Definition
Aircraft instruments or equipment that are not functioning correctly and are therefore unusable for flight. Federal regulations (14 CFR 91.213) require that any inoperative item be properly addressed before flight through one of several approved methods, such as a Minimum Equipment List (MEL), the standard inoperative equipment provisions for aircraft without an MEL, or by deactivating, removing, or repairing the item and updating the maintenance records and placards as required.
Plain English
Something on the aircraft that isn't working. Before flying, the pilot must follow specific rules to decide whether the aircraft is still legal and safe to fly with that item not working.
Context Anchor
Seen during preflight inspection, when reviewing aircraft records, looking at cockpit placards, or finding a switch, gauge, light, or system that does not work.
Derivation
From Latin 'in-' (not) and 'operari' (to work). 'Inoperative' simply means 'not working.' In aviation it carries a specific regulatory weight: a not-working item is not just an annoyance, it is a legal and safety issue that must be formally handled before flight.
Why Pilots Care
Determines whether the aircraft meets airworthiness standards for the intended flight under applicable regulations.
Intuition Check
Do not assume “inoperative equipment” means only a major system failure. A small item, such as a light, gauge, or switch, can still count if it is installed and not working.
Example Sentence 1
During preflight, the pilot noticed the landing light was inoperative and checked the regulations and aircraft equipment list to determine whether the flight could legally continue.
Example Sentence 2
The transponder was listed as inoperative equipment so the pilot noted the deviation when filing the flight plan.