If a gas turbine has operated at 85% RPM for more than 1 minute prior to shutdown, what should you do?

When a gas turbine operates at a reduced RPM, especially at 85% for an extended period before shutdown, it is important to allow the engine to stabilize and cool down properly to prevent potential damage. Operating at idle for 5 minutes allows the turbine to gradually transition to a lower RPM while ensuring that internal components reach a more uniform temperature. This process can help minimize thermal stresses and prevent issues such as distortion or a rapid temperature drop, which can lead to mechanical failures.

Running the turbine at idle post-operation is a standard procedure that allows for proper cooldown and helps in the eventual stabilization of engine conditions before complete shutdown. This practice is aligned with the operational protocols often outlined in the maintenance manuals for gas turbines, emphasizing the need for proper cooling cycles to prolong engine lifespan and optimize performance.