The call lasted about two minutes, after which Policastro and a colleague tried unsuccessfully to contact the flight.
( ( The call ) ( ( lasted ( about ( ( ( two minutes ) , ) ( ( after which ) ( ( ( Policastro and ) ( a colleague ) ) ( ( tried unsuccessfully ) ( to ( contact ( the flight ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN call)) (VP (VBD lasted) (PP (IN about) (NP (NP (CD two) (NNS minutes)) (, ,) (SBAR (WHPP (IN after) (WHNP (WDT which))) (S (NP (NP (NNP Policastro)) (CC and) (NP (DT a) (NN colleague))) (VP (VBD tried) (ADVP (RB unsuccessfully)) (S (VP (TO to) (VP (VB contact) (NP (DT the) (NN flight))))))))))) (. .)))
Policastro and a colleague were not able to call the flight. 
( ( ( Policastro and ) ( a colleague ) ) ( ( ( were not ) ( able ( to ( call ( the flight ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Policastro)) (CC and) (NP (DT a) (NN colleague))) (VP (VBD were) (RB not) (ADJP (JJ able) (S (VP (TO to) (VP (VB call) (NP (DT the) (NN flight))))))) (. .)))