Investigators are looking into the cause of a blaze that ignited on an empty Boeing (NYSE:BA) 787 Dreamliner parked at London’s Heathrow Airport on July 12. The United Kingdom’s Air Accidents Investigation Branch, or AAIB, found last week that a malfunction of the Honeywell-manufactured (NYSE:HON) emergency locator transmitter, or ELT, started the fire aboard the Ethiopian Airlines-operated plane.
However, the investigation has not yet been concluded. As Bloomberg reported Saturday, the probe is now focused on whether crushed wiring in the 787’s emergency beacon bore any responsibility for the incident. Sources told the publication that the AAIB and U.S. regulators are also continuing to examine a variety of possible causes for the fire.
On Saturday, two days after the AAIB released its special bulletin with safety recommendations for Boeing, the U.S. Federal Aviation Administration announced that it was working with Boeing to develop instructions for airline operators to inspect ELTs on all 787s.
“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 press release said. An Airworthiness Directive will be released in the near future, which will make the inspections mandatory, the release added.
The battery-powered ELTs are self-contained in aluminum alloy casing and are not integral to flight operations, but the transmitters are included on the 787’s minimum equipment list, according to the FAA’s website.
But the FAA’s actions fell short of what the AAIB suggested its bulletin. First, the British regulatory agency recommended that the FAA should “initiate action for making inert” the ELT system in all 787 planes until “appropriate airworthiness” could be determined, and second, the agency said the FAA should conduct a safety review of lithium-powered ELT systems in all other types of aircraft. Instead, the directive proposed by the FAA would apply to just the six Dreamliners operated by United Continental Holdings (NYSE:UAL), because no other United States-based carriers operate the plane.
“We received the recommendation from the AAIB and are working closely with Boeing and the FAA to ensure we take the appropriate action,” Christen David, a spokeswoman for United Continental, told Bloomberg via telephone before the FAA’s announcement. “We have already performed visual checks on the emergency locator transmitters with no findings.”
Foreign aviation regulators typically make similar recommendations: in January, when the FAA grounded the 787 following two meltdowns in the plane’s lithium-ion batteries, Japan followed suit. The FAA was expected to inform aviation safety regulators in other countries regarding its plans over this past weekend.
For operators of the more than 68 Dreamliners in service, the problem has been how to deal with fire’s safety repercussions. Japan’s Transport Ministry is allowing all beacons to be removed from Dreamliners, Megumi Tezuka, a spokeswoman for ANA Holdings (ALNPY.PK), which has the largest 787 fleet, told Bloomberg in an email on Friday. Poland’s LOT operator said it examined the device and that the transmitters are “fine,” while the U.K. carrier Thomson Airways removed the beacons, the publication reported.
As for Boeing, its stock has largely recovered from the post-fire dip, which saw investors bid down shares by 4.7 percent, as the incident was reminiscent of the battery problems the 787 experienced earlier in the year.
Since two battery meltdowns forced regulators in the United States and Japan to ground the Dreamliner fleet in January for three-and-a-half months, Boeing has fought to rebuild trust in the wide-body plane. And for the most part, it has: the company’s stock has gained almost 40 percent this year and it is just slightly below its 52-week high of $108.15.
In response to the ELT problem, Boeing has “provided instructions to customers giving them the required information to meet their regulatory guidelines,” Marc Birtel, a Boeing spokesman told Bloomberg. “This includes either the inspection or removal of the ELT on affected airplanes, as dictated by local operational requirements.”
Follow Meghan on Twitter @MFoley_WSCS