Between 8:25 and 8:32, in accordance with the FAA protocol, Boston Center managers started notifying their chain of command that American 11 had been hijacked.
( ( Between ( ( 8:25 and ) 8:32 ) ) ( , ( ( in ( accordance ( with ( the ( FAA protocol ) ) ) ) ) ( , ( ( Boston ( Center managers ) ) ( ( ( started ( notifying ( ( their chain ) ( of command ) ) ) ) ( that ( ( American 11 ) ( had ( been hijacked ) ) ) ) ) . ) ) ) ) ) )
(ROOT (S (PP (IN Between) (NP (CD 8:25) (CC and) (CD 8:32))) (, ,) (PP (IN in) (NP (NP (NN accordance)) (PP (IN with) (NP (DT the) (NNP FAA) (NN protocol))))) (, ,) (NP (NNP Boston) (NNP Center) (NNS managers)) (VP (VBD started) (S (VP (VBG notifying) (NP (NP (PRP$ their) (NN chain)) (PP (IN of) (NP (NN command)))))) (SBAR (IN that) (S (NP (NNP American) (CD 11)) (VP (VBD had) (VP (VBN been) (VP (VBN hijacked))))))) (. .)))
it was not until 9:00 that Boston Center messengers realized that American 11 had been hijacked.
( it ( ( ( ( was not ) ( until 9:00 ) ) ( that ( ( Boston ( Center messengers ) ) ( realized ( that ( ( American 11 ) ( had ( been hijacked ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP it)) (VP (VBD was) (RB not) (PP (IN until) (NP (CD 9:00))) (SBAR (IN that) (S (NP (NNP Boston) (NNP Center) (NNS messengers)) (VP (VBD realized) (SBAR (IN that) (S (NP (NNP American) (CD 11)) (VP (VBD had) (VP (VBN been) (VP (VBN hijacked)))))))))) (. .)))