Monday, July 22, 2013

The Seattle PI, ELT Fire Primer

The Primer Article : Ethiopian 787 Fire Sparks Question: Is Lithium Ion Ready to Fly?

My own introduction:  Good thoughts flow from this piece by Christine Negroni. It lays out a big picture of what Boeing and the investigators are grappling with and constructs those possibilities not included in press releases or news articles. I humbly recommend reading the complete feature as it may add to your own archival links of Boeing's journey to the flight of the 787.

Christine Negroni
" Is it a coincidence that right after Boeing announced it had solved its first flammable battery problem it now may have another?  It is worth considering if the Dreamliner's unique features have a role to play. Today Reuters reportedthat humidity and wiring are getting the attention of investigators in the U.K.. But I'm also pretty darn sure that the nature of the carbon fiber fuselage may also be under scrutiny."

"Advanced batteries with very different chemistries seem to have a marked propensity to misbehave when installed in Boeing 787 Dreamliners," Larsen told me when I called to get his take on the latest installment in the ongoing Dreamliner saga. Larsen was one of many people I interviewed while working on previous stories about the two fire events on Japanese-operated planes. I paid close attention. I was pretty sure I understood that the cobalt oxide flavored battery selected by Boeing for back up power on the Dreamliner was the bad-boy, super-scary formulation, picked because it was fast charging and packed a punch. But more volatile than iron phosphate and the ELT's manganese oxide."

To some extent my understanding was correct. But darned if Larsen didn't tell me that the ELT's non-rechargeable batteries can also fail with catastrophic consequences. The only difference is that non rechargeable batteries are less likely to do so than the rechargable carbon oxide lithium ion ones that caused the Dreamliner's problems this past winter.
Stay with me here while I explain that the issue with all of these batteries is that during their lifetime they develop teensy-weensy internal structures called dendrites. That's a bad thing because if they get to close to each other the dendrites will arc. They will release a super hot 4,000 to 6,000 degree electrical spark. By way of comparison, the surface of the sun is about 10,000 degrees.
Okay so the blasted thing is hot, get it? That means the heat is sufficient to breaks down the chemical components in the battery and feed on this as fuel along with and anything else in its way all at a temperature that can melt titanium and - apparently ignite a carbon fiber composite airplane fuselage.
This is a shocking scenario to imagine on an airplane in flight. Lest you jump to the conclusion - as I did at first - that Larsen is some too-far-out-there voice of doom, take another look at the damage on the battery in the Japan Airlines Dreamliner that went bad in Boston."

Author Archives: Christine Negroni

About Christine Negroni

My life as an aviation writer began with the crash of TWA Flight 800 in 1996. I covered it for CNN and my book about it, Deadly Departure was published in 2000. This piqued my interest in all kinds of flying and the mix of human, mechanical, technological and scientific factors that make it possible. Safety in particular intrigued me so I became an investigator for a New York aviation law firm. I am not a pilot or an engineer. My outsider status prompted the FAA to include me on a committee creating new rules for aging airplane wiring. I brought a non-technical perspective to the task. So some years have passed and I’ve “kicked the tin” on a few airplanes as the expression goes. Now write about aviation for The New York Times and I lecture at colleges and conferences. I often appear on those disaster documentaries that run on Discovery or History or the Learning Channel. I no longer claim to be an outsider. Aviation has its warts. But no other industry has learned and incorporated so much knowledge about human behavior into its operations. My unique vantage point these past 15 years gives me just the right altitude from which to write Flying Lessons.