How many rechargeable battery packs power the Emergency Lighting System?

• A. 4 Rechargeable Batteries
• B. 3 Rechargeable Batteries
• C. 5 Rechargeable Batteries
• D. 2 Rechargeable Batteries

Answer: (A)

Emergency lighting is powered by independent rechargeable battery packs that automatically take over if the aircraft’s normal power fails, ensuring the cabin stays illuminated for the required duration during an evacuation. Four battery packs are used to provide enough capacity and redundancy to power all emergency lights across the cabin (exit signs, aisle lighting, floor-level lighting) even if one pack were to fail. They are kept ready by in-flight charging from the aircraft’s electrical system so they’re fully charged when needed. Using four packs balances sufficient power and reliability with weight and cost, whereas fewer packs wouldn’t meet the lighting needs for the entire cabin and more packs would add unnecessary weight.