(S (S (NP (BASENP (DT The) (JJ leading) (NN theory)) (PP (IN at) (BASENP (DT the) (NN moment)))) (VP (VBZ is) (SBAR (IN that) (S (BASENP (DT the) (NN crew)) (VP (VP (VBD received) (BASENP (JJ incorrect) (NN air) (NN speed) (NNS readings))) (PP (IN from) (NP (NP (BASENP (DT the) (NN aircraft) (POS 's)) (BASENP (NN pitot) (NNS tubes))) (COMMA ,) (NP (BASENP (NNS devices)) (SBAR (WHNP (WDT which)) (S (VP (VBP measure) (SBAR (WHADVP (WRB how) (RB fast)) (S (BASENP (DT the) (NN aircraft)) (VP (VBZ is) (VP (VBG traveling)))))))))))))))) (PERIOD .))