Crossed or crushed wires are now the leading cause of that fire in an Ethiopian Airlines Boeing 787 two weeks ago.
It's looking like human error, and not a design flaw, is being considered as the reason why the Emergency Locator Transmitter caught fire and burned the 787 as it sat at the terminal at Heathrow Airport in London.
The Seattle Times reports the investigation has found that the wires connecting the battery to the transmitter were trapped and pinched by the cover by an improper installation, and that likely caused a short-circuit that sparked the fire.
The FAA will put out a directive on Friday requiring 787 carriers to inspect the ELT's for pinched wires.
This potentially puts the blame for the fire on the ELT manufacturer, Honeywell, which might have replaced the batteries on the device before delivery.
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