U.S. Authorities Prepare To Order Inspections on 787 ELTs

 - July 22, 2013, 12:30 PM
The first Ethiopian Boeing 787 takes off on a test flight from Charleston, South Carolina. (Photo: Boeing)

The U.S. Federal Aviation Administration said on Friday it plans to order inspections of the wiring associated with the emergency locator transmitters (ELTs) on Boeing 787s following a recommendation from the UK’s Air Accidents Investigation Branch that operators disable the airplanes’ Honeywell-made systems. An Advisory Directive scheduled for publication today would require inspection for proper wire routing and damaged or pinched wires, the statement said. Operators would also need to inspect the transmitter’s battery compartment for condensation or overheating.

It took the AAIB less than a week after the July 12 fire aboard an Ethiopian Airlines 787 parked at London Heathrow Airport to recommend either removal or disconnection of the ELT in all sixty-eight 787s in service after it found most of the fire damage near the Honeywell system and its associated wiring, mounted internally on structure near the skin of the rear fuselage section. The AAIB further noted that no other systems in the area contain enough stored energy to start a fire.

Detailed examination of the ELT has shown some indications of “disruption” of the battery cells, said the agency. However, the AAIB hasn’t concluded whether the damage resulted from a release of energy within the batteries or an external mechanism such as an electrical short.

By the end of last week, the FAA hadn’t yet issued a directive, leaving the two 787 operators in Japan–all Nippon Airways and Japan Airlines–unable to comply immediately with the AAIB recommendation because their own regulations require an operational ELT. In its statement, however, the FAA said it would communicate its intentions to aviation safety authorities in other countries.

“Japan Airlines has conducted self-inspection for these ELTs on its 787s currently in operation,” said JAL in response to a written query from AIN. “Should Japanese regulations provide any introductions to the airlines in the coming days, JAL will take appropriate action in response to the further factual details.”



How strange that Japan requires a working ELT............................

If the problem is in the Li-Mn batteries, [Which is extremely unlikely] turning the ELT off will not solve that problem.

Overall, the danger from not having a working ELT on board is many orders of magnitude worse than the danger of a short-circuit causing a fire.

All electronic devices must be fuse-protected, and all critical devices need a 'Fuse blown' indicator on the PFD of every airplane.