Jarrah, like Atta earlier, may have inadvertently broadcast the message because he did not know how to operate the radio and the intercom.
( Jarrah ( , ( ( like ( Atta earlier ) ) ( , ( ( may ( have ( inadvertently ( ( broadcast ( the message ) ) ( because ( he ( ( did not ) ( know ( how ( to ( operate ( ( ( the radio ) and ) ( the intercom ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (NP (NNP Jarrah)) (, ,) (PP (IN like) (ADVP (NP (NNP Atta)) (RBR earlier))) (, ,) (VP (MD may) (VP (VB have) (VP (ADVP (RB inadvertently)) (VBN broadcast) (NP (DT the) (NN message)) (SBAR (IN because) (S (NP (PRP he)) (VP (VBD did) (RB not) (VP (VB know) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB operate) (NP (NP (DT the) (NN radio)) (CC and) (NP (DT the) (NN intercom)))))))))))))) (. .)))
Jarrah was intimately familiar with, and adept at using the intercom and radio.
( Jarrah ( ( ( ( was intimately ) ( ( ( ( familiar with ) , ) and ) adept ) ) ( at ( using ( the ( ( intercom and ) radio ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Jarrah)) (VP (VBD was) (ADVP (RB intimately)) (ADJP (ADJP (JJ familiar) (PP (IN with))) (, ,) (CC and) (ADJP (JJ adept))) (PP (IN at) (S (VP (VBG using) (NP (DT the) (NN intercom) (CC and) (NN radio)))))) (. .)))