What is OVHT on Boeing 737? (Overheat)

The Boeing 737 is a popular aircraft model used by many airlines around the world. It is known for its reliability and efficiency, making it a preferred choice for both short and medium-haul flights. However, just like any other complex system, the Boeing 737 is equipped with various safety features and warning systems to ensure the well-being of passengers and crew. One of these features is the Overheat system, commonly abbreviated as OVHT.

But what exactly is Overheat, and how does it work in the context of the Boeing 737? In this article, we will delve into the details of Overheat on the Boeing 737, exploring its purpose, components, and implications for flight operations.

Understanding Overheat on the Boeing 737

Overheat, as the name suggests, is a system designed to detect and mitigate potential overheating issues within the aircraft. The system serves as an early warning system, identifying abnormal heat levels in critical areas and alerting pilots to take appropriate actions to prevent any further complications.

The Overheat system on the Boeing 737 is primarily responsible for monitoring critical components such as engines, auxiliary power units (APUs), and environmental control systems (ECS). These components generate significant heat during normal aircraft operation, and any irregularities in their temperature can pose a threat to both the aircraft and its occupants.

To efficiently monitor temperatures, the Overheat system relies on temperature sensors strategically placed throughout the aircraft. These sensors continuously measure the temperature of specific components and provide real-time data to the aircraft’s central computer system.

Components of the Overheat System

The Overheat system on the Boeing 737 comprises several key components, each playing a crucial role in maintaining the aircraft’s safety. Let’s take a look at these components:

1. Temperature Sensors: As mentioned earlier, temperature sensors are strategically placed throughout the aircraft to monitor the temperature of critical components. These sensors provide data to the aircraft’s computer system, enabling it to make informed decisions based on real-time temperature readings.

2. Warning Lights and Alarms: When the Overheat system detects abnormal heat levels, it triggers warning lights and alarms in the cockpit, immediately notifying the flight crew of the potential issue. This allows the crew to take prompt actions to address the situation before it escalates.

3. Circuit Breakers: In the event of an overheating situation, circuit breakers act as a safety mechanism to prevent further damage. They are designed to interrupt the flow of electrical current to specific components, isolating them from the rest of the system.

4. Overheat Displays: The Boeing 737 cockpit features dedicated Overheat displays, which provide detailed information about the temperature status of various components. These displays enable the flight crew to quickly assess the situation and make informed decisions.

It is important to note that the Overheat system is just one of many safety features present on the Boeing 737. It works in conjunction with other systems and procedures to ensure the overall safety and reliability of the aircraft.

The Implications of Overheat on Flight Operations

The Overheat system plays a critical role in flight operations, as it helps prevent potential hazards associated with overheating components. By detecting abnormal heat levels early on, the system allows pilots to take appropriate actions to mitigate any risks and ensure the safety of the aircraft and its occupants.

Overheating can have various implications depending on the specific component involved. For example, if an engine overheats, it could lead to engine damage or even failure. In such cases, the Overheat system would alert the flight crew, enabling them to shut down the affected engine and ensure the aircraft’s continued safe operation.

Similarly, overheating in the APU or ECS can have negative consequences. The APU provides electrical power for various aircraft systems when the engines are not running, and the ECS is responsible for maintaining a comfortable cabin environment. Any issues with these systems can result in disruptions to electrical power supply or cabin temperature control, affecting the overall flight experience.

By continuously monitoring critical components, the Overheat system allows for proactive identification and resolution of potential issues before they escalate. This not only prevents in-flight emergencies but also reduces the likelihood of costly repairs and maintenance downtime.


The Overheat system plays a significant role in maintaining the safety and reliability of the Boeing 737 aircraft. By monitoring critical components for abnormal heat levels, the system provides early warnings to the flight crew, enabling them to take prompt actions and prevent potential hazards.

Understanding the components and implications of the Overheat system is essential for pilots, maintenance crews, and aviation enthusiasts alike. With its proactive approach to detecting overheating issues, the Overheat system contributes to the overall efficiency and safety of Boeing 737 flights.

For More: What is CIWS on Boeing 737? (Central Instrument Warning System)