FAR 23.2320 — Occupant Physical Environment
FAR 23.2320 sets Part 23 design rules for cabin environment: communication, windshield impact, breathable air, pressurization, and oxygen systems.
FAR 23.2320 is a Part 23 airworthiness design standard that tells manufacturers how to protect occupants inside the cabin. While you won't be tested on it like an operating rule, understanding it helps explain why your airplane is built the way it is.
The applicant (manufacturer) must design the airplane to:
- Allow clear communication between flightcrew and passengers
- Protect the pilot and flight controls from propellers
- Protect occupants from serious injury caused by damage to windshields, windows, and canopies
For Level 4 airplanes, the windshield and its supporting structure directly in front of the pilot must withstand a two-pound bird strike at the airplane's maximum approach flap speed without penetration.
The cabin must provide every occupant with air at a breathable pressure, free of hazardous gases, vapors, or smoke — both in normal ops and likely failure scenarios.
If a pressurization system is installed, it must guard against decompression to an unsafe level and against excessive differential pressure. If an oxygen system is installed, it must effectively prevent hypoxia and be free from hazards in its design, operation, or effect on other systems.