What is the primary indicator of engine health in the TH-73A?

• A. The Fuel Flow gauge
• B. The Gas Producer (NP) RPM gauge
• C. The Torque gauge
• D. The Altitude gauge

Answer: (B)

The Gas Producer (NP) RPM gauge is the primary indicator of engine health in the TH-73A. This gauge measures the rotational speed of the gas producer section of the engine, which is crucial for assessing engine performance and operational efficiency. Monitoring the NP RPM allows pilots to evaluate how effectively the engine is operating, as it provides important insight into engine conditions, including its ability to generate thrust.

If the NP RPM falls outside of the normal operating range, it can indicate potential issues such as fuel starvation, mechanical malfunctions, or other abnormalities in engine performance. Thus, maintaining awareness of the NP RPM is vital for safe flight operations and for preventing possible engine failure.

Other indicators, such as the Fuel Flow gauge, Torque gauge, and Altitude gauge, provide important information; however, they do not serve as the primary indicator of engine health like the NP RPM gauge does. Each of these other gauges has its specific role in flight operations, but the NP RPM gauge is specifically designed to reflect the engine’s operational state, making it the most critical in assessing overall engine health.