3 5 W , ▁given ▁the ▁project ▁name ▁Constant ▁Phoenix , ▁and ▁remains ▁in ▁service ▁with ▁the ▁ 4 5 th ▁Re con na issance ▁Squadron ▁at ▁Off utt ▁Air ▁Force ▁Base , ▁Neb r aska . ▁Serial ▁no .   6 1 - 2 6 7 4 ▁was ▁converted ▁to ▁the ▁first ▁O C - 1 3 5 B ▁Open ▁Sk ies ▁observation ▁aircraft , ▁re ent ering ▁service ▁in ▁ 1 9 9 3 . ▁It ▁was ▁later ▁stored ▁in ▁ 1 9 9 7 ▁and ▁replaced ▁with ▁two ▁additional ▁aircraft . ▁ ▁In ▁ 1 9 9 8 , ▁a ▁former ▁EC - 1 3 5 C , ▁serial ▁no .   6 2 - 3 5 8 2 , ▁was ▁converted ▁into ▁a ▁W C - 1 3 5 C , ▁also ▁designated ▁Constant ▁Phoenix . ▁ ▁In ▁April ▁ 2 0 1 8 ▁it ▁was ▁announced ▁that ▁three ▁K C - 1 3 5 R ▁tank er ▁aircraft ▁would ▁be ▁converted ▁as ▁W C - 1 3 5 R ▁Constant ▁Phoenix ▁aircraft ▁to ▁replace ▁the ▁two ▁aircraft ▁operated ▁by ▁the ▁ 4 5 th ▁Re con na issance ▁Squadron . ▁The ▁first ▁aircraft ▁is ▁scheduled ▁to ▁be ▁converted ▁by ▁L 3 ▁Techn ologies ▁at ▁Green ville , ▁Texas ▁starting ▁in ▁September ▁ 2 0 1 9 . ▁ ▁Mission ▁The ▁W C - 1 3 5 B ▁and ▁W C - 1 3 5 W ▁Constant ▁Phoenix ▁atmos pher ic - collection ▁aircraft ▁support ▁national - level ▁intelligence