As the lead pilot explained, I reverted to the Russian threat.
( ( As ( ( the ( lead pilot ) ) explained ) ) ( , ( I ( ( reverted ( to ( the ( Russian threat ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (NP (NP (DT the) (JJ lead) (NN pilot)) (VP (VBN explained)))) (, ,) (NP (PRP I)) (VP (VBN reverted) (PP (TO to) (NP (DT the) (JJ Russian) (NN threat)))) (. .)))
The Russian threat was forgotten.
( ( The ( Russian threat ) ) ( ( was forgotten ) . ) )
(ROOT (S (NP (DT The) (JJ Russian) (NN threat)) (VP (VBD was) (VP (VBN forgotten))) (. .)))