FAA Private Pilot Helicopter (PRH)Navigation and AirspaceEasy
A helicopter is equipped with an emergency locator transmitter (ELT) that was activated inadvertently during a hard landing and operated for 45 minutes before being shut off. According to 14 CFR 91.207, what maintenance action is required regarding the ELT battery?
- AThe battery must be replaced or recharged after 1 cumulative hour of use, or when 50% of its useful life has expired, whichever occurs first
- BThe battery only needs replacement if the ELT was used for more than 4 hours total
- CThe ELT unit itself must be replaced entirely regardless of battery condition after any activation
- DNo action is required since the ELT operated less than 1 cumulative hour
Show answer & explanationAnswer & explanation
Correct answer: A. The battery must be replaced or recharged after 1 cumulative hour of use, or when 50% of its useful life has expired, whichever occurs first
14 CFR 91.207 requires that an ELT battery be replaced (or recharged, if rechargeable) after 1 cumulative hour of use, or when 50% of the battery's useful life (or useful life of charge) has expired, whichever occurs first. In this case, the 45-minute activation counts toward that cumulative hour.
Why the other options are wrong
- B. The correct threshold is 1 cumulative hour, not 4 hours.
- C. Only the battery, not necessarily the entire unit, must be replaced per this rule.
- D. The 45-minute use counts cumulatively toward the 1-hour limit, and battery life must still be tracked.
ELT Battery Replacement Rule (91.207)
An ELT battery must be replaced/recharged after 1 cumulative hour of use or 50% of useful life, whichever comes first.
- Applies to both used and standby battery life
- Replacement date must be marked on the ELT or its container
- ELTs transmit on 121.5 and 406 MHz depending on type
Memory trick: 1 hour used or half the life — replace that battery, avoid the strife.