Passengers had just gotten off the Japan Airlines jet after arrival from Tokyo when a mechanic performing a post-flight walk-around noticed smoke inside the cabin and pouring out of a rear underbelly cargo door. According to an airport spokesperson, responding firefighters extinguished flames confined to the plane?s aft electronics bay. Shortly after the fire was put out, one of the plane?s batteries exploded, injuring one fireman. According to a Japan Airlines statement and reports from Boston firefighters at the scene, a battery started the fire, though it was not clear whether it was the same one that exploded.
The bad news continued on Tuesday. Another Japan Airlines 787 at Boston's Logan Airport aborted a scheduled takeoff after a fuel leak appeared. And the Wall Street Journal is reporting that United Airlines, inspecting its own new 787s in response to the fire, found "improperly installed wiring" near the after electronics bay.
The aft electronics bay, which stretches along the underside of the fuselage just behind the Dreamliner?s wings, is one of the 787?s vital nerve centers. It?s filled with generators, batteries, and wiring that allow the new Boeing jet to rely upon electrical power more than any aircraft ever built. For example, where cabin ventilation systems traditionally make use of thrust-draining "bleed air" piped in from the plane?s engines, the 787?s air conditioning runs on electrical power provided by generators. To save weight, many of the 787?s control surfaces are moved by electronic servos and sensors rather than heavier hydraulics.
Yes, the 787 has redundant parts to back up the electrical systems for critical components. But the 787?s electrical problems, including a few from before this week?s incident, have some aviation experts worried, in part because some of the technology has never been used before.
Extended Operations
"While it is too early to determine the cause or seriousness of this incident, the NTSB [National Transportation Safety Board] chose to review it," airline analyst Robert Mann of R.W. Mann & Company tells Popular Mechanics. Mann says he suspects the government is going to review this one closely because "this aircraft/engine combination is being delivered with FAA-approved 330-minute ETOPS, incorporating Special Conditions for the use of lithium-ion batteries in critical systems."
To put that in plain English: ETOPS (Extended Operations) is a set of FAA safety and maintenance rules that specify the maximum distance in minutes that a particular type of aircraft may fly from a diversion airport?the place where it would land in case of emergency. The FAA has certified the 787 for its highest ETOPS rating, ETOPS 330, meaning operators are allowed to fly it on routes that may take it up to 5-1/2 hours from the nearest airport where the plane could land safely.
That status is crucial for a plane like the 787 that?s designed to fly international routes. Transpolar routes, for example, can cut flight time by hours between North America and Asia but can take an aircraft far from the nearest airport. But it also makes potential electrical problems scarier. "An uncontainable lithium battery fire under these circumstances would be problematic," Mann says, perhaps putting it lightly.
That?s where the "Special Conditions" that Mann mentioned come in. Lithium-ion batteries make the 787?s heavy reliance on electronics possible, but they have never been used so extensively in an aircraft. Because of special concerns regarding their stability and flammability, the FAA closely examined their use on the 787 and issued a set of conditions that Boeing had to meet, which include regulations for maintaining strict charge levels and temperatures, and preventing heat and gases from escaping and damaging other parts of the plane. The FAA issued similar conditions for Airbus's A380 super jumbo, which also uses lithium-ion batteries, but to a lesser extent.
Past Incidents
Lithium-ion batteries have caused in-flight problems even when carried as cargo. In 2010, a UPS Boeing 747 crashed in Dubai when its large shipment of lithium-ion batteries burst into flames. The FAA subsequently issued special rules for airlines about the risks of lithium batteries, including new regulations for passengers carrying camera batteries.
Equally concerning are the prior problems with the 787?s aft electronics bay. In early December 2012, a United Airlines 787 flying from Houston to Newark made an emergency landing in New Orleans after the pilots received warnings of a failed electrical generator. Fearing a possible fire in the bay, the crew instructed the firefighters who met them on the ground after landing to look for smoke or melting around behind the wings. There was no fire, and the plane returned to service after Boeing traced the problem to a faulty electrical distribution panel that gave false warnings. Still, the crew had ample reason to react with such caution. The mishap came just 10 days after a similar situation on another United 787, and a few days after yet another electrical panel issue on a Qatar Airways 787. Boeing replaced the panels on several other 787s after these incidents.
In a more serious case, a fire did break out in the electronics bay of a Dreamliner during a 2010 Boeing test flight, forcing an emergency landing in Laredo, Texas. Boeing blamed that fire on debris in the electronics bay and said it would make some minor design changes to prevent further problems.
While it is not unusual for a brand-new type of aircraft to encounter teething problems as it enters the world?s commercial fleet, 787 customers were already bristling that their planes were being delivered 3-1/2 years late. Some have demanded billions from Boeing in compensation for the delays, and others have cancelled their orders outright. Boeing has 800 more orders for the 787 on the books, worth about $200 billion, so you can bet the aerospace giant is rushing to try to eliminate these embarrassing incidents.
Matt Molnar is the editor-in-chief of NYCAviation.com.
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