The controller tracking American 77 told us he noticed the aircraft turning to the southwest, and then saw the data disappear.
( ( ( The controller ) ( tracking ( American 77 ) ) ) ( ( ( told us ) ( ( ( ( he ( noticed ( ( the aircraft ) ( turning ( to ( the southwest ) ) ) ) ) ) , ) and ) ( then ( saw ( ( the data ) disappear ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN controller)) (VP (VBG tracking) (NP (NNP American) (CD 77)))) (VP (VBD told) (NP (PRP us)) (SBAR (S (NP (PRP he)) (VP (VBD noticed) (NP (NP (DT the) (NN aircraft)) (VP (VBG turning) (PP (TO to) (NP (DT the) (NN southwest))))))) (, ,) (CC and) (S (ADVP (RB then)) (VP (VBD saw) (SBAR (S (NP (DT the) (NNS data)) (VP (VBP disappear)))))))) (. .)))
The controller was telling the truth about the data disappearing.
( ( The controller ) ( ( was ( telling ( ( the truth ) ( about ( the ( data disappearing ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN controller)) (VP (VBD was) (VP (VBG telling) (NP (NP (DT the) (NN truth)) (PP (IN about) (NP (DT the) (NN data) (NN disappearing)))))) (. .)))