A different kind of battery issue may to be blame for the fire near the tail section of the Ethopian Airlines Boeing 787 at London’s Heathrow Airport last week.
The British equivalent of the National Transportation Safety Board is recommending the Emergency Locator Transmitter (ELT) system built into the Dreamliners be temporarily removed or disabled and a safety review of other aircraft be conducted.
On Saturday, the FAA ordered the inspection of wire damage or pinching as it relates to ELTs on Boeing's worldwide fleet of 787s.
In a statement, Boeing spokesman Marc Birtel called the AAIB recommendations “reasonable precautionary measures to take as the investigation proceeds.”
“The investigation continues, and it’s premature to jump to conclusions,” Birtel said.
Honeywell, the manufacturer of the ELT, said in a statement sent to ABC7 News, “Temporarily addressing the ELTs on Boeing 787s as a precautionary measure is prudent.”
No one was on the Ethiopian Airlines plane when it caught fire on July 12.
The safety recommendations come in a Special Bulletin issued Thursday by the UK Air Accidents Investigation Branch, which has been leading the investigation to the fire that has include representatives from NTSB and FAA.
“There are no other aircraft systems in this vicinity which, with the aircraft unpowered, contain stored energy capable of initiating a fire in the area of the heat damage,” the Special Bulletin says.
The Bulletin notes that Honeywell has produced roughly 6,000 of the devices and this incident “has been the only significant thermal event.”
The transmitter is designed to work entirely independently of the rest of the aircraft and is activated in the event of a crash to help searchers locate a downed plane. It is powered by a Lithium-Manganese Dioxide battery which is different than the more volitale Lithium-Ion batteries used to the power the revolutionary Boeing airliner.
According to investigators, it remains unclear if the fire began inside the ELT or if an external short circuit ignited the battery. The fire caused extensive heat damage to the upper portion of the rear fuselage.
“We are confident the 787 is safe and we stand behind its overall integrity,” Boeing’s Birtel wrote.
All 787 airliners in commercial service were grounded for three and half months earlier this year after a battery caught fire inside the Auxilary Power unit of a Japan Airlines 787 as it was parked at the gate at Boston’s Logan airport and a second battery issue on board an ANA owned 787 in Japan.
On Thursday, a JAL 787 returned to Boston Logan airport with a mechanical issue, reportedly a possible issue with a fuel pump. Relatively minor issues, often referred to as ‘teething,’ are common with new airframes.
The Dreamliner has is Chicago based Boeing’s newest, most advanced and fuel-efficient jetliner with more than 500 orders on the books. United Airlines is the only United States based carrier operating the innovative jet.
The FAA says it will order inspections of the Emergency Locator Transmitters in the coming days, saying in a statement provided to ABC7 News, "These inspections would ask operators to inspect for proper wire routing and any signs of wire damage or pinching, as well as inspect the battery compartment for unusual signs of heating or moisture.
The order for inspection will come in the form of an Airworthiness Directive to "make these inspections mandatory."
The FAA will spend the weekend alerting aviation safety regulators in other countries of its pending action.