Within seconds, the Command Center received a visual report from another aircraft, and informed headquarters that the aircraft was 20 miles northwest of Johnstown.
( ( Within seconds ) ( , ( ( the ( Command Center ) ) ( ( ( ( ( ( received ( a ( visual report ) ) ) ( from ( another aircraft ) ) ) , ) and ) ( ( informed headquarters ) ( that ( ( the aircraft ) ( ( was ( ( 20 miles ) northwest ) ) ( of Johnstown ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN Within) (NP (NNS seconds))) (, ,) (NP (DT the) (NNP Command) (NNP Center)) (VP (VP (VBD received) (NP (DT a) (JJ visual) (NN report)) (PP (IN from) (NP (DT another) (NN aircraft)))) (, ,) (CC and) (VP (VBD informed) (NP (NN headquarters)) (SBAR (IN that) (S (NP (DT the) (NN aircraft)) (VP (VBD was) (ADVP (NP (CD 20) (NNS miles)) (RB northwest)) (PP (IN of) (NP (NNP Johnstown)))))))) (. .)))
The Command Center never got a visual report about the plane, so they relied on radar.
( ( ( ( ( ( The ( Command Center ) ) ( never ( ( got ( a ( visual report ) ) ) ( about ( the plane ) ) ) ) ) , ) so ) ( they ( relied ( on radar ) ) ) ) . )
(ROOT (S (S (NP (DT The) (NNP Command) (NNP Center)) (ADVP (RB never)) (VP (VBD got) (NP (DT a) (JJ visual) (NN report)) (PP (IN about) (NP (DT the) (NN plane))))) (, ,) (IN so) (S (NP (PRP they)) (VP (VBN relied) (PP (IN on) (NP (NN radar))))) (. .)))