Method of operating a gas turbine engine at a low power condition

A method of operating a gas turbine engine, the method comprising:

• driving a compressor to supply pressurized gas to a combustor of the gas turbine engine;
• supplying fuel to a flow divider valve, the fuel supplied to the flow divider valve having a variable fuel pressure;
• controlling a flow of the fuel supplied to the flow divider valve to the combustor of the gas turbine engine via a first manifold and a second manifold of the gas turbine engine so that:
• when the fuel pressure of the fuel supplied to the flow divider valve is greater than a threshold, supplying the fuel supplied to the flow divider valve to the combustor of the gas turbine engine via the first manifold and a plurality of first fuel nozzles associated with the first manifold, and via the second manifold and a plurality of second fuel nozzles associated with the second manifold, during a first mode of operation, the fuel being supplied to the second manifold via a pressure-actuator valve of the flow divider valve configured to prevent the fuel from being supplied to the second manifold when the fuel pressure of the fuel supplied to the flow divider valve is lower than the threshold, and allow the fuel to be supplied to the second manifold when the fuel pressure of the fuel supplied to the flow divider valve is greater than the threshold;
• and
• when the fuel pressure of the fuel supplied to the flow divider valve is lower than the threshold, stopping supply of the fuel supplied to the flow divider valve to the combustor via the second manifold and via the pressure-actuator valve, and continuing to supply the fuel supplied to the flow divider valve to the combustor via the first manifold during a second mode of operation;
• after stopping the fuel supply to the combustor via the second manifold, reversing a flow of the fuel in the second manifold with the pressurized gas inside the combustor at a pressure higher than a pressure of the fuel in the second manifold to drive the fuel in the second manifold upstream and purge the second manifold and the plurality of second fuel nozzles of the fuel;
• and
• supplying the fuel to the first manifold while forcing the fuel purged from the second manifold and from the plurality of second fuel nozzles into a reservoir during the second mode of operation without an ecology pump disposed between the second manifold and the reservoir, the reservoir being defined by a piston movable between an expanded position defining an expanded volume of the reservoir and a contracted position defining a contracted volume of the reservoir.