(S (S (ADVP (RB However)) (COMMA ,) (S (BASENP (NNP Flight) (NNP Safety)) (VP (VBP claim) (SBAR (IN that) (S (SBAR (WHADVP (WRB when)) (S (VP (VBN approached)))) (COMMA ,) (S (BASENP (DT the) (NNP ATSB)) (VP (VBD denied) (S (VP (VBG knowing) (PP (IN about) (BASENP (PRP it)))))))))))) (PERIOD .))