What does the torque indicating system in a turbine engine measure?

The torque indicating system in a turbine engine is designed to measure the amount of torque produced by the engine while it is functioning. This measurement is directly related to indicated shaft horsepower, as torque is a key component in determining horsepower. The relationship is defined by the formula: Horsepower = Torque × RPM / 5252, which illustrates how torque contributes to the power output of the engine at a given rotational speed.

Indicated shaft horsepower is an important parameter that helps operators understand the engine's performance capabilities. By measuring the torque, the system provides valuable data on the effectiveness of the propulsion system and ensures that the engine operates within its designed limits. This is crucial for safe and efficient operations, especially during critical phases of flight such as takeoff and climbing.

The other choices do not align with the purpose of the torque indicating system. Airflow rate is measured by other sensors that detect the mass flow of air through the engine. Fuel flow rate is monitored by different instrumentation specifically designed to measure the amount of fuel being supplied to the combustion chamber. Lastly, combustion temperature falls under different parameters that assess engine efficiency and combustion performance, but it doesn't relate to the torque produced by the turbine's shaft.