▁Be ech craft ▁to ▁build ▁pro tot ypes ▁for ▁advanced ▁aircraft , ▁for ▁a ▁ 6 2 % ▁scale ▁proof - of - con cept ▁demonstr ator ▁for ▁the ▁concept , ▁called ▁the ▁Advanced ▁Technology ▁T act ical ▁Transport ▁( short ened ▁to ▁AT TT ▁or ▁AT 3 ). ▁ ▁The ▁AT TT ▁had ▁high - as pect ▁ratio ▁tan dem ▁wings , ▁which ▁were ▁joined ▁by ▁long ▁nac elles ▁which ▁carried ▁the ▁aircraft ' s ▁engines , ▁tra ctor ▁configuration ▁tur b opro ps , ▁large ▁fuel ▁t anks ▁and ▁the ▁as ▁well ▁as ▁the ▁main ▁under car riage ▁units ▁for ▁the ▁aircraft ' s ▁ret ract able ▁tr icy cle ▁landing ▁g ear . ▁As ▁first ▁built , ▁it ▁had ▁a ▁conventional , ▁cru c iform ▁tail . ▁A ▁novel ▁arrangement ▁of ▁eight ▁fast ▁acting ▁f ow ler ▁f laps ▁was ▁fitted , ▁in board ▁and ▁out board ▁of ▁the ▁engines ▁on ▁each ▁of ▁the ▁wings . ▁These ▁would ▁be ▁extended ▁rear wards ▁in ▁a ▁low - drag ▁configuration ▁prior ▁to ▁comm encing ▁the ▁take - off ▁run ▁then ▁quickly ▁lower ed ▁to ▁increase ▁lift ▁at ▁the ▁point ▁of ▁take - off . ▁The ▁aircraft ▁was ▁of ▁composite ▁construction , ▁mainly ▁glass f ib re ▁and ▁carbon ▁fib re . ▁It ▁was ▁power ed ▁by ▁two ▁Pr att ▁& ▁Whit ney ▁Canada ▁P T 6 A - 1 3 5 ▁tur b opro ps . ▁▁ ▁The ▁AT TT ▁demonstr ator ▁made ▁its ▁ma iden ▁flight ▁on ▁December ▁ 2 9