What are common aircraft battery types?

• A. Lead acid and nickel cadmium.
• B. Lithium-ion and nickel cadmium.
• C. Lead acid, nickel cadmium, and lithium-ion; complete aircraft shutdown before disconnecting batteries.
• D. Alkaline batteries only.

Answer: (C)

The main idea here is understanding which battery chemistries are actually used in aircraft and how maintenance procedures protect safety. Aircraft rely on batteries for starting, power during normal operation, and emergency systems. The common types you’ll encounter are lead-acid, nickel-cadmium (NiCd), and lithium-ion (Li-ion). Lead-acid batteries are traditional, rugged, and capable of delivering strong bursts of current for engine starts. Nickel-cadmium batteries provide reliable performance over a wide temperature range and are durable in aviation environments. Lithium-ion batteries offer higher energy density and lighter weight, and they’re increasingly used in newer aircraft designs, though they require proper management and charging control due to their chemistry.

Alkaline batteries, on the other hand, are not used as primary aircraft power sources. They don’t provide the necessary energy capacity, reliability, or charging compatibility for aviation systems, so they aren’t considered common aircraft battery types.

The safety practice included with the correct choice—shutting down the aircraft before disconnecting batteries—is essential. Power must be removed and systems de-energized to prevent electrical arcing, protect sensitive avionics, and ensure a safe maintenance environment. That combination of listing all three common chemistries and emphasizing a full shutdown before disconnecting captures both what powers aircraft and how to handle maintenance safely.