At 8:48, while the controller was still trying to locate American 11, a New York Center manager provided the following report on a Command Center teleconference about American 11:
( ( At 8:48 ) ( , ( ( while ( ( the controller ) ( ( was still ) ( trying ( to ( locate ( American 11 ) ) ) ) ) ) ) ( , ( ( a ( New ( York ( Center manager ) ) ) ) ( ( ( ( provided ( the ( following report ) ) ) ( on ( a ( Command ( Center teleconference ) ) ) ) ) ( about ( American 11 ) ) ) : ) ) ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 8:48))) (, ,) (SBAR (IN while) (S (NP (DT the) (NN controller)) (VP (VBD was) (ADVP (RB still)) (VP (VBG trying) (S (VP (TO to) (VP (VB locate) (NP (NNP American) (CD 11))))))))) (, ,) (NP (DT a) (NNP New) (NNP York) (NNP Center) (NN manager)) (VP (VBD provided) (NP (DT the) (JJ following) (NN report)) (PP (IN on) (NP (DT a) (NNP Command) (NNP Center) (NN teleconference))) (PP (IN about) (NP (NNP American) (CD 11)))) (: :)))
A manager at the  New York Center gave the report that follows while the controller was still unable to find American 11.
( ( ( A manager ) ( at ( the ( New ( York Center ) ) ) ) ) ( ( gave ( ( the report ) ( that ( follows ( while ( ( the controller ) ( ( was still ) ( unable ( to ( find ( American 11 ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN manager)) (PP (IN at) (NP (DT the) (NNP New) (NNP York) (NNP Center)))) (VP (VBD gave) (NP (NP (DT the) (NN report)) (SBAR (WHNP (WDT that)) (S (VP (VBZ follows) (SBAR (IN while) (S (NP (DT the) (NN controller)) (VP (VBD was) (ADVP (RB still)) (ADJP (JJ unable) (S (VP (TO to) (VP (VB find) (NP (NNP American) (CD 11)))))))))))))) (. .)))