Definition
The physical design of a flight instrument (how it is built, what its internal components are, and how they are arranged) together with the way those components interact to produce an indication on the face of the instrument. Understanding both is required to recognize when an instrument is working correctly, when it is failing, and what its indications actually mean.
Plain English
How an instrument is built inside, and how those parts work together to give you the reading you see on the dial.
Context Anchor
Seen when learning why cockpit instruments show certain indications, not just how to read those indications.
Derivation
Construction comes from a Latin idea meaning “to build together.” Principle comes from a Latin word meaning “beginning” or “foundation.” In this phrase, the words point to the built parts of an instrument and the basic foundation of how it works.
Why Pilots Care
Pilots who grasp these details can interpret instrument indications correctly and recognize when an instrument is malfunctioning.
Intuition Check
This does not mean airport construction or operating rules. Here it means how a flight instrument is built and how it functions.
Example Sentence 1
Before learning to interpret the attitude indicator, the student studied its construction and operating principles so she would understand why it tumbles after extreme maneuvers.
Example Sentence 2
Knowing the construction and operating principles helped the pilot spot the erratic behavior of the altimeter during the approach.