What does the asterisk symbol in column 4 of an MEL signify for maintenance personnel?

The asterisk symbol in column 4 of a Minimum Equipment List (MEL) signifies that if the associated item of equipment is inoperative, it must be placarded. This is an important requirement for maintenance personnel because placarding communicates to flight crews and maintenance staff that the item is not functioning and should not be used during operations. In addition, placarding helps ensure compliance with safety regulations and informs all parties of the status of the equipment, minimizing confusion and potential safety risks.

While other options may contain relevant information concerning the MEL or its components, the specific function of the asterisk regarding the need for placarding when an item is inoperative is critical for maintaining safety and regulatory compliance in aviation operations.