), ▁modified ▁arm ament , ▁and ▁the ▁new ▁mirror ▁landing ▁system . ▁Ark ▁Royal ▁was ▁the ▁first ▁ship ▁to ▁be ▁constructed ▁with ▁an ▁ang led ▁flight ▁deck ▁and ▁steam ▁cat ap ult s , ▁as ▁opposed ▁to ▁having ▁them ▁added ▁after ▁launch ing . ▁These ▁innov ations ▁allowed ▁aircraft ▁to ▁land ▁and ▁take ▁off ▁from ▁the ▁car rier ▁at ▁the ▁same ▁time . ▁Her ▁flight ▁deck ▁as ▁built ▁was ▁. ▁ ▁A ▁further ▁four ▁years ▁passed ▁before ▁she ▁comm enced ▁her ▁sea ▁tri als . ▁ ▁About ▁a ▁year ▁after ▁commission ing , ▁her ▁forward ▁port ▁ ▁guns ▁were ▁removed ▁to ▁improve ▁aircraft ▁operations ▁over ▁the ▁ang led ▁deck . ▁ ▁Four ▁years ▁later , ▁the ▁port ▁deck - edge ▁lift ▁and ▁the ▁forward ▁star board ▁ 4 . 5 - inch ▁guns ▁were ▁also ▁removed . ▁After ▁the ▁ 1 9 6 4 ▁ref it ▁only ▁one ▁tw in ▁ 4 . 5 - inch ▁gun ▁mount ▁remained ▁a ft ▁on ▁port ▁and ▁star board ▁side . ▁From ▁ 1 9 6 7 ▁to ▁February ▁ 1 9 7 0 , ▁she ▁under w ent ▁a ▁ref it ▁which ▁was ▁a ▁major ▁re build ▁to ▁her ▁structure , ▁but ▁only ▁an ▁aust ere ▁update ▁to ▁her ▁electronic ▁equipment , ▁and ▁was ▁conf ined ▁to ▁changes ▁needed ▁to ▁operate ▁the ▁R N ' s ▁version ▁of ▁the ▁Ph antom . ▁Prior ▁to , ▁and ▁during ▁the ▁ref it , ▁concerns ▁over ▁costs , ▁the ▁age ▁of ▁the ▁h ull ▁and ▁changing ▁political ▁opinions