▁a ▁common ▁fus el age , ▁as ▁a ▁single ▁k it , ▁with ▁the ▁choice ▁of ▁wings , ▁but ▁it ▁seems ▁none ▁was ▁actually ▁produced . ▁ ▁Oper ational ▁history ▁The ▁sole ▁B KB - 1 A ▁was ▁destroyed ▁on ▁ 6 ▁November ▁ 1 9 7 1 ▁near ▁Ar ling ton , ▁Washington , ▁when ▁a ▁pilot ▁conducted ▁una ut hor ized ▁aer ob at ics ▁in ▁the ▁aircraft , ▁subject ing ▁it ▁to ▁an ▁estimated ▁negative ▁ 3 0 g ▁during ▁a ▁high - speed ▁invert ed ▁descent . ▁The ▁ 3 1 - year - old ▁commercial ▁pilot , ▁who ▁had ▁a ▁total ▁of ▁ 3 0 0 0 ▁flying ▁hours ▁and ▁five ▁hours ▁on ▁type , ▁was ▁we aring ▁a ▁par ach ute , ▁but ▁did ▁not ▁b ail ▁out ▁and ▁was ▁killed ▁in ▁the ▁accident . ▁The ▁National ▁Transport ation ▁Saf ety ▁Board ▁c ited ▁as ▁cause ▁factors ▁that ▁the ▁pilot ▁mis jud ged ▁the ▁aircraft ' s ▁speed ▁and ▁over str essed ▁the ▁air frame ▁to ▁failure . ▁ ▁Vari ants ▁B KB - 1 ▁Early ▁configuration ▁of ▁the ▁aircraft ▁B KB - 1 A ▁Later ▁configuration ▁of ▁the ▁same ▁aircraft ▁with ▁modifications ▁for ▁par ach ute ▁flight ▁above ▁the ▁st alling ▁angle ▁and ▁also ▁aer ob at ics . ▁ ▁Spec ifications ▁( B KB - 1 ) ▁ ▁See ▁also ▁ ▁Notes ▁ ▁References ▁ ▁Category : 1 9 5 0 s ▁Canadian ▁sail plan es ▁Category : Home built ▁aircraft ▁Category : T a