When are the Vent Fans included as part of the ECS?

• A. If the VCCS AC system isn’t installed
• B. Only during takeoff
• C. Only when cabin pressure is high
• D. When the aircraft is on the ground

Answer: (A)

Ventilation in the NGX is handled by the Environmental Control System, and the Vent Fans serve as a fallback option when the main VCCS AC system isn’t installed. In that scenario, the fans provide essential cabin air movement and circulation to maintain ventilation without the primary air-conditioning unit. The other conditions—being tied to takeoff, high cabin pressure, or being on the ground—don’t determine whether the fans are included; it’s specifically about the presence or absence of the VCCS AC system.