In the succeeding minutes, controllers were attempting to ascertain the altitude of the southbound flight.
( ( In ( the ( succeeding minutes ) ) ) ( , ( controllers ( ( were ( attempting ( to ( ascertain ( ( the altitude ) ( of ( the ( southbound flight ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (DT the) (VBG succeeding) (NNS minutes))) (, ,) (NP (NNS controllers)) (VP (VBD were) (VP (VBG attempting) (S (VP (TO to) (VP (VB ascertain) (NP (NP (DT the) (NN altitude)) (PP (IN of) (NP (DT the) (JJ southbound) (NN flight))))))))) (. .)))
Controllers had the altitude of the plane on their screen.
( Controllers ( ( had ( ( the altitude ) ( of ( ( the plane ) ( on ( their screen ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Controllers)) (VP (VBD had) (NP (NP (DT the) (NN altitude)) (PP (IN of) (NP (NP (DT the) (NN plane)) (PP (IN on) (NP (PRP$ their) (NN screen))))))) (. .)))