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787 Batteries and Chargers - Part 2

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787 Batteries and Chargers - Part 2

Old 24th Apr 2013, 00:20
  #21 (permalink)  
 
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United 787 KLAX to KSKF today

I've been looking at FlightAware for 787 flights several times a day lately, expecting to see a flurry of the Boeing aircraft caught on the ground before customer delivery going up for B-1 flights and such. But, aside from the engine testing flights ending last week under the ID BOE5, I've not been shown any in flight so far (the aircraft type method only detects aircraft in flight--though with a flight number you can see history as well).

Instead, today, I saw a flight under a 4-digit United flight number listed as a 787 flying from Los Angeles International to Lackland AFB.

While this could just be a mis-attribution, I'm inclined to guess it was real. LAX was listed as the location where one of the United 787s was stranded, and I believe that some kinds of 787 work get done at Lackland. The past history of the flight number did not show other KLAX to KSKF operations under that ID recently.

If it was real, then either someone gave special dispensation for the flight to be operated without the battery fix, or this is a bird that got the fix in already.

Can anyone here correct, expand, confirm, or deny?
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Old 24th Apr 2013, 00:48
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I can check it out, do you have the designator?

Edit: got it 6850

Last edited by FlightPathOBN; 24th Apr 2013 at 00:51.
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Old 24th Apr 2013, 00:55
  #23 (permalink)  
 
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UAL 6850

This link will allow detail to be seen for the next few days for the FlightAware listing of interest. (assuming PPRuNe forum software does not corrupt it).

The line of interest is for a flight from KLAX to LSKF departing KLAX at 11:19 a.m. PDT on 4/23/2013.

UA 6850 on flightaware

UAL 6850
(edit: you got the answer before I replied, but I'll leave the link up in case it might interest someone else)

Last edited by archae86; 24th Apr 2013 at 00:56. Reason: acknowledge previous post
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Old 24th Apr 2013, 01:04
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CHICAGO (AP) — United Airlines says it flew one of its 787s to a Boeing facility in San Antonio on Tuesday for the battery fix it needs to resume flying.
United has six of the planes. They've been grounded worldwide for three months because two of them had smoldering batteries. Boeing's proposed fix has been approved by the Federal Aviation Administration. Last week the FAA approved non-passenger flights for the 787 like the United flight that left from Los Angeles.
United Continental Holdings Inc. says Boeing Co. workers will install the fix, with help from United mechanics. Boeing has said the battery system modifications will take about five days per plane to install.
United has 787s in its schedule for May 31, but it has said that flights might resume earlier.
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Old 24th Apr 2013, 04:34
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airworthiness factual report error

In the airworthiness factual report there appears to be an error on page 16 concerning the JAL APU start power consumption.

The Flight Data Recorder report shows measurement DCBus_APU_Battery_Current (A) in figure B-12 on page 10B-13 only discharging an average of about 20 amps for the APU start with a momentary spike up to 30 amps during the 35-second discharge.

This would only be 640 watts average with the spike at 960 watts, not the 9.6 kW (32V x 300A) mentioned in the airworthiness report. Some of the other power figures in that paragraph appear incorrect also and should be re-checked.

In addition I wanted to point out that same FDR current data also shows that the APU battery was constantly being overcharged by trickle-charging at 1 to 2 amps during the 14 minutes between Last Engine Shut Down and the APU Shuts Down event.

The Securaplane battery charging patent #5,780,994 is based upon a Ni-Cd battery charging profile and assumes a trickle-charging phase of indefinite length following the fast-charge phase.

GS Yuasa does not include trickle-charging in the CC/CV charging procedure found in the LVP10-66.pdf data sheet for the cells, nor does any other manufacturer of Lithium chemistry batteries.

The CT Scan report also provides evidence of overcharging in the scans of the "normal undamaged" Main battery. The cell walls are clearly seen to be bulging outward and there may be cell-to-cell wall contact. This swelling of the cells is also seen in the CT scans shown in the JTSB reports for the "undamaged" APU battery of the ANA aircraft.

I have a mechanical load analysis which shows that only a couple of psi delta-pressure is necessary to deform the 0.031" stainless steel material used as the cell case. A deformed cell case would likely cause internal short-circuit contact of the current collector bars to the case leading to cell thermal runaway such as was experienced in both battery incidents.

The source of the pressure delta could be internal due to overcharging, and/or external due to operation at reduced atmospheric pressure such as in high altitudes (e.g. 6000 ft).
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Old 24th Apr 2013, 09:44
  #26 (permalink)  
 
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Perfect for spotters corner

There was a single United 787 parked out in the open at the south of the western maintenance area at LAX about 2 weeks ago. Is it still there?
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Old 24th Apr 2013, 10:59
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Surprised!

When I said in post #742 (thread 1) that there is:-

No powered plane without fire
Aeroplanes have been living with fire (in their engines) for over 100 years. This COULD be a precedent for permitting (inadvertent) fires in another power source, the batteries, provided it was as well contained as the engine combustion???

