What is the maximum number of PDI's possible if the utility pump is not installed?

The question pertains to the number of Potential Drainage Indications (PDIs) that can be assessed when the utility pump is not installed. In an aircraft maintenance context, PDIs represent various checks and measures that need to be taken to ensure the system's integrity and functionality.

The correct answer indicates that there can be a maximum of 12 PDIs when the utility pump is absent. This figure can be derived from the specific maintenance and operational guidelines set forth for the system in question. The limit on PDIs in the absence of the utility pump reflects system design and operational requirements that ensure safe and efficient operation without that pump.

Understanding that the presence or absence of equipment like the utility pump alters operational parameters is critical. The figures provided in the other answers reflect scenarios where the utility pump is installed or operational, which allows for more PDIs. Consequently, those higher numbers do not apply when the pump is not in place. Hence, realizing that the 12 PDIs are representative of the system's operational modifications underscores the importance of this figure as a limit in the absence of the utility pump.