Which of the following is an FADEC advantage?

• A. Requires no engine trimming.
• B. Constant idle speed with changes in conditions.
• C. Fully modulates active clearance control.
• D. Lowers fuel efficiency.

Answer: (B)

Holding idle speed constant as conditions change is a key benefit of FADEC. The digital engine control constantly monitors parameters like engine speed, temperatures, and ambient conditions, then precisely adjusts fuel flow and ignition timing to keep the idle target RPM. This automatic adjustment keeps idle steady when air density, bleed load, or engine wear vary, and it reduces the need for manual trimming and throttle input. The other statements aren’t as accurate: trimming isn’t entirely eliminated, active clearance control is a separate subsystem rather than something FADEC fully modulates, and FADEC’s aim is to improve efficiency and control rather than lower fuel efficiency.