We're told that one aircraft is down but we do not have a pilot report that did it.
( ( ( ( We ( 're ( told ( that ( ( one aircraft ) ( is down ) ) ) ) ) ) but ) ( we ( ( do not ) ( have ( ( a ( pilot report ) ) ( that ( did it ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP We)) (VP (VBP 're) (VP (VBN told) (SBAR (IN that) (S (NP (CD one) (NN aircraft)) (VP (VBZ is) (ADJP (RP down)))))))) (CC but) (S (NP (PRP we)) (VP (VBP do) (RB not) (VP (VB have) (NP (NP (DT a) (NN pilot) (NN report)) (SBAR (WHNP (WDT that)) (S (VP (VBD did) (NP (PRP it))))))))) (. .)))
We hear over the phone that one aircraft is down.
( We ( ( ( ( hear over ) ( the phone ) ) ( that ( ( one aircraft ) ( is down ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBP hear) (PRT (RP over)) (NP (DT the) (NN phone)) (SBAR (IN that) (S (NP (CD one) (NN aircraft)) (VP (VBZ is) (ADJP (RP down)))))) (. .)))