What must a pilot do with inoperative equipment before flight?

Before flight, if a pilot encounters inoperative equipment, the proper procedure involves deactivating the equipment and placarding it. This action ensures that all crew members and anyone else operating the aircraft are aware of the equipment's status. Placarding serves as a visual reminder and helps maintain safety by clearly communicating that the equipment should not be relied upon during the flight.

Deactivating the equipment further ensures that it does not inadvertently interfere with other systems or operations of the aircraft. For example, inoperative navigation equipment should be deactivated to prevent confusion or incorrect readings. By taking these steps, the pilot upholds safety standards and compliance with regulations, ensuring that both the flight crew and passengers are informed about the aircraft's functional capabilities.

In contrast, simply replacing inoperative equipment immediately is often impractical during a pre-flight check and could lead to time delays, or even the use of unapproved replacement parts if done hastily. Leaving equipment as is without any notice could result in safety hazards if the necessary warnings are not conveyed. Informing the co-pilot, while important for communication, does not address the issue effectively unless the inoperative equipment is also properly placarded and deactivated.