FAA Aviation Mechanic Airframe (AMA)Airframe InspectionMedium
An owner asks a technician when the emergency locator transmitter (ELT) battery must be replaced or recharged according to 14 CFR 91.207. Which of the following is correct?
- AEvery 24 calendar months regardless of usage
- BAfter 1 cumulative hour of use, or when 50 percent of useful battery life has expired, whichever occurs first
- COnly when the ELT fails a self-test check
- DOnly after the aircraft is involved in an accident
Show answer & explanationAnswer & explanation
Correct answer: B. After 1 cumulative hour of use, or when 50 percent of useful battery life has expired, whichever occurs first
14 CFR 91.207(c) requires ELT batteries to be replaced (or recharged if rechargeable) after 1 cumulative hour of use, or when 50 percent of the battery's useful life (or, for rechargeable batteries, 50 percent of useful life of charge) has expired, whichever occurs first, or per the manufacturer's dates.
Why the other options are wrong
- A. 24 calendar months is not the ELT battery replacement rule; that figure does not apply here.
- C. Self-test failure would require immediate action, but is not the scheduled replacement criterion.
- D. Battery replacement is scheduled, not solely accident-triggered.
ELT Battery Replacement (91.207)
Regulation specifying when an ELT battery must be replaced or recharged based on usage time or expiration of useful life.
- Replace after 1 cumulative hour of use
- Or 50% of battery useful life expired, whichever first
- New expiration date must be marked on battery and recorded in maintenance records
Memory trick: '1 hour or half-life' — whichever hits first wins