( ( When ( ( these engines ) ( are ( operated ( at ( high altitudes ) ) ) ) ) ) ( , ( ( the ( A. ( low ( pressure rotor ) ) ) ) ( ( will ( ( increase ( in speed ) ) ( as ( ( the ( compressor load ) ) ( decreases ( in ( the ( lower ( density air ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT these) (NNS engines)) (VP (VBP are) (VP (VBN operated) (PP (IN at) (NP (JJ high) (NNS altitudes))))))) (, ,) (NP (DT the) (NNP A.) (JJ low) (NN pressure) (NN rotor)) (VP (MD will) (VP (VB increase) (PP (IN in) (NP (NN speed))) (SBAR (IN as) (S (NP (DT the) (NN compressor) (NN load)) (VP (VBZ decreases) (PP (IN in) (NP (DT the) (JJR lower) (NN density) (NN air)))))))) (. .)))
When these engines are operated at high altitudes, the A. low pressure rotor will increase in speed as the compressor load decreases in the lower density air.
(ROOT (S (SBAR (IN As) (S (NP (DT the) (NN altitude)) (VP (VBZ decreases)))) (, ,) (NP (NP (DT the) (NN density)) (PP (IN of) (NP (NN air)))) (VP (VBZ decreases)) (. .)))