If there is no MEL present, what must a pilot do?

When there is no Minimum Equipment List (MEL) available for a specific aircraft, the pilot must refer to the regulations outlined in 14 CFR Part 91.213(d) to determine the required equipment necessary for the flight. This regulation delineates the conditions under which a pilot may operate an aircraft with inoperative instruments or equipment, ensuring safety and compliance with airworthiness standards.

Part 91.213(d) specifies that the pilot must ensure that any equipment required for the aircraft's operation, as outlined in the type certificate, must be operational before undertaking the flight. This ensures that the aircraft meets the necessary safety and operational standards as per regulatory requirements.

The other options do not fulfill the necessary regulatory guidance or may be incomplete. Relying solely on a VFR day type certificate does not encompass all required instruments for operations beyond basic VFR. Ignoring the issue and proceeding without addressing inoperative equipment poses safety risks and violations of regulations, and consulting only with a flight school instructor may not provide the comprehensive regulatory review necessary for safe operation. Hence, using section 91.213(d) is the correct and responsible approach in this situation.