摘要 |
A method of balancing the supply of bleed air from a plurality of gas turbine engines, there being an air bleed line from each of the engines to a common distribution line which distributes the bled air to at least one ancillary system, each air bleed line including a control valve which is controllable by a controller to vary the flow rate of air bled from the associated engine, the method including providing to the controller a demand signal indicative of the demand for bleed air by the ancillary system, sensing air pressure in the distribution line and comparing the demand signal with the sensed air pressure to derive a command signal, flow rates the air pressure individually in each of the air bleed lines from the engines with respective air flow rate sensors which provide air flow rate signals to the controller, comparing the air flow rates in each of the air bleed lines to derive individual flow matching signals for each of the engines, comparing each of the flow matching signals to the command signal to derive a drive signal for each of the control valves, and applying the drive signals to the respective control valves. |