What does the term INOP indicate in aviation?

The term INOP in aviation stands for "Inoperative". This designation is used to indicate that a piece of equipment or system on an aircraft is not functioning as intended. Generally, the identification of equipment as inoperative is crucial for maintaining safety protocols and ensuring that the aircraft can be operated under regulatory requirements.

When something is marked as INOP, it prompts a detailed assessment of the impact on aircraft performance and safety, guiding crew members and maintenance personnel on necessary actions, which might include further inspections, repairs, or changes to operational procedures. Other options may suggest differing concepts related to operations and conditions, but they do not accurately convey the established aviation terminology that INOP represents.