▁of ▁the ▁enorm ous , ▁flat ▁surface ▁of ▁Rog ers ▁D ry ▁Lake ▁about ▁six ▁miles ▁away ▁from ▁the ▁training ▁base ▁at ▁M uro c . ▁Gr ound ▁tests ▁began ▁five ▁days ▁after ▁the ▁first ▁XP - 5 9 ▁arrived ▁on ▁ 2 1 ▁September ▁ 1 9 4 2 . ▁First ▁flight ▁took ▁place ▁on ▁ 3 0 ▁September ▁when ▁the ▁XP - 5 9 ▁rose ▁to ▁ ▁alt itude ▁for ▁ ▁during ▁tax i ▁testing . ▁ ▁However , ▁the ▁first ▁official ▁flight ▁was ▁ 1 ▁October ▁ 1 9 4 2 ▁with ▁N AC A , ▁Navy ▁Bureau ▁of ▁Aer onaut ics , ▁Royal ▁Air ▁Force , ▁Army , ▁Bell ▁and ▁General ▁Electric ▁personnel ▁on ▁hand . ▁ ▁As ▁with ▁virt ually ▁all ▁of ▁the ▁test ▁programs ▁conducted ▁during ▁the ▁war ▁years , ▁most ▁of ▁the ▁actual ▁flight ▁test ▁work ▁on ▁the ▁P - 5 9 ▁was ▁conducted ▁by ▁the ▁contract or . ▁Although ▁Army ▁Air ▁Forces ▁( A AF ) ▁pil ots ▁fle w ▁the ▁aircraft ▁from ▁time ▁to ▁time , ▁and ▁flight ▁test ▁engine ers ▁from ▁Wright ▁Field ▁review ed ▁the ▁data , ▁the ▁formal ▁pre lim inary ▁military ▁test ▁and ▁evaluation ▁program ▁did ▁not ▁commence ▁until ▁the ▁Fall ▁of ▁ 1 9 4 3 , ▁a ▁year ▁after ▁the ▁first ▁flight . ▁Design ed ▁to ▁validate ▁the ▁contract or ' s ▁reports , ▁this ▁pre lim inary ▁evaluation ▁consisted ▁of ▁a ▁very ▁limited ▁number ▁of ▁fl ights ▁and ▁was ▁essentially ▁completed ▁within ▁a ▁month . ▁F ormal