With both generators and batteries inoperative, what systems can we expect to work?

• A. Passenger O2, the pressurization controller, and the ESIS
• B. GPS, Com 1, and MFD
• C. HVAC, Cabin Lights, and Wipers
• D. Engine oil pressure, Hydraulic pump, and AIS

Answer: (A)

When power is completely lost, only systems tied to the emergency/essential power remain active. The PC-12 NGX is designed so certain critical functions stay powered by a separate emergency power source, allowing continued operation of a limited set of systems for a period of time.

The passenger oxygen system is independent of normal electrical power because it relies on stored oxygen and a mechanical/chemical delivery path, so it remains available for occupants. The pressurization controller is part of the essential cabin systems and is kept alive on the emergency power to maintain safe cabin conditions as much as possible. The ESIS (Electronic Standby Instrument System) provides key flight instruments from the standby power supply, so you still have essential attitude and altitude information.

Other systems you rely on for regular flight operations, such as GPS, radio communications, primary displays, HVAC, lighting, and various engine or hydraulic indicators, depend on the normal electrical system and would not be expected to function without generators or batteries.