers to the same questions regarding the above). How they must be hoping the QC’s review recommends cancellation of MRA4.