Which of the following criteria is NOT used to determine the replacement of life-limited turbine engine components?

The criteria for determining the replacement of life-limited turbine engine components are primarily based on operational usage metrics such as cycles, flight hours, and calendar time.

Cycles refer to the number of starts and stops an engine has experienced, as this can create stress on engine components, leading to potential fatigue failures. Flight hours are the total time an engine has been operating, which can quantify wear and degradation. Calendar time reflects the time elapsed since the component was put into service, acknowledging that even unused components have a finite lifespan due to factors like material degradation over time.

The essence of these criteria is rooted in the operational history and aging of the components, which helps in ensuring safety and reliability in engine performance.

In contrast, the brand of the engine is irrelevant in determining the life limits of its components; different manufacturers might have their own specifications and guidelines, but the fundamental parameters for assessing component life remain the same across different brands. Therefore, engine brand does not participate as a criterion for replacement, as it does not provide a consistent measurement of engine performance or component reliability.