Define an electrical load shed scenario and its effect on aircraft systems.

• A. In a power-constrained event, non-essential systems are de-energized to preserve power for critical operations and safety-related systems
• B. A routine test of electrical circuits
• C. When all systems are powered equally
• D. When battery is replaced

Answer: (A)

Load shedding is the deliberate de-energizing of non-essential electrical loads when power is limited, so critical operations and safety-related systems stay powered. In an electrical power-constrained scenario, the aircraft’s power management system prioritizes essential buses—flight controls, primary flight instruments, essential avionics, and critical communications and navigation—while non-essential systems such as cabin lighting, galley services, and some non-critical displays may be temporarily shed. This preserves the available generation or battery energy for the parts of the system that must operate for safe flight. The effect on aircraft systems is that you continue to have the vital indications and controls, but some comfort features and non-critical equipment may be unavailable until power is restored. It is not a routine test, not a situation where every system is powered equally, and it does not describe simply replacing a battery.