Aircraft turbine temperature testing is an annual part of turbine engine maintenance. The troubleshooting and performance verification steps that you take could be the difference between an aircraft being safe and having dangerous problems in flight.

Turbine engines work under extreme temperatures, high rotational speeds, and severe vibrations. If the temperature isn't accurately monitored, you could be risking engine operation, fuel efficiency, safety, and the long-term health of the aircraft. These engines have to operate within the design, which comes with temperature tolerances. If the heat exceeds the maximum, engine components can begin to wear at alarming rates. They can stress, crack, or melt. You could even end up with blade failure on your hands.

Temperature data also helps technicians and engineers know what's going on inside the engine during all the crucial stages. It can also help you pinpoint abnormalities in engine performance, which can allow you to correct a small issue before it becomes something much more serious. For example, a rising exhaust gas temperature trend or a reduced EGT margin could reveal fuel control issues or compressor inefficiency.

Common Turbine Temperature Measurements

Aircraft turbine temperature testing changes based on the engine design you're working with. The common ones are TIT, ITT, TGT, and EGT. We'll take a look at some actionable insights for each of these, and then, if you still have questions, you're welcome to give us a call.

Turbine Inlet Temperature (TIT) is what evaluates the temperature of the air entering the turbine section. It will reveal to you how much heat the turbine is being fed after combustion.

Inter-Turbine Temperature (ITT) measures relevant temperatures between turbine stages. It tells you what's happening to the engine's thermal condition during start, acceleration, operation, and any power changes. You'll often see this measurement attached to turboprop and turboshaft engines.

Turbine Gas Temperature (TGT) is what helps you verify that the engine is staying within the expected temperature limits. It's very similar to ITT in that it's used to measure the temperatures inside the turbine section.

Exhaust Gas Temperature (EGT) is the opposite of TIT. EGT measures the temperature of the gases that are leaving the turbine assembly. If EGT margins are abnormal, it means you should be investigating further, since elevated EGT can mean the energy is deteriorating.

Temperature probes are placed at important locations throughout the assembly to capture different measurements. Usually, there is a system of sensors so that different engine zones can be monitored closely to give you a full picture of what's going on.

Key Parameters Monitored During Performance Testing

A full service turbine engine test will reveal so much more than the temperature under the hood. Temperature is just one component of the overall performance, and it reveals one aspect of the engine's structural integrity, yet it is so important. Temperature will impact engine speed, pressure, thrust, torque, fuel flow, and many other operating conditions. You can't have one without the other.

During performance testing, your data acquisition system will collect all the relevant information and present it to you. Your job is to decipher all of those valuable insights and diagnose problems. After that, you simply have to fix the issue and send the aircraft on its way. We're making it sound simple, but it's really a crucial step in any aircraft's maintenance routine.

Preventing Overtemperature Events in Your Aircraft Engines

Perhaps the biggest reason we test turbine engines this way is to prevent overtemperature events. Overtemperature events can happen at any point during the flight, and, if they're not caught right away, they can cause damage to the turbine blades and other components.

Testing also ensures that the pilot has all the relevant information. If everything is working as it should, and the high temperatures are all within the appropriate amounts, then a pilot has the information they need to do well under extreme conditions.

FAA engine certifications are also useful, because it means that your turbine engine has been subjected to certain conditions and is able to perform well under them. The testing you will be doing in your shop is different than the testing that an engine would undergo for a certification, but the standards and regulations that are in place only serve to show that temperature tolerance and turbine engine integrity are crucial to the overall aircraft design.

What Turbine Temperature Test Units Do

Turbine temperature test units are used by aviation mechanics in the proper testing environment to keep their engines operating properly. They do this by using the units to verify the accuracy and the condition of the overall temperature measuring system. They do more than read temperature ratings from the sensors. In fact, they can test thermocouples, indicators, wiring, insulation, and system resistance.

It would be hard to test turbine temperatures without the right equipment. The market is flooded with options, and many of them are engine-specific, so we've compiled just a few things for you to be aware of.

If you want reliable performance regardless of temperature changes or test conditions, the Barfield TT1000A and TT1200A units won't steer you wrong. They each meet unique requirements that make them stand out in the field of aviation maintenance.

It's important to note that they're designed for different types of sensors. The TT1000A simulates Type K thermocouple signals, which will allow you to mimic a running engine so that you can check indicators without turning the aircraft on. The TT1200A, on the other hand, is designed for Chromel-Alumel temperature measuring systems. With it, you can measure resistance and insulation and test indicators.

Having a test set like this will let you figure out exactly where the problem is coming from rather than having to work through everything and hope you find it sooner rather than later. Test units allow you to cut down on busywork, ensuring reliability and safety without wasting a bunch of your time.

At AvionTEq, we can help you find the right equipment for your aircraft and your shop. Not only do we have a wide range of equipment for you to choose from, but we also have different acquisition options. With us, purchasing isn't the only route. We offer renting and leasing for those one-off jobs or sudden workload increases. We also purchase your old equipment so that your shop isn't weighed down with a bunch of irrelevant test units from a past era.

Give us a call, and we can discuss your options!