At 8:28, Boston Center called the Command Center in Herndon to advise that it believed American 11 had been hijacked and was heading toward New York Center's airspace.
( ( At 8:28 ) ( , ( ( Boston Center ) ( ( ( ( ( called ( ( the ( Command Center ) ) ( in Herndon ) ) ) ( to ( advise ( that ( it ( believed ( ( American 11 ) ( had ( been hijacked ) ) ) ) ) ) ) ) ) and ) ( was ( heading ( toward ( ( New ( York ( Center 's ) ) ) airspace ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 8:28))) (, ,) (NP (NNP Boston) (NNP Center)) (VP (VP (VBD called) (NP (NP (DT the) (NNP Command) (NNP Center)) (PP (IN in) (NP (NNP Herndon)))) (S (VP (TO to) (VP (VB advise) (SBAR (IN that) (S (NP (PRP it)) (VP (VBD believed) (SBAR (S (NP (NNP American) (CD 11)) (VP (VBD had) (VP (VBN been) (VP (VBN hijacked))))))))))))) (CC and) (VP (VBD was) (VP (VBG heading) (PP (IN toward) (NP (NP (NNP New) (NNP York) (NNP Center) (POS 's)) (NN airspace)))))) (. .)))
Houston Center called the Command center in Herndon.
( ( Houston Center ) ( ( ( called ( the ( Command center ) ) ) ( in Herndon ) ) . ) )
(ROOT (S (NP (NNP Houston) (NNP Center)) (VP (VBD called) (NP (DT the) (NNP Command) (NN center)) (PP (IN in) (NP (NNP Herndon)))) (. .)))