787 battery fix gets thumbs up from aviation experts
Independent experts say Boeing’s proposed 787 Dreamliner fix — a heavy stainless steel box that will contain any heat, flames or flammable vapors from the lithium ion battery — is a solid solution.
Seattle Times aerospace reporter
This extract from a Boeing video shows a severe test of the proposed 787 battery containment enclosure. Propane gas ignited inside the box explodes. The 1/8th-inch thick steel walls bulge out but hold fast.
Watch the full Boeing video showing the battery fix now being tested.
Independent experts view the fail-safe part of Boeing’s proposed 787 Dreamliner fix — a heavy stainless steel box that will contain any heat, flames or flammable vapors from the lithium ion battery — as a solid solution.
This part of the fix, because it’s focused on containment rather than prevention, has drawn some skepticism.
But to John Goglia, a former member of the National Transportation Safety Board and now an outspoken critic of the FAA and Boeing, it’s this box that makes Boeing’s solution acceptable.
“No matter what happens to the battery now, it won’t be a problem because it’s contained,” Goglia said. “It’ll probably satisfy the FAA to get the airplane back in the sky.”
Certification tests will continue through the weekend on Boeing’s fix, designed to avoid future incidents like the two that grounded the jets — a battery fire on the ground and a smoldering battery in flight.
Two flight tests are expected next week, with an initial flight as early as Monday to give the test equipment a run-through, and then a certification test flight to follow a few days later.
But the flight is relatively run-of-the-mill, merely gathering data from the battery during normal operation.
Other tests are more severe, including one lab test that involves igniting propane inside the containment box, causing an explosion that increases the pressure to three times what could be expected in the worst-case scenario.
Boeing has already done a successful run-through of this test. A video shows the 1/8th-inch-thick steel walls of the box bulge out in slow motion. But they hold fast and regain their shape.
However disconcerting it may be to the average airline passenger to imagine anything resembling that happening under the passenger floor in flight, top engineer Peter Janicki said it can assure safety.
Janicki is the founder and president of Boeing supplier and high-end aerospace toolmaker Janicki Industries of Sedro-Woolley. He said building an enclosure to contain even the worst-case battery overheating or fire event is not that difficult an engineering problem and can be accomplished with virtual certainty.
“It’s easy to calculate the amount of energy in the battery and it’s easy to calculate the amount of energy the box can absorb,” said Janicki. “Mathematically, to know whether it will work is a fairly precise science.”
An aviation-safety engineer, who asked for anonymity because he spoke without the approval of his employer (not Boeing), agreed that the proposed battery fix “looks pretty good.”
Though he’s critical of how the FAA appears to have rubber-stamped Boeing’s original battery design, he said the revised battery system should be approved and certified to fly.
The FAA “agreed to the test plan, so if Boeing passes the test plan, I don’t see how they couldn’t approve a return to service,” the safety engineer said.
He pointed out that jet airliners contain flight-critical devices with much higher energy than the batteries, such as the engines hanging off the fuel-filled wings, and that these have been engineered to be safe and reliable, even though they very occasionally catch fire.
“The idea of controlling a fire on an airplane is nothing new,” the safety engineer said.
A senior Boeing electrical engineer, who cannot be identified because the company won’t approve, also said he’s satisfied that the enclosure box will “take care of the battery.”
“It isn’t glamorous or elegant, but I think it’ll fix it,” he said.
He said the fix, which adds 150 pounds to the weight of the airplane — more than doubling the weight of the two main batteries involved — completely negates the weight savings that had been expected from using lithium ion instead of nickel cadmium batteries.
“Sometimes, when you run into unexpected problems, it evolves into the total opposite of what you wanted,” the Boeing engineer said.
As the fix is tested, Boeing anticipates that the FAA will lift the grounding in April with the backlog of jets having the fix retrofitted in the months that follow.
As a result, the company is telling its supply chain to stick to the 787 production plan laid out before the battery problems emerged in January.
An executive at a Boeing supplier, who asked not to be identified, said, “they certainly aren’t slowing down.”
He said his company is gearing up for the introduction of the 787-9 to the assembly line this summer and the rate increase to 10 Dreamliners per month by year end.
“Everyone is still moving forward,” the executive said.
Peter Janicki said his firm, which has multiple 787 contracts, is seeing the same, with 787 momentum unaffected by the grounding that has already lasted nearly 10 weeks.
“There’s no slowdown,” Janicki said. “Every indication is that (Boeing) sees this as a glitch.”
Dominic Gates: (206) 464-2963 or firstname.lastname@example.org