(S (S (S (NP (NP (BASENP (DT The) (NNS remains)) (PP (IN of) (BASENP (DT the) (NN plane)))) (PRN (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBD were) (VP (VBN concentrated) (PP (IN in) (NP (DT a) (NP (NP (NP (BASENP (NN 600) (NNS metres)) (PP (IN by) (BASENP (NN 200) (NNS metres)))) (PRN (LRB -LRB-) (NP (BASENP (NN 1,968) (NNS feet)) (PP (IN by) (BASENP (NN 656) (NNS feet)))) (RRB -RRB-))) (NN area)))))))) (COMMA ,))) (VP (VBP appear) (S (VP (TO to) (VP (VB be) (ADJP (RB relatively) (JJ intact))))))) (SBAR (WHNP (WDT which)) (S (VP (VBZ leads) (S (BASENP (NNS investigators)) (VP (TO to) (VP (VB believe) (SBAR (IN that) (S (BASENP (DT the) (NN plane)) (VP (VP (VP (VBD hit) (BASENP (DT the) (NN water))) (ADVP (RB intact))) (CC and) (VP (VP (VBD did) (RB not)) (VP (VB explode) (ADVP (RB mid-air)))))))))))))) (PERIOD .))