It is not clear how the shootdown order was communicated within NORAD.
( It ( ( ( ( is not ) clear ) ( how ( ( the ( shootdown order ) ) ( was ( communicated ( within NORAD ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (RB not) (ADJP (JJ clear)) (SBAR (WHADVP (WRB how)) (S (NP (DT the) (NN shootdown) (NN order)) (VP (VBD was) (VP (VBN communicated) (PP (IN within) (NP (NNP NORAD)))))))) (. .)))
It is not clear how or why the shootdown order was communicated. 
( It ( ( ( ( is not ) clear ) ( ( ( how or ) why ) ( ( the ( shootdown order ) ) ( was communicated ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (RB not) (ADJP (JJ clear)) (SBAR (WHADVP (WRB how) (CC or) (WRB why)) (S (NP (DT the) (NN shootdown) (NN order)) (VP (VBD was) (VP (VBN communicated)))))) (. .)))