At 8:23, the dispatcher tried unsuccessfully to contact the aircraft.
( ( At 8:23 ) ( , ( ( the dispatcher ) ( ( ( tried unsuccessfully ) ( to ( contact ( the aircraft ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (CD 8:23))) (, ,) (NP (DT the) (NN dispatcher)) (VP (VBD tried) (ADVP (RB unsuccessfully)) (S (VP (TO to) (VP (VB contact) (NP (DT the) (NN aircraft)))))) (. .)))
The dispatcher reached was able to contact the aircraft at 8:23.
( ( ( The dispatcher ) reached ) ( ( was ( able ( to ( ( contact ( the aircraft ) ) ( at 8:23 ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN dispatcher)) (VP (VBN reached))) (VP (VBD was) (ADJP (JJ able) (S (VP (TO to) (VP (VB contact) (NP (DT the) (NN aircraft)) (PP (IN at) (NP (CD 8:23)))))))) (. .)))