Which system provides breathable gas to the aircrew?

• A. OBOGS
• B. Cabin pressurization
• C. Windshield defog
• D. Radar liquid cooling

Answer: (A)

Breathable gas for the aircrew comes from a dedicated oxygen system, the On-Board Oxygen Generating System. This system creates oxygen-enriched gas and delivers it through the aircrew’s mask, automatically adjusting flow to maintain the proper oxygen level as altitude changes. It’s designed to provide a reliable supply of breathable gas without relying on external bottles, which is essential for high-altitude operation.

Cabin pressurization, while it maintains cabin pressure and supplies conditioned air to everyone aboard, does not directly provide the aircrew’s respirable gas at the required partial pressure. Windshield defog uses airflow to clear the windshield, and the radar liquid cooling system handles cooling for radar components—neither is about supplying breathable oxygen.