▁stabil izer . ▁The ▁N T SB ▁determined ▁that ▁this ▁jam med ▁the ▁elev ator ▁and ▁caused ▁the ▁loss ▁of ▁pitch ▁control , ▁but ▁could ▁not ▁determine ▁how ▁the ▁object ▁got ▁lod ged ▁in ▁between ▁the ▁two ▁surfaces , ▁though ▁one ▁scenario ▁stated ▁that ▁the ▁object ▁was ▁blow n ▁in ▁by ▁w ake ▁tur bul ence ▁from ▁the ▁aircraft ▁that ▁took ▁off ▁before ▁Fl ight ▁ 8 6 3 . ▁ ▁The ▁N T SB ▁published ▁its ▁final ▁report ▁on ▁August ▁ 1 8 , ▁ 1 9 7 1 , ▁with ▁the ▁" prob able ▁cause " ▁section ▁stating : ▁The ▁Board ▁determ ines ▁that ▁the ▁probable ▁cause ▁of ▁this ▁accident ▁was ▁a ▁loss ▁of ▁pitch ▁control ▁caused ▁by ▁the ▁ent rap ment ▁of ▁a ▁point , ▁as ph alt - cover ed ▁object ▁between ▁the ▁leading ▁edge ▁of ▁the ▁right ▁elev ator ▁and ▁the ▁right ▁horizontal ▁sp ar ▁web ▁access ▁door ▁in ▁the ▁a ft ▁part ▁of ▁the ▁stabil izer . ▁The ▁restriction ▁to ▁elev ator ▁movement , ▁caused ▁by ▁a ▁highly ▁unusual ▁and ▁unknown ▁condition , ▁was ▁not ▁detected ▁by ▁the ▁crew ▁in ▁time ▁to ▁reject ▁the ▁take off ▁successfully . ▁However , ▁an ▁apparent ▁lack ▁of ▁crew ▁respons iveness ▁to ▁a ▁highly ▁unusual ▁emer gency ▁situation , ▁couple d ▁with ▁the ▁captain ' s ▁failure ▁to ▁monitor ▁ade qu ately ▁the ▁take off , ▁contributed ▁to ▁the ▁failure ▁to ▁reject ▁the ▁take off . ▁ ▁After math ▁ ▁After ▁the ▁accident , ▁the ▁Federal ▁A viation ▁Administration ▁( FA