Under what conditions can a PIC perform a flight under 14 CFR 135 with inoperative equipment?

• A. If the operator has an MMEL with an MEL and a system for deferring the inoperative item.
• B. Whenever the PIC deems it safe.
• C. Only if the item is noncritical.
• D. In no circumstances.

Answer: (A)

The ability to fly with inoperative equipment under Part 135 hinges on an approved deferral system. A PIC may operate with an inoperative item only if the operator has an MMEL (Master Minimum Equipment List) and an associated MEL (Minimum Equipment List) and a formal process to defer the item. The MMEL identifies what items may be inoperative, and the MEL, tailored to the operator’s fleet, provides the specific conditions, time limits, and procedures for deferring those items. With the item included in the MEL and the deferral limits not exceeded, the flight remains within the operator’s approved level of airworthiness.

This is why the option stating you must have an MMEL with an MEL and a deferral system is the correct one. Without that framework, a pilot cannot legally operate with an inoperative item, even if it seems safe, because the regulation requires the approved deferral process. Simply deeming it noncritical or claiming there are no circumstances is not correct, as the MEL defines permissible inoperative conditions and time limits.