What is the role of self-tests in avionics and which components commonly perform them?

• A. They are optional checks that pilots can skip.
• B. They verify hardware/software health; performed by DMC/ECAM, DTC modules, and system fault checks.
• C. They only test the landing gear hydraulics.
• D. They physically test the flight crew.

Answer: (B)

Self-tests are built-in routines that automatically exercise avionics hardware and software to confirm they are functioning within normal limits. This early fault detection helps ensure systems are ready for flight and makes maintenance more efficient by revealing faults before they affect operations. In practice, these checks are carried out by the Display Management Computer (DMC) and the ECAM system, which monitor overall health and present fault information; by diagnostic test computer (DTC) modules that perform targeted hardware diagnostics; and by ongoing system fault checks that continuously monitor subsystems and log any anomalies. When a fault is detected, ECAM typically displays a fault message and the DTCs provide diagnostic information to guide repair.