Which component provides the thrust limit modes with reference to N1 in normal operation?

Which component provides the thrust limit modes with reference to N1 in normal operation?

• A. APU
• B. FADEC
• C. Engine control unit
• D. Hydraulic system

Answer: (B)

Thrust limit modes that reference N1 are implemented by the FADEC, the Full Authority Digital Engine Control. The FADEC continuously monitors N1 (the low‑pressure spool speed) along with other parameters and uses N1 as the basis for the maximum allowable thrust. When a thrust request would push N1 toward or beyond its limit, the FADEC trims fuel flow to keep N1 at the safe limit, providing the appropriate takeoff, climb, or other normal operation settings. The FADEC is the electronic control system that manages engine performance and protection, so it’s the component responsible for enforcing N1‑based thrust limits. The APU and hydraulic system don’t control thrust, and while the engine control unit concept is related, the FADEC is the specific system handling these limits.

Thrust limit modes that reference N1 are implemented by the FADEC, the Full Authority Digital Engine Control. The FADEC continuously monitors N1 (the low‑pressure spool speed) along with other parameters and uses N1 as the basis for the maximum allowable thrust. When a thrust request would push N1 toward or beyond its limit, the FADEC trims fuel flow to keep N1 at the safe limit, providing the appropriate takeoff, climb, or other normal operation settings. The FADEC is the electronic control system that manages engine performance and protection, so it’s the component responsible for enforcing N1‑based thrust limits. The APU and hydraulic system don’t control thrust, and while the engine control unit concept is related, the FADEC is the specific system handling these limits.