I did not seriously think that they WOULD do it.

PS I accepted the correction that there are some powered aircraft without fire.
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Old 24th Apr 2013, 11:28
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Oh but we meant to do that

In the new set of documents that was just released on the NTSB Docket site. On docket # SA-536, exhibit # 17-A, Airworthiness Excerpts from Boeing Battery Specification Control Drawing:

page 89, section 3.2.4.13, Charging Requirements
The fully charged battery shall accept continuous overcharge at _ V without explosion or damage to the battery case.

The blanked out voltage was redacted due to proprietary concerns.

So it looks like Boeing wrote a requirement on the battery that might be fine for Pb or Ni-Cd but violates the fundamental law of Lithium battery chemistry...
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Old 24th Apr 2013, 16:26
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Something I heard the other day.
The battery vent indicator burst-disc keeps blowing off in flight. The fix is to place the disc at the other end of the vent tube. IE. at the battery containment box.
It is a weekly check item to ensure this disc is intact.
The only way to check it is to remove the 52 bolts from the lid and do an internal inspection.
Takes about 3 hours apparently.
This may well be a load of BS as I haven't had it confirmed yet.


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Old 24th Apr 2013, 17:15
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Yesterday, the guy from Boeing stated that if there are any issues with the battery, there is an alert to the crew, and that any battery alert prevents dispatch.

It should be interesting to see how that plays out...

edit: awblaine...note post#24 above.

Last edited by FlightPathOBN; 24th Apr 2013 at 17:16.
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Old 24th Apr 2013, 22:38
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How could bursts have been frequent

Originally Posted by TURIN
the battery vent indicator burst-disc keeps blowing off in flight.
While I love to get inside information here, there seems to me a little problem with this account: the very small number of flights to date of the revised system.

Famously there was just one in the certification plan for the revised battery system. Also, I think, a handful under flight number BOE5 handling certification for an engine upgrade (mostly last week). Other than that, the reported recent flights (UAL ex Los Angeles, Qatar ex London) seem to have been relocations still carrying the old system.

My doubt on the runup to the situation does not address the possible truth of the weekly inspection requirement, which would be an unwelcome addition for several reasons. Still, 3 hours seems rather a lot unless the paperwork enormously outweighs the inspection work.

Please advise if you get updates on any aspect of this.
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Old 24th Apr 2013, 22:59
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Yes, I took it with a pinch of salt but I just thought I would throw it out there just to get a confirmation. 3 hrs seemed a bit excessive to me too.


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Old 25th Apr 2013, 00:23
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Well, look at set up, then unscrewing 52 bolts...doing what you have to do, then placing and tightening 52 bolts...(at Union scale)

Given the picture, one could easily see 60 seconds per bolt sequence...
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Old 25th Apr 2013, 02:58
  #34 (permalink)  
 
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14,000 cells built since 2001

and never had an internal short-- according to the GS Yuasa representative in today's hearing. These are the industrial cells of the same construction as the 787 cells, but using a different chemistry.
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Old 25th Apr 2013, 05:16
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So it looks like Boeing wrote a requirement on the battery that might be fine for Pb or Ni-Cd but violates the fundamental law of Lithium battery chemistry...
Having reviewed parts of the Day 1 NTSB hearing, and looked at the rough transcription; it seems that no one has questioned the over-voltage charging regime, nor the CV trickle charging.

The transcription mentions the cell OCV as 4.55V, then a little later reconfirms this figure by stating that for the battery -
We also do a test where we charge at 36 volts for a long time
So, it would appear that the 36V [36.4] figure has been redacted from the Airworthiness Excerpts now released.
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Old 25th Apr 2013, 06:10
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Installation Progress, 10 + 9

Michael Mecham posted on Aviation Week's Things with Wings blogs a comment attributed to Boeing Chairman and CEO McNerney that the fixes "were installed" in "10 fleet aircraft and 9 production aircraft". That sounds like "all done".

Mecham battery progress post

However, a Boeing VP posting in his own voice on his own blog, VP Marketing for Boeing Commercial Airplanes, describes it as "We’ve started installation on 10 787s already in the customer fleet, as well as nine production airplanes. The bulk of the fleet retrofits should be wrapped up by mid-May. 787 deliveries are expected to resume in early May."

Tinseth blog (look for the second paragraph of the entry which first mentions the quarterly earnings report. It is the top entry at the moment I am posting, but will move down).

I don't usually expect the Marketing channel to have the more accurate story, but in this case my bet is on Randy, not on McNerney as quoted by Mecham. Boeing has elsewhere described the installation as taking about 5 elapsed days on an airframe, and I think they did not start customer fixes nor most in-process birds until the approval came through. I'm talking about bending and cutting metal and composite--not about pre-positioning people and materials, which clearly happened. Randy comments in his post that he was in Ethiopