Definition
An inspection tool used to quickly determine whether a part falls within acceptable size limits. It has two test ends or features: the 'go' end must fit or pass over the part, and the 'no-go' end must not. If the part passes both tests correctly, it is within tolerance; if it fails either test, the part is rejected.
Plain English
A simple measuring tool that tells you 'yes, this part is the right size' or 'no, it isn't' without giving you an exact number. One end should slip on, the other end should not.
Context Anchor
Seen in aircraft maintenance, especially when checking holes, pins, bolts, threads, or other parts that must stay within a specific size range.
Derivation
The name comes straight from how the tool is used: one end is the 'go' (it should go on or in), the other is the 'no-go' (it should not). The tool answers a pass/fail question rather than producing a measurement.
Why Pilots Care
Confirms that critical aircraft parts meet exact size requirements before installation, reducing the risk of mechanical failure.
Analogy
Think of a coin slot on a vending machine. A quarter goes in; a half-dollar doesn't. The slot isn't measuring the coin in millimetres — it's just sorting acceptable from unacceptable.
Intuition Check
Do not read “go, no-go” here as a flight decision by itself. In this term, it means a physical measuring tool that gives a pass/fail result for a part’s size.
Example Sentence 1
The mechanic used a go, no-go gauge to check whether the worn bolt holes were still within tolerance.
Example Sentence 2
When the no-go end slid over the shaft, the part was rejected and replaced.