A gas turbine engine is disclosed that has with two or more compressors. A first one of the compressors include a compressor variable geometry mechanism that may be in the form of adjustable vanes, bleed valves, or the like. A first one of the compressors is turned at a first speed and the second one of the compressors is turned at a second speed. The first speed is maintained approximately constant while the second speed varies and position of the compressor variable geometry mechanism is modulated in accordance with the second speed of the second one of the compressors to regulate surge margin for the first one of the compressors.
展开▼
