FAR 23.2605 — Equipment Installation and Operation

FAR 23.2605 sets the basic ground rules for how equipment in a Part 23 airplane must be installed and how it communicates with the pilot. It's a certification standard, but understanding it helps you make sense of why your flight deck looks and behaves the way it does.

The rule has three core requirements:

• Labeling: Every item of installed equipment tied to the flightcrew interface (switches, controls, indicators) must be labeled with its identification, function, or operating limitations — whatever applies.
• System indications: There must be a discernible means of showing the operating parameters needed to fly the airplane. That includes warnings, cautions, and normal indications delivered to the crewmember responsible for that system.
• Unsafe condition alerts: If a system enters an unsafe operating condition, the information must reach the responsible crewmember in a timely manner and be clear enough to prevent likely pilot errors.

Operationally, this is why you can trust that a red light means act now, an amber light means be aware, and every switch on the panel tells you what it does — the design was certified to make the right action obvious.