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Lyman,
Unless you are looking at the battery from behind |
No, as it is shown on page 8
Caveat. If you consider the reference for NTSB page seven and nine are "plan view" then by reference ONLY, page seven can be construed as accurate. Stand alone, page seven is reversed. "elevation" :ok: |
787 battery approval should be reconsidered, top accident investigator says | Fox News
National Transportation Safety Board Chairman Deborah Hersman said the board's investigation of last month's battery fire in a Japan Airlines 787 "Dreamliner" while it was parked in Boston shows the fire started with multiple short-circuits in one of the battery's eight cells. That created an uncontrolled chemical reaction known as "thermal runaway" and spread to the rest of the cells, she said. That's at odds with what Boeing told the Federal Aviation Administration when the agency was working to certify the innovative aircraft for flight, Hersman said. The manufacturer asserted its testing showed that any short circuiting could be contained within a single cell, preventing thermal runaway and fire, she said. Boeing's testing also showed the batteries were likely to cause smoke in only 1 in 10 million flight hours, she said. But the Boston fire was followed nine days later by a smoking battery in an All Nippon Airways plane that made an emergency landing in Japan. The 787, Boeing's newest and most technologically advanced plane, has recorded less than 100,000 flight hours, Hersman noted. |
llagonne66:
If you read between the lines, NTSB appears to take a tough stance and FAA looks on the defensive as they have certified the A/C while apparently overlooking something ... FAA did that as well ?. But, who watches the watchers ? :confused: |
Lyman:
Correction to NTSB images. If we are going to follow the narrative with these visual aides, we age going to get lost. Which cell #6 ran away first? :confused: I hope this is just a problem with the people doing the presentation artwork and not NTSB's evidence. |
:( guys, just a post from left field.....i'm not that knowledgeable about aircraft design, but just from common sense and experience, why would you place any substance, gizmo, etc. that could possibly (and, according to Murphy's Law, will at some point) become toxic anywhere near the pilots of a commercial aircraft, who are the only ones on board with a chance of saving the situation. i don't know what the airbus folks are doing with the a350 in the works, but i'd love a look at it.
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Test flights to go ahead
BBC News - Boeing gets permission for Dreamliner test flights |
ANA 787 smoke
Hi,
The main battery smoke left from the plane in two points: The one underneath was what? http://oi49.tinypic.com/vcqbd3.jpg |
EEngr and cwatters:
"The 8 sub batteries are balanced but the 6 cells in parallel in each don't appear to be. However that's not usually a problem because cells in parallel will tend to auto balance..." They tend to auto balance as long as charge/discharge currents are not too high. If for some reason a sudden current spike occurs, then the paralleled cells can start to misbehave due to inrush/outrush currents being momentarily too high for the auto balancing mode to work fine. For normal operations this may well be not an issue at all, but if an abnormal situation occurrs and current spikes are appearing I would prefer not to have to rely on auto balancing of Li-Ion (and LiPo for that matter) cells. |
edit : Preseance to WanganuiLad : I missed his post with BBC message...sorry
US clears Boeing to start 787 test flights - Transport - ArabianBusiness.com "US clears Boeing to start 787 test flights By Reuters Friday, 8 February 2013 10:46 AM : US agencies cleared Boeing Co to restart test flights of its grounded 787 Dreamliner in order to get more data on potentially faulty batteries, but they also demanded a closer look at how the batteries were approved, which may delay resuming delivery of Boeing's newest aircraft. The 50 Dreamliners in service were grounded worldwide on January 16, after a series of battery incidents, including a fire on board a parked 787 in Boston and an in-flight problem on another plane in Japan. The groundings have cost airlines tens of millions of dollars, with no end in sight." |
Originally Posted by WanganuiLad
(Post 7682500)
It really is rather a specialist subject, the operation of some test flights, but I suppose everyone at PR will now be working 24 hours a day hammering their media contacts to ensure an unending diet of "test flight takes off successfully", "test flight lands successfully", and such like. |
which may delay resuming delivery of Boeing's newest aircraft |
I wonder how many test flights will need to take place before an incident of any sort happens, or, conversely, when do you stop if no events happen.
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Test flights are generally conducted to obtain data, not to provoke 'incidents'.
All possible precautions are usually taken to minimize the risk of potentially uncontrollable situations. |
If I am Boeing, I am thrilled that this type is airborne once more, for any reason.
It is a beginning to a critical process of re acceptance, as well as re certified.... Prolonged perception of "cannot fly" by the public is having an effect on other than airworthiness. To deny that is silly. And to frame the test flights as strictly single purpose is a bit narrow, imho. For three years past its due date, the company worked feverishly to get it airborne... Call it cultural corporate memory... |
Prolonged perception of "cannot fly" by the public is having an effect on other than airworthiness. Anyways .. passengers continued to happily boarding the DC-10 |
Not me. The only time I saw a DC-10 launch I saw #2 compressor Stall at rotate, the flame was a hundred feet long, my girlfriend was on board.
Mexicana. I have never flown on a Douglas aircraft, save the -9. Boeing was shrill, offensive, and played the corporate lunatic when FAA finally grounded the DREAM. They were replacing batteries, and they may have thought they had solved "the problem". |
Test flights are generally conducted to obtain data, not to provoke 'incidents'. All possible precautions are usually taken to minimize the risk of potentially uncontrollable situations. Without such an event they will have no more knowledge than they have now, hence my comment on how long do they keep looking for something. What would be interesting to know is what instrumentation has been added to the battery pack and charging system to record the parameters. |
my use of the word 'incident' to mean an individual occurrence or event out side of the normal operating parameters That would be an open-ended project that could take months of 'incident-free' flying before seeing something out of the ordinary. As Hazel says, this may be no more than an exercise in real-time data collection. Remember Boeing should have 100-150 batteries worth of data from the 'swap-outs' to go by, so this operation must be looking for something over and above what they already have. I'm not sure what extra gear would need to be hooked up to the system over and above what is already there to 'feed' the algorithm. And remember, any further monitoring of things like sub-cell temperatures, voltages and currents would be fairly invasive of the actual battery itself to the point where you would be effectively looking at a different system. :( |
A possibility might be that the Aft E/E bay has been made accessible in flight by removal of cabin floor decking, for real time minute observations to ascertain how better to make the system more compatible with the LithiumIon FARs.
It would be naive to think that Boeing is playing a boy scout role in trying to eliminate the issue. Or even solve the problem, beyond a minimal, and lobbied for, result that lifts the order to park. 'Best practice' is about getting back in the air. Not entirely, but when the self certifier and lead commercial interest in the investigation is not, cannot be, objective..... The certifying criteria for this technology is cobbled together by the manufacturer, that is a known. The recent waiver of the FAR that prohibited LithIon batteries as cargo is case in point....How did BOEING ship replacement LIBs prior to January 7? RAILROAD? How did that FRP work, exactly? Hersman is the one to listen to, FAA and Boeing? Not so much... |
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