What is TCC on Boeing 737? (Turbine Case Cooling)

Turbine Case Cooling (TCC) is an essential component of the Boeing 737 aircraft, playing a crucial role in maintaining the optimal operating temperature of the engine. It is a system that ensures adequate cooling of the engine’s turbine case, which houses critical components such as the high-pressure turbine (HPT) and low-pressure turbine (LPT). This article will explore the importance of Turbine Case Cooling on the Boeing 737 and delve into its functioning and significance in ensuring safe and efficient flight operations.

How Does Turbine Case Cooling Work?

Within the engine of a Boeing 737, the turbine case is subjected to extreme temperatures due to the high heat generated during the combustion process. The Turbine Case Cooling system consists of multiple bleed air ducts that extract a small portion of compressed air from the engine compressor section. This extracted air is then directed to the turbine case through specialized cooling air passages.

The purpose of this cooling air is to lower the temperature of the turbine case and prevent excessive heat buildup, which could potentially damage the engine components. The cooling air absorbs the heat from the turbine case and is expelled overboard through exhaust vents, dissipating the absorbed heat into the atmosphere. This continuous flow of cooling air ensures that the turbine case remains within the safe temperature limits, thereby maintaining the structural integrity of the engine.

Moreover, the cooling air also serves another vital function by sealing the turbine case, reducing the risk of oil leaks. By maintaining a higher pressure inside the turbine case than the surrounding areas, the cooling air acts as a barrier, preventing oil from escaping and potentially causing damage to other engine components.

Significance of Turbine Case Cooling on Boeing 737

The Turbine Case Cooling system on the Boeing 737 holds immense significance in ensuring the safe and efficient operation of the aircraft. Let’s explore some key reasons why:

1. Temperature Regulation

The primary purpose of Turbine Case Cooling is to regulate the temperature of the turbine case. The turbine case experiences extreme heat due to the combustion process, and without proper cooling, it can lead to thermal stress and potential failure of critical engine components. By maintaining the turbine case temperature within the specified limits, the TCC system enhances the overall reliability and longevity of the engine.

2. Enhanced Performance

Efficient cooling of the turbine case also contributes to improved engine performance. By ensuring that the critical components operating within the turbine case are maintained at the optimal temperature range, the TCC system allows them to function at their peak efficiency. This, in turn, leads to better fuel consumption, reduced emissions, and overall enhanced performance of the Boeing 737 aircraft.

3. Safety and Reliability

The safety and reliability of the Boeing 737 are of utmost importance, and the Turbine Case Cooling system contributes significantly to achieving these objectives. By preventing excessive heat buildup, the TCC system enhances the structural integrity of the engine and reduces the likelihood of catastrophic failures. This ensures a higher level of safety for both the passengers and crew onboard.

Furthermore, the sealing effect of the cooling air plays a vital role in preventing oil leaks that could result in engine malfunctions or fires. This additional layer of protection adds to the reliability of the engine, reducing the risk of in-flight emergencies and ensuring smooth operations throughout the flight.


In summary, Turbine Case Cooling (TCC) is a crucial system on the Boeing 737 that regulates the temperature of the turbine case, preventing excessive heat buildup and ensuring the safe and efficient operation of the aircraft. Through its cooling air passages, the TCC system extracts compressed air and directs it to the turbine case, actively dissipating heat and maintaining optimal temperature levels. This system’s significance lies in its ability to enhance engine performance, ensure operational safety, and increase the overall reliability of the Boeing 737 aircraft.

For more technical information on the Turbine Case Cooling system and its functioning, you can visit the official Boeing 737 website here.

For More: What is FMS on Boeing 737? (Flight Management System)