backtop


Print 19 comment(s) - last by JimboK29.. on Mar 19 at 1:21 PM

New safety upgrades could make this possible

Source: Boeing





Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: stating the obvious
By Dorkyman on 3/15/2013 1:50:53 PM , Rating: 2
Not fair.

You don't spend money to fix a "problem" if there is no problem to be fixed.

Yeah, NOW we can see that there are issues, but at the time it seemed all that had to be done was to make sure the batteries were not overcharged and they would be okay (okay, I'm simplifying a bit but that's the main idea).

How is it that an intersection often doesn't get a traffic signal until there's an accident there? Because there are millions of intersections and it would be financially impossible to put signal at every one of them.

My own suspicion is that Yuasa made some substandard cells but Boeing has probably wisely decided to design an environment where even a faulty battery can be tolerated.


RE: stating the obvious
By Voldenuit on 3/15/2013 2:31:22 PM , Rating: 2
quote:
How is it that an intersection often doesn't get a traffic signal until there's an accident there? Because there are millions of intersections and it would be financially impossible to put signal at every one of them.


By this analogy, the original 787 battery design, which had:
1. Known unstable chemistry
2. Potentially unsafe cell configuration
3. Inadequate fire and smoke containment and venting

would be analagous to building an intersection in a heavily trafficked region with:
1. No stop signs
2. No lighting
3. Runoff area is a ditch filled with stakes and man-eating crocodiles

Essentially, they designed an unproven and potentially unsafe configuration without a contingency plan in place other than "don't catch fire". I know it's tempting to be an 'internet battery expert' when commenting about the 787 woes, and that hindsight is always 20-20, but I can't even begin to see where due dilligence was done on the 787 battery in the first place.


RE: stating the obvious
By Solandri on 3/15/2013 4:17:31 PM , Rating: 3
quote:
By this analogy, the original 787 battery design, which had:
3. Inadequate fire and smoke containment and venting

To be fair, if you look at pics of the battery which caught fire, the battery is destroyed but the external case appears pristine. So apparently it had adequate fire and smoke containment (not so sure about the venting). In that respect there was no danger to the plane.

The problem was the batteries weren't supposed to catch fire in the first place, but they had two incidents within the first few months of service. Which led to a reassessment of the fire risk, forcing a redesign which assumed a higher frequency of fire. So now they're adding things like isolating different cells from each other so a fire doesn't spread as easily between cells.

Basically they've gone from "in the highly unlikely event of a fire, it will be contained," to "in the event of a fire, its effects will be mitigated by this, this, and this."


RE: stating the obvious
By GulWestfale on 3/15/2013 6:42:02 PM , Rating: 2
quote:
As for the battery itself, two kinds of insulation were added: an electrical insulator and a thermal insulator, which will wrap around/below each battery cell to keep them away from each other and the battery case.


wow... really... one would think that this would have been in place from the get-go, weight savings or not. safety should come first, as should extensive field testing.


RE: stating the obvious
By Voldenuit on 3/15/2013 8:09:43 PM , Rating: 2
quote:
To be fair, if you look at pics of the battery which caught fire, the battery is destroyed but the external case appears pristine. So apparently it had adequate fire and smoke containment (not so sure about the venting). In that respect there was no danger to the plane.


The smoke vented into the cabin in the Boston incidents as well as the Japanese one, which was a definite safety issue. You are correct that the fires did not damage any surrounding structures AFAIK.


RE: stating the obvious
By Fireshade on 3/19/2013 7:09:57 AM , Rating: 2
quote:
The problem was the batteries weren't supposed to catch fire in the first place, but they had two incidents within the first few months of service. Which led to a reassessment of the fire risk, forcing a redesign which assumed a higher frequency of fire. So now they're adding things like isolating different cells from each other so a fire doesn't spread as easily between cells.

Rightly put.
From other technological articles on the Dreamliner solution, you can tell that Boeing's fix only addresses the symptoms. They have not yet found and solved the problem itself, i.e. they still don't know why the batteries can become instable/overheated.

Apparently Boeing and its partners are comfortable with these kind of fixes, when money is at stake. Which is really bad, because it means that money is more important than intrinsically safe design.


"This is about the Internet.  Everything on the Internet is encrypted. This is not a BlackBerry-only issue. If they can't deal with the Internet, they should shut it off." -- RIM co-CEO Michael Lazaridis










botimage
Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki