What must not be used to locate defects during inspections?

Using train documents to locate defects during inspections is not appropriate because train documents primarily provide administrative and operational information rather than real-time technical data or indications of defects. They may include schedules, maintenance history, and operational protocols, but they do not replace the need for hands-on inspections or direct observation of the equipment.

In contrast, inspection tools, audio alerts, and visual checks are specifically designed for identifying defects. Inspection tools can include gauges, calipers, and other instruments that provide precise measurements or observations. Audio alerts can indicate malfunctions through audible signals, while visual checks rely on direct observation of the equipment to identify any visible issues. Each of these methods plays a critical role in thorough and effective inspections, ensuring the safety and functionality of the equipment.