Sixteen seconds after that transmission, ATC instructed the aircraft's pilots to climb to 35,000 feet.
( ( ( Sixteen seconds ) ( after ( that transmission ) ) ) ( , ( ATC ( ( instructed ( ( the ( aircraft 's ) ) ( pilots ( to ( climb ( to ( 35,000 feet ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (NP (NN Sixteen) (NNS seconds)) (IN after) (NP (DT that) (NN transmission))) (, ,) (NP (NNP ATC)) (VP (VBD instructed) (NP (NP (DT the) (NN aircraft) (POS 's)) (NNS pilots) (S (VP (TO to) (VP (VB climb) (PP (TO to) (NP (CD 35,000) (NNS feet)))))))) (. .)))
The aircraft's pilots immediately began their assent upwards.
( ( ( The ( aircraft 's ) ) pilots ) ( immediately ( ( began ( their ( assent upwards ) ) ) . ) ) )
(ROOT (S (NP (NP (DT The) (NN aircraft) (POS 's)) (NNS pilots)) (ADVP (RB immediately)) (VP (VBD began) (NP (PRP$ their) (NN assent) (NNS upwards))) (. .)))