By 8:33, it had reached its assigned cruising altitude of 31,000 feet.
( ( By 8:33 ) ( , ( it ( ( had ( reached ( ( its ( assigned ( cruising altitude ) ) ) ( of ( 31,000 feet ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN By) (NP (CD 8:33))) (, ,) (NP (PRP it)) (VP (VBD had) (VP (VBN reached) (NP (NP (PRP$ its) (VBN assigned) (NN cruising) (NN altitude)) (PP (IN of) (NP (CD 31,000) (NNS feet)))))) (. .)))
By 8:33 is was on its delegated cruising altitude of about 30,000 feet.
( ( By 8:33 ) ( ( ( is ( was ( on ( its ( delegated cruising ) ) ) ) ) ( altitude ( of ( ( about 30,000 ) feet ) ) ) ) . ) )
(ROOT (S (PP (IN By) (NP (CD 8:33))) (VP (VBZ is) (VP (VBD was) (PP (IN on) (NP (PRP$ its) (JJ delegated) (NN cruising))))) (NP (NP (NN altitude)) (PP (IN of) (NP (QP (RB about) (CD 30,000)) (NNS feet)))) (. .)))