Originally Posted by
Techo27
Sorry guys, the fuel control system of any gas turbine engine requires 5 basic inputs for self control either by FADEC or the Fuel control unit itself. These are a reference of PT2 and TT2 for air density, N2 Rpm, Throttle position and PB (Combustion chamber pressure) to prevent engine stall during acceleration. Supersonic aircraft need one additional control factor and that is MA (Mach number) to prevent excessive air entering the engine intake when aircraft airspeed is above Mach.
All other parameters such as N1 Rpm, TIT, FF, PT7 or Oil Pressure are simply for indication to the pilot of the state of his engine EG N1 RPM or PT7-PT2 when converted to an EPR is used to inform the flight crew how much power the engine is producing with FF used as a cross reference. OIl pressure and TIT is simply to inform the aircrew on the state of the engine in regards to oil pressure and operating temperature. Some FADEC systems are designed with software to control any condition outside normal, by warning the aircrew and automatically retarding fuel flow to prevent engine over speeds and over temps and also relight the engine if it flames out during aggressive maneuvering or abnormal atmospheric conditions if throttle position is in flight idle or above.
Firstly, not sure why you are saying sorry. Your post is interesting.
Probably the most important parameter on a very modern Gas Turbine engine as far as control would be Turbine Entry Temperature, or actual Turbine Blade Temperature in the case of optical pyrometer sensor (RB199 & EJ200).
That would be to limit fuel flow as the temperature reached a limiting value.
It would also provide for surge indication in the event of cooling flow interruption.
So, TIT assuming you mean Turbine Inlet Temperature is far more than just an indication to the pilot.
It would be an essential control parameter.