On July 12 a parked Ethiopian Airlines’ 787 was attended by several emergehcy vehicles at London Heathrow when a fire broke out. The blaze caused extensive damage to the rear of the plane’s fuselage. No one was aboard the plane and there were no injuries.

Investigators have found that the fire coincided with the emergency locator transmitter, which is powered by a lithium-manganese dioxide battery. This system operates independently of the plane’s power system. It is also different to the system on the plane that caught fire in Boston earlier this year. The British investigators have found damage to the battery’s cells but are not yet certain whether the battery caused the problem or a short-circuit ignited the battery. There are approximately 6,000 emergency locators with these type of batteries across the globe. None have previously caught on fire.

As a result of the Boston fire, Boeing added more insulation between the power system battery’s cells, surrounded the battery with a metal box to prevent spread of any potential fire and installed a tube to carry flammable materials off the plane if there were a fire. There has still not been any identified reason as to why that battery caught fire.

The Air Accidents Investigation Branch has called for the U.S. Federal Aviation Administration and manufacturer Honeywell International to research changing the power source for the locators.
They suggested making the locator’s power source inert until the problem is investigated and to review the installation of lithium-powered locators in other planes

Boeing also supported the recommendations as “reasonable precautionary measures,”. They said: “We are confident the 787 is safe, and we stand behind its overall integrity,”