Which scenario best illustrates the use of degraded mode?

• A. All subsystems operate at full capacity without any faults.
• B. One subsystem operates at reduced capability while essential functions remain available.
• C. The entire system is offline.
• D. The ship relies on manual backups with no automation.

Answer: (B)

Degraded mode is about preserving essential functions when a fault or limitation forces the system to trim back noncritical capabilities. It keeps the critical operations running, even if overall performance is reduced.

That scenario fits best because one subsystem is operating at reduced capability while the essential functions remain available. It shows the system prioritizing what must work and dialing down other parts to maintain core operation.

Normal full-capacity operation isn’t degraded mode, since nothing is reduced. A system fully offline isn’t degraded mode either—it’s shutdown. Relying on manual backups with no automation describes a different kind of manual or alternate operation rather than the automated, prioritized reduction characteristic of degraded mode.