Motoring synchronization for multiple engines

1. A method for motoring control for multiple engines of an aircraft, the method comprising:

determining, by a controller, a motoring time of a first engine starting system to cool a first engine;

comparing, by the controller, the motoring time of the first engine starting system with a motoring time of one or more other engine starting systems of one or more other engines of the aircraft; and

controlling the motoring time of the first engine starting system relative to a tolerance of the motoring time of the one or more other engine starting systems by adjusting the motoring time of the first engine starting system relative to the one or more other engine starting systems in a motoring sequence based on comparing the motoring time of the first engine starting system with the motoring time of the one or more other engine starting systems.

2. The method of claim 1 , wherein the motoring time of the first engine starting system is controlled relative to the one or more other engine starting systems by comparing a first value of the motoring time of the first engine starting system with a first value of the motoring time of the one or more other engine starting systems and selecting a larger value as the motoring time for the first engine starting system and the one or more other engine starting systems.

3. The method of claim 2 , further comprising:

providing the first value of the motoring time of the first engine starting system to one or more other controllers; and

receiving the first value of the motoring time of the one or more other engine starting systems from the one or more other controllers.

4. The method of claim 2 , further comprising:

maintaining the motoring time of the first engine starting system as a first value of the motoring time of the first engine starting system based on determining that the first value of the motoring time of the first engine starting system is greater than or equal to the first value of the motoring time of the one or more other engine starting systems.

5. The method of claim 1 , wherein the motoring sequence comprises simultaneous motoring of the first engine and the one or more other engines.

6. The method of claim 1 , wherein the motoring sequence comprises sequential motoring of the first engine and the one or more other engines.

7. The method of claim 1 , further comprising:

controlling the first engine starting system to maintain a spool speed of the first engine below a resonance speed during the motoring time of the first engine starting system.

8. The method of claim 7 , wherein the motoring time of the first engine starting system is determined by the controller using a bowed rotor start risk model based on one or more of: a target speed, a current engine temperature, and an ambient temperature.

9. The method of claim 1 , further comprising:

validating the motoring time of the one or more other engine starting systems.

10. The method of claim 9 , further comprising:

range limiting the motoring time of the first engine starting system prior to performing motoring of the first engine during the motoring sequence.

11. A method comprising:

controlling, by a first controller, a first starter of a first engine system to perform motoring of a first gas turbine engine in a motoring sequence to cool the first gas turbine engine;

controlling, by a second controller, a second starter of a second engine system to perform motoring of a second gas turbine engine in the motoring sequence to cool the second gas turbine engine; and

adjusting a motoring time of the first gas turbine engine relative to a motoring time of the second gas turbine engine based on comparing the motoring time of the first gas turbine engine with the motoring time of the second gas turbine engine, wherein the motoring time of the first gas turbine engine is controlled within a tolerance of the motoring time of the second gas turbine engine.

12. The method of claim 11 , wherein the motoring time of the first gas turbine engine is coordinated relative to the motoring time of the second gas turbine engine by at least one engine control interface.

13. The method of claim 11 , further comprising:

exchanging, by the first controller and the second controller, first values of the motoring time of the first gas turbine engine and the motoring time of the second gas turbine engine.

14. The method of claim 13 , further comprising:

selecting a larger value as the motoring time of the first gas turbine engine and the motoring time of the second gas turbine engine.

15. The method of claim 11 , wherein the motoring sequence comprises simultaneous motoring of the first gas turbine engine and the second gas turbine engine.

16. The method of claim 11 , wherein the motoring sequence comprises sequential motoring of the first gas turbine engine and the second gas turbine engine.

17. The method of claim 11 , further comprising:

controlling the first engine system to maintain a spool speed of the first engine below a resonance speed during the motoring time of the first engine system.

18. The method of claim 11 , further comprising:

validating and range limiting the motoring time of the first gas turbine engine prior to performing motoring of the first gas turbine engine during the motoring sequence.

19. The method of claim 18 , further comprising:

validating and range limiting the motoring time of the second gas turbine engine prior to performing motoring of the second gas turbine engine during the motoring sequence.