1 7 : 3 0 ▁hours ▁on ▁ 3 1 ▁July ▁ 1 9 7 9 . ▁The ▁Air ▁Acc idents ▁Investig ation ▁Branch ▁( AA IB ) ▁comm enced ▁their ▁investigation ▁the ▁following ▁morning . ▁ ▁The ▁entire ▁w reck age ▁was ▁salv aged ▁and ▁removed ▁for ▁a ▁detailed ▁exam ination , ▁which ▁needed ▁to ▁take ▁into ▁account ▁the ▁additional ▁damage ▁that ▁had ▁resulted ▁from ▁the ▁action ▁of ▁the ▁sea ▁and ▁the ▁salv age ▁operation . ▁Both ▁engines ▁were ▁stri pped ▁down ▁and ▁exam ined , ▁but ▁no ▁evidence ▁of ▁pre - imp act ▁failure ▁was ▁found . ▁The ▁prop eller ▁control ▁units ▁were ▁tested ▁and ▁were ▁discovered ▁to ▁perform ▁within ▁specification . ▁No ▁evidence ▁of ▁fire , ▁smoke , ▁or ▁over he ating ▁was ▁found . ▁ ▁Although ▁the ▁comp ass ▁selector ▁was ▁discovered ▁to ▁have ▁been ▁switched ▁to ▁the ▁co - p il ot ' s ▁instrument , ▁it ▁was ▁not ▁established ▁which ▁pilot ▁handled ▁the ▁take off ▁( company ▁reg ulations ▁stated ▁that ▁the ▁commander ▁should ▁perform ▁this ▁if ▁the ▁co - p il ot ▁was ▁in ex per ien ced ). ▁It ▁was ▁however ▁considered ▁possible ▁that ▁it ▁had ▁been ▁moved ▁during ▁ev acu ation ▁or ▁salv age . ▁ ▁C ause ▁The ▁AA IB ▁investigation ▁concluded ▁that ▁the ▁accident ▁was ▁caused ▁by ▁the ▁locked ▁condition ▁of ▁the ▁aircraft ' s ▁elev ators ▁which ▁prevent ed ▁the ▁aircraft ▁rot ating ▁into ▁a ▁flying ▁attitude . ▁It ▁was ▁thought ▁likely ▁that ▁the ▁elev ator ▁g ust ▁lock ▁became ▁re