If a non-rechargeable ELT battery has reached 50% of its useful life, what should be done?

• A. Replace the battery
• B. Retain the battery until use
• C. Recharge the battery
• D. Ignore until next inspection

Answer: (A)

Non-rechargeable ELT batteries have a limited lifespan and cannot be recharged after they’re installed. As a battery ages, its available energy and ability to deliver peak power decline. Replacing the battery when it has reached 50% of its useful life ensures there will still be sufficient reserve energy if the ELT is ever needed, and it aligns with maintenance guidance that keeps the emergency beacon reliable. Keeping the battery beyond that point risks having insufficient power during an actual emergency. Therefore, you replace it at half of its useful life.