A gas turbine engine (10;10';110;110';210;210';410;410';510;510';610;610'), comprising: a low pressure compressor section in fluid communication with an air inlet and drivingly engaged by a low pressure turbine section , the low pressure compressor section having low pressure compressor stages spaced apart along an axis of rotation of the low pressure compressor section , and the low pressure compressor section having a fluid conduit extending between the air inlet and the low pressure compression stages , the fluid conduit (27;227) having at least one flow diverter displaceable between a first position and a second position to modulate air flow through the low pressure compressor stages , the fluid conduit (27;227) including a first fluid conduit segment (27A, 27B;227A, 227B) extending between the air inlet and one of the low pressure compression stages , and a second fluid conduit segment (27A, 27B;227A, 227B) extending between the air inlet and another one of the low pressure compression stages , the first and second fluid conduit segments (27A, 27B;227A, 227B) meeting at a fluid conduit junction (27C;227C), the at least one flow diverter positioned about the fluid conduit junction (27C;227C) and displaceable between the first position to direct air to both the first and second fluid conduit segments (27A, 27B;227A, 227B), and the second position closing the fluid conduit junction (27C;227C) to direct air only to the first fluid conduit segment (27A, 27B;227A, 227B); a high pressure compressor section in fluid communication with the low pressure compressor stages to receive pressurized air therefrom and drivingly engaged by a high pressure turbine section ; and an output drive shaft drivingly engaged by the low pressure turbine section . a low pressure compressor section in fluid communication with an air inlet and drivingly engaged by a low pressure turbine section , the low pressure compressor section having low pressure compressor stages spaced apart along an axis of rotation of the low pressure compressor section , and the low pressure compressor section having a fluid conduit extending between the air inlet and the low pressure compression stages , the fluid conduit (27;227) having at least one flow diverter displaceable between a first position and a second position to modulate air flow through the low pressure compressor stages , the fluid conduit (27;227) including a first fluid conduit segment (27A, 27B;227A, 227B) extending between the air inlet and one of the low pressure compression stages , and a second fluid conduit segment (27A, 27B;227A, 227B) extending between the air inlet and another one of the low pressure compression stages , the first and second fluid conduit segments (27A, 27B;227A, 227B) meeting at a fluid conduit junction (27C;227C), the at least one flow diverter positioned about the fluid conduit junction (27C;227C) and displaceable between the first position to direct air to both the first and second fluid conduit segments (27A, 27B;227A, 227B), and the second position closing the fluid conduit junction (27C;227C) to direct air only to the first fluid conduit segment (27A, 27B;227A, 227B); a high pressure compressor section in fluid communication with the low pressure compressor stages to receive pressurized air therefrom and drivingly engaged by a high pressure turbine section ; and an output drive shaft drivingly engaged by the low pressure turbine section . <EOS>