System power failure, tripped breakers, or key-switch lockouts preventing cabin movement.
Sudden mid-shaft stops or safety brake deployments that require fast, skilled emergency triage.
Failure to open or close properly, detector eye faults, or gate operator mechanism jams.
Grinding, squealing, or whining noises pointing to motor degradation or unlubricated components.
Shuddering during transit, uneven travel, or misaligned guide rollers that cause passenger unease.
Stopping unevenly above or below landing doors, creating a high-risk tripping hazard for users.
Unpredictable micro-board glitches, faulty circuit relays, or software communication failures.
Frequent operational dropouts suggesting underlying wear or indicating the need for modernization.