▁ ▁In ▁log istics , ▁this ▁is ▁known ▁as ▁Dim in ishing ▁Man ufact uring ▁S ources ▁( D MS ). ▁▁ ▁This ▁is ▁often ▁the ▁case ▁in ▁the ▁military , ▁and ▁ships ▁and ▁aircraft , ▁as ▁well ▁as ▁other ▁expensive ▁equipment ▁that ▁is ▁produced ▁in ▁limited ▁quantities . ▁ ▁Such ▁was ▁the ▁case ▁with ▁the ▁aircraft ▁car rier ▁USS ▁K itt y ▁Haw k , ▁the ▁sole ▁surv iv or ▁of ▁a ▁class ▁of ▁three ▁ships ▁built ▁during ▁the ▁early - 1 9 6 0 s . ▁The ▁ship ▁herself ▁is ▁over ▁forty ▁years ▁old , ▁and ▁having ▁manufact ur ers ▁build ▁individual ▁custom ▁replacement ▁parts ▁would ▁be ▁highly ▁imp ract ical , ▁and ▁thus ▁de comm ission ed ▁ships , ▁such ▁as ▁the ▁USS ▁Independ ence , ▁have ▁been ▁util ized ▁for ▁the ▁necessary ▁parts ▁to ▁keep ▁the ▁K itt y ▁Haw k ▁in ▁operation . ▁ ▁Another ▁example ▁is ▁the ▁Union ▁Pacific ' s ▁ 4 - 8 - 4 ▁locomot ive ▁ 8 3 8 ▁is ▁used ▁as ▁a ▁spare ▁parts ▁source ▁for ▁ 8 4 4 ▁since ▁the ▁type ▁has ▁been ▁out ▁of ▁production ▁for ▁dec ades ▁and ▁its ▁builder ▁no ▁longer ▁exists . ▁ ▁One ▁strategy ▁used ▁to ▁combat ▁D MS ▁is ▁to ▁buy ▁additional ▁invent ory ▁during ▁the ▁production ▁run ▁of ▁a ▁system ▁or ▁part , ▁in ▁quantities ▁sufficient ▁to ▁cover ▁the ▁expected ▁number ▁of ▁fail ures . ▁ ▁This ▁strategy ▁is ▁known ▁as ▁a ▁lifetime ▁buy . ▁ ▁See ▁also ▁▁ ▁A ircraft ▁b oney