▁mar itime ▁pat rol ▁aircraft ▁until ▁sufficient ▁numbers ▁of ▁the ▁Av ro ▁Sh ack leton ▁could ▁enter ▁service . ▁The ▁Ne pt unes ▁were ▁used ▁from ▁between ▁ 1 9 5 2 ▁and ▁March ▁ 1 9 5 7 , ▁being ▁used ▁for ▁Air bor ne ▁Early ▁Warning ▁experiments ▁as ▁well ▁as ▁for ▁mar itime ▁pat rol . ▁ ▁In ▁Australia , ▁the ▁Netherlands , ▁and ▁the ▁US ▁Navy , ▁its ▁tasks ▁were ▁taken ▁over ▁by ▁the ▁larger ▁and ▁more ▁capable ▁P - 3 ▁Or ion , ▁and ▁by ▁the ▁ 1 9 7 0 s , ▁it ▁was ▁in ▁use ▁only ▁by ▁pat rol ▁squad rons ▁in ▁the ▁US ▁Naval ▁Reserve ▁and ▁the ▁Dutch ▁Navy . ▁The ▁US ▁Naval ▁Reserve ▁retired ▁its ▁last ▁Ne pt unes ▁in ▁ 1 9 7 8 , ▁those ▁aircraft ▁also ▁having ▁been ▁replaced ▁by ▁the ▁P - 3 ▁Or ion . ▁By ▁the ▁ 1 9 8 0 s , ▁the ▁Ne pt une ▁had ▁fallen ▁out ▁of ▁military ▁use ▁in ▁most ▁purch asing ▁nations , ▁replaced ▁by ▁newer ▁aircraft . ▁ ▁In ▁Japan , ▁the ▁Ne pt une ▁was ▁license - built ▁from ▁ 1 9 6 6 ▁by ▁K aw as aki ▁as ▁the ▁P - 2 J , ▁with ▁the ▁p ist on ▁engines ▁replaced ▁by ▁I HI - built ▁T 6 4 ▁tur b opro ps . ▁K aw as aki ▁continued ▁their ▁manufact ure ▁much ▁later ▁than ▁Lock he ed ▁did ; ▁the ▁P - 2 J ▁remained ▁in ▁service ▁until