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What is CHT in Aviation? (Cylinder Head Temperature (Piston Engine Aviation))

Updated: February 20, 2024

Cylinder Head Temperature (Piston Engine Aviation)

Cylinder Head Temperature (CHT) is a critical parameter in piston engine aviation. It refers to the temperature of the combustion chamber's cylinder head, which houses the spark plug and valves. Monitoring and managing CHT is essential for maintaining engine performance, preventing overheating, and ensuring the longevity of the engine.

CHT is measured in degrees Fahrenheit (°F) or degrees Celsius (°C) using sensors installed on the cylinder heads. These sensors provide real-time data that pilots and mechanics can use to make informed decisions about engine operation and maintenance.

Importance of Monitoring CHT

Monitoring CHT is crucial in piston engine aviation for several reasons:

Preventing Overheating: High CHT can indicate excessive heat in the combustion chamber, which may lead to engine damage or failure. By monitoring CHT, pilots can take corrective action, such as adjusting the mixture or reducing power, to prevent overheating.
Optimizing Performance: CHT is an important parameter for optimizing engine performance. By maintaining CHT within the recommended range, pilots can ensure efficient combustion, maximize power output, and minimize fuel consumption.
Identifying Engine Issues: Unusual CHT readings can indicate potential engine problems, such as a malfunctioning spark plug, a clogged cooling system, or a worn-out valve. Monitoring CHT allows pilots and mechanics to detect and address these issues before they escalate.

Overall, monitoring CHT provides valuable insights into the health and performance of a piston engine, enabling pilots to make informed decisions and take appropriate actions.

Managing CHT

Proper management of CHT is essential for maintaining engine health and performance. Here are some strategies for effectively managing CHT:

Optimizing Mixture: The air-fuel mixture plays a crucial role in controlling CHT. A lean mixture (excess air) can result in higher CHT, while a rich mixture (excess fuel) can lead to lower CHT. Pilots should follow the manufacturer's recommendations for the optimal mixture setting to maintain CHT within the desired range.
Monitoring Power: Power settings significantly impact CHT. Higher power settings generate more heat, increasing CHT. Pilots should carefully manage power settings during different flight phases, considering factors such as altitude, airspeed, and engine load, to keep CHT within the recommended limits.
Cooling System Maintenance: The cooling system, including components such as the radiator and cooling fins, plays a vital role in regulating engine temperature. Regular inspection and maintenance of the cooling system are necessary to ensure proper airflow and cooling efficiency. Any signs of blockage or damage should be addressed promptly.
Proper Engine Break-In: During the initial engine break-in period, it is crucial to follow the manufacturer's guidelines to prevent excessive CHT. This usually involves limiting power and avoiding prolonged high-power operations. By adhering to the break-in procedures, pilots can ensure the proper seating of piston rings and reduce the risk of elevated CHT in the long run.

By employing these management strategies, pilots can effectively control CHT and maintain the engine's health and performance.

For more detailed information on CHT management and best practices, refer to the FAA's Aircraft Maintenance Handbook.


Cylinder Head Temperature (CHT) is a critical parameter in piston engine aviation. Monitoring and managing CHT are essential for preventing overheating, optimizing performance, and identifying potential engine issues. By following proper CHT management practices and utilizing real-time data from CHT sensors, pilots can ensure the longevity and reliability of their engines. Remember to always consult the manufacturer's guidelines and seek professional advice for specific aircraft models and engine types.

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