Definition
A grouping of the four core operational concerns the FAA balances when planning, designing, or modifying airports and the surrounding airspace: capacity (how much traffic the system can handle), safety (protecting people and aircraft from harm), security (protecting against intentional threats), and noise (managing the impact of aircraft sound on surrounding communities).
Plain English
A short way of listing the four big things the FAA looks at when making decisions about airports and airspace: how much traffic it can handle, how safe it is, how secure it is, and how much noise it makes.
Context Anchor
Seen in NOTAMs and FAA abbreviation lists when a short code is used to explain why an operation is limited or changed.
Why Pilots Care
Decisions framed around C/S/S/N drive things pilots actually feel: runway extensions, new approach procedures, noise abatement routes, curfews, and security restrictions at certain airports.
Intuition Check
Do not read C/S/S/N as the name of one piece of equipment or one single system. In this FAA context, the slashes separate four possible operational reasons: capacity, safety, security, and noise.
Example Sentence 1
The airport's expansion proposal was evaluated against C/S/S/N criteria before approval.
Example Sentence 2
Noise emerged as the dominant issue in the C/S/S/N review for the new terminal.