The fire aboard an Ethiopian Airlines 787 in London last week has been traced to the battery of an emergency locator transmitter (PDF), and British regulators are recommending that airlines disable the device. In a special bulletin yesterday, the U.K. Air Accidents Investigation Branch also urged that the U.S. Federal Aviation Administration review the locator beacon in other airplane models and order a safety directive if needed. An FAA spokesman said the agency is reviewing those recommendations.
The beacon, powered by lithium-manganese dioxide, is built by Honeywell International (HON) and located in the 787′s ceiling, near the back of the plane. “Had this event occurred in flight it could pose a significant safety concern and raise challenges for the cabin crew in tackling the resulting fire,” the U.K. aviation agency said.
Airlines are now inspecting the beacons, with at least one carrier, Thomson Airways (TT/:LN), having decided to remove the device. The only U.S. operator with 787s, United Airlines (UAL), performed “visual checks” on the beacons in its six planes and said it would work with federal regulators and Boeing (BA) “to ensure we take the appropriate action,” spokeswoman Christen David said in an e-mail.
Whatever action that might be, it’s likely that FAA officials will decide what to do soon, given the regulatory uncertainty the British have unleashed. In the mean time, the fire aboard the parked and empty Ethiopian Airlines plane leads to plenty of other questions. Below, our effort to dispel the some of the uncertainty around the beacon.
Is this emergency transmitter only on the new Boeing 787s?
No. Honeywell has sold more than 6,000 of the beacons (PDF), which weigh about 6 pounds, including the battery. The design dates to the late 1990s, although similar locator technologies were first introduced decades earlier.
So why hasn’t this issue shown up before?
Good question. The AAIB statement (PDF) said that the July 12 fire at Heathrow Airport was the only “significant thermal event” seen with the beacon. A Honeywell spokesman declined to comment on the transmitter’s service history, citing the regulatory inquiries.
Is this thing dangerous?
That’s what regulators want to determine. Lithium-based batteries have long been suspected of being risky in aviation—including the case of a UPS cargo plane crash in 2010—given the heat they generate as part of the chemical reactions needed to produce power. A second type of lithium battery led to the three-month grounding of the 787 fleet in January and prompted Boeing (BA) to redesign the system for use on the airplane.
Not to be morbid, but what if my flight crashes? A beacon might be needed, right?
U.S. regulators don’t require it, although some countries do. Many, many airlines choose to install them. The big carriers fly their long-haul fleets in some of the most remote spots on earth, such as the North Pole and across the Pacific, so there’s plenty of reason airlines, insurers, and passengers want locator beacons aboard these very expensive airplanes. (The horrific 2009 crash of an Air France flight into the Atlantic could be Exhibit A for a beacon’s utility.) However, given the tracking that airlines do for every flight—some with control centers that rival NASA—not to mention all the commercial satellites constantly scouring the globe, it’s easy to argue that a downed flight will be found.
Is Honeywell the only beacon supplier?
Not at all, and the company has taken pains to point out that it believes the safety of rivals’ beacons should also be reviewed.
Is there a connection between the 787′s electrical system and the beacon?
No, the beacon powers itself. But the lack of other incidents before its use on the 787 is probably something that Honeywell and Boeing engineers want to understand.