Definition
The period of time during which a component, fluid, or material remains usable for its intended purpose before it must be replaced, recharged, overhauled, or discarded. For consumables such as adhesives, sealants, or batteries, working life refers to the usable time after activation or installation. For mechanical parts, it refers to the service time between required overhauls or retirement.
Plain English
How long something stays good and can keep doing its job before it has to be replaced or refreshed.
Context Anchor
Seen in aircraft maintenance instructions, especially when using mixed materials such as sealants, glues, resins, or coatings.
Why Pilots Care
Using a component beyond its working life can cause it to fail in service. Pilots and mechanics rely on these limits to know when a part or product is still safe to trust and when it must be retired.
Analogy
It is like mixed glue from a hardware store: once you mix it, the clock starts, and after a certain time it no longer spreads or sticks correctly.
Intuition Check
Working life does not mean how long the finished repair or part will last in service. It means how long the material remains usable after it is prepared or mixed.
Example Sentence 1
The fuel tank sealant has a working life of two hours after mixing, so the technician applied it quickly before it began to cure.
Example Sentence 2
Track each tire's working life by landings to ensure replacement before wear limits are reached.