PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 8th Mar 2013, 01:05
  #854 (permalink)  
Chris Scott
 
Join Date: Jan 2008
Location: Blighty (Nth. Downs)
Age: 73
Posts: 2,076
NTSB Interim Factual Report

Been out all evening since downloading it, but now see some have been struggling to locate it. Seems to be slightly different from the one posted above by archae86, but If his or others don't work, readers might like to try this one for the
NTSB Docket Management System:

Document 7 Airports/ARFF 16 - Attachment 3: BOS ARFF Incident Report Filing Date February 12, 2013 5 page(s) of Image (PDF or TIFF) 0 Photos

I commented earlier:
"So the failure occurred about 16 mins after the recharge cycle had begun. Must admit I had expected a longer time-frame. I wonder what the temperature of the battery was before and after APU start."

Quote from Lyman:
"Didn't APU start off one of the donks?"

Yes and (maybe) no. I'm not sure our experts in PPRuNe know enough about the system to establish what proportion of the APU starter-generator load is taken by the main electrical system (when available, as in this case), and how much (if any) is taken by the APU battery. On my last a/c type, the battery is used to supplement the main-system TRs in supplying the 700-1000 amps initial load. However, that system architecture may not be necessary or applicable on the B787.

If the APU battery took no significant part in the APU start, it seems an odd coincidence that the failure should have taken place so soon after APU start, at the end of a 12-hour flight.

To indulge in speculation, the only other possible triggers that spring to mind might be the changes in pressure associated with the recent descent and landing, or the very recent temperature changes caused by the opening of the rear cargo doors adjacent to the Aft E&E Bay. Does anyone know the temp at BOS?

PS
The link I posted above doesn't work for me right now, and neither does the manual one posted by archae86. Part of the problem may be at the NTSB end, I guess.

Last edited by Chris Scott; 8th Mar 2013 at 01:24. Reason: PS added.
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