He tried the radios, first calling the aircraft directly, then the airline.
( He ( ( ( ( tried ( the radios ) ) , ) ( first ( calling ( ( ( ( the aircraft ) directly ) , ) ( then ( the airline ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD tried) (NP (DT the) (NNS radios)) (, ,) (S (ADVP (RB first)) (VP (VBG calling) (S (S (NP (DT the) (NN aircraft)) (ADVP (RB directly))) (, ,) (S (ADVP (RB then)) (NP (DT the) (NN airline))))))) (. .)))
The airline didn't know where he was.
( ( The airline ) ( ( ( did n't ) ( know ( where ( he was ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN airline)) (VP (VBD did) (RB n't) (VP (VB know) (SBAR (WHADVP (WRB where)) (S (NP (PRP he)) (VP (VBD was)))))) (. .)))