The on Friday will publish a directive giving operators 10 days to inspect emergency locator transmitters (ELTs) or remove them from service.
The agency’s airworthiness directive (AD), triggered by the July 12 fire on an787 at , orders checks of the ELT, its lithium-manganese-dioxide battery and “associated wiring” for “discrepancies.”
In a statement last week, the FAA said the checks would look for proper wire routing and any signs of wire damage or “pinching,” as well as “unusual” signs of heating or moisture in the ELT battery compartment.
Last week’s statement did not discuss removing ELTs as an option to comply.
Preliminary conclusions in a U.K. Air Accidents Investigation Branch (AAIB)-led probe determined that the fire’s source was most likely a wire short circuit or an issue with the ELT’s battery, though the investigation is continuing.
The AD applies only to in-service aircraft and technically covers only six787s, as the carrier is the only one operating U.S.-registered models, which must comply with FAA ADs. Other authorities are expected to adopt FAA’s directive or a similar order, effectively spreading the mandate worldwide.
Some operators, acting on AAIB’s initial reports, are ahead of regulators.
United has visually inspected its aircraft and reported no findings of problems so far.
The FAA notes that while the AD applies to 787s, the presence of the Honeywell device on other models means “continuing investigation is required,” which could lead to additional directives. Honeywell has produced about 6,000 of the ELTs in question.
AAIB notes that the Ethiopian Airlines incident “has been the only significant thermal event.” Nevertheless, based on initial findings AAIB recommended that FAA review lithium-powered ELT systems on all aircraft and, if necessary, take action.