PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 18th Feb 2013, 16:42
  #719 (permalink)  
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,123

Flight Path

“The expectation in aviation is to never experience a fire on board an aircraft,” the NTSB chairwoman declared, her voice deliberate but dispassionate."
A little clarity from a public official. She is doing a good job under difficult circumstances. Instead of learning from her example, The Director of the Department of Transportation, Ray LaHood, simply resigned. FAA spokesperson Huerta is likewise performing spin duty.


a) Separate each LVP-65 ideally in individual chambers. (battery volume would be aprox. 30 ~ 40 % more)
That is the current design. Each battery (erroneously called "cell") is contained in its own plastic box. Between these batteries, is a layered steel, insulate sandwich. A new design would be Steel pigeon holes, or "egg crate" enclosures.

Does nothing to prevent a thermal runaway. NTSB have concluded the JAL failure began with a single battery, #3. So any egg crate mod merely isolates the batteries from each other. Still possible is the prohibited "fire" to which Ms. Hersman refers.....

b) Monitor each LVP-65 temperature (if not yet made)
A noble attempt to.....what? Try to prevent fire? Once the temp is thresholded, the Batteries are shut down, the back up system is off line, and the purpose of the system competes with its "shutdown" feature".

c) Tweak software algorithms
To better "balance" charging? algorithms only peripherally "control" temps., and cannot mitigate exothermic reactions, the source of "runaway".

d) Improve mitigation means. (better battery case, better venting, safer batteries location, etc.)
All this does is underscore how badly Thales and BOEING designed the system in the first place.

If Director Hersman is accurate regarding her interpretation of "fire", the word "mitigation" is in direct contradiction. Fire is PREVENTED, not MITIGATED....

A new system for Aviation: "INFLIGHT FIRE MANAGEMENT SYSTEM"

IFMS.... really?

edit. RR, just a suggestion re: the "short" at the connector strap. Look closely and see if you are not tempted to look at the deficit as "cut" by a gas jet, instead of a simple "fusion" due to heat of current. The battery case is aligned with the triangular "cut", and the metal has characteristics of a torch cut, complete with "beads" of molten metal along the very linear edges..... Is it completely severed?

Last edited by Lyman; 18th Feb 2013 at 17:12.
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