At 10:02, the communicators in the shelter began receiving reports from the Secret Service of an inbound aircraft-presumably hijacked-heading toward Washington.
( ( At 10:02 ) ( , ( ( ( the communicators ) ( in ( the shelter ) ) ) ( ( began ( ( receiving reports ) ( from ( ( the ( Secret Service ) ) ( of ( ( an ( inbound ( aircraft-presumably hijacked-heading ) ) ) ( toward Washington ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 10:02))) (, ,) (NP (NP (DT the) (NNS communicators)) (PP (IN in) (NP (DT the) (NN shelter)))) (VP (VBD began) (S (VP (VBG receiving) (NP (NNS reports)) (PP (IN from) (NP (NP (DT the) (NNP Secret) (NNP Service)) (PP (IN of) (NP (NP (DT an) (JJ inbound) (JJ aircraft-presumably) (NN hijacked-heading)) (PP (IN toward) (NP (NNP Washington)))))))))) (. .)))
A hijacked airplane was headed toward Washington at 10 am.
( ( A ( hijacked airplane ) ) ( ( was ( ( headed ( toward Washington ) ) ( at ( 10 am ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ hijacked) (NN airplane)) (VP (VBD was) (VP (VBN headed) (PP (IN toward) (NP (NNP Washington))) (PP (IN at) (NP (CD 10) (RB am))))) (. .)))