Definition
A precision measuring tool used to determine the depth of a hole, slot, recess, or shoulder in a part. Aviation maintenance technicians use depth gauges to measure features such as cylinder wear ridges, counterbore depths, and the seating of components within an engine or airframe assembly.
Plain English
A tool that measures how deep a hole or recess goes. The technician sets it against the surface and reads how far down the bottom of the hole is.
Context Anchor
Seen in aircraft maintenance, inspection, and repair work when a mechanic needs to measure the depth of a part feature or damage area.
Derivation
From 'depth' (how far down something goes) and 'gauge' (a tool that measures). The name describes exactly what it does.
Why Pilots Care
Determines whether damage exceeds manufacturer limits, preventing potential propeller or engine failure in flight.
Grounding Statement
A depth gauge measures downward from a known surface to show how far below that surface something is.
Intuition Check
Do not read this as a gauge for water depth or as any gauge with deep markings. In aircraft work, a depth gauge is a tool for measuring how far below a surface a hole, groove, recess, or damage mark goes.
Example Sentence 1
The mechanic used a depth gauge to measure the wear ridge inside the cylinder before deciding whether it could be returned to service.
Example Sentence 2
Using the depth gauge on the cylinder wall showed the wear remained within acceptable limits.