What is the primary purpose of trimming a turbine engine?

• A. To adjust idle and trim speed RPM.
• B. To improve fuel efficiency during cruise.
• C. To maximize thrust.
• D. To cool the engine.

Answer: (B)

Trimming a turbine engine is about dialing in the fuel schedule so the engine delivers the desired thrust with the least fuel possible. At cruise, you want the engine to run at its most efficient point, so trimming adjusts fuel flow (and the related spool speeds) to minimize specific fuel consumption while meeting the commanded thrust. It’s not about maximizing thrust, cooling, or merely setting idle speeds—the goal is efficient operation during cruise.