AP4 Group – Full-Service Heavy-Duty & Aeroderivative Industrial Gas Turbine Maintenance Provider.

Providing Technical & Labor Services

TC&E - A Division of AP4 Group can provide both the technical supervision and experienced craft labor to calibrate, replace, or upgrade any device associated with your turbine generator set. Our instrument teams consist of a field engineer who is an expert on your control system accompanied by I&C technicians that specialize in power plant instrumentation. As our techs fine tune your instrumentation, our field engineer is ensuring each device is properly looped back to the control system, triggering any associated alarms correctly, and ensuring that the control system is accurately reading every signal by adjusting for any line loss.

We pride ourselves on being the fastest full system calibration contractors in the industry, while maintaining the attention to detail required for turbine generator controls.

Performance Evaluations and Instrument Calibrations:

Did you know that 40% of reported 7F gas turbine reliability issues could have been prevented with valve and instrument upgrades?

Gas and Steam turbines are intricately designed and fine-tuned machines that require precision calibration and maintenance to optimize performance. Minor mis adjustments of electrical and mechanical components can greatly harm the rotating parts and affect output performance which is directly related to MW output and emissions controls. These performance issues are not only damaging to the turbine but can also affect peripheral equipment and cause cascading performance issues across the entire plant impacting MW output and overall revenue.

TC&E can help identify potential issues in performance degradation that lead to loss of MWs and even potential forced outages.  We’re here to help you maximize your plants efficiency and reliability.  This is the best return on your investment in the industry!

In addition to instrumentation calibrations, repair, and upgrades, TC&E can also perform electric gas valve upgrades, replacing hydraulic gas control valves and inlet guide vane (IGV) valves and actuators.


AP4 Power Services specializes in controls, excitation, and LCI systems on GE™ heavy-duty gas and steam turbines. These services include a wide variety of controls maintenance, troubleshooting, and system upgrades. Our OEM-trained field engineers are here to ensure your equipment operations are reliable and efficient.

Power plant personnel look to AP4 Power Services when they are seeking a trusted non-OEM service provider that can help develop and implement customized controls system projects. We are a trusted installation partner for many non-OEM equipment vendors throughout the industry.

From basic troubleshooting to DLE Mapping and mechanical service and maintenance, AP4 Power Services can meet all of your aeroderivative needs. Our expert team of Controls & Mechanical Field Engineers are ready and able to provide the on-site support you require.

Industry Benefits


Using the latest technology, components, and lessons learned through decades of experience, AP4 Power Services can ensure complete reliability for both start-up and continuous operation.


This is the key to success in today’s competitive power markets. Heat Rate, Capacity, Start-Up, and Maintenance Costs are critical to the success of aging power plants.


This is the key to success in today’s competitive power markets. Heat Rate, Capacity, Start-Up, and Maintenance Costs are critical to the success of aging power plants.


Aging systems can continue to provide reliable service for many years to come with the proper service, maintenance, and repairs. Push your upgrades out 5-10 years with confidence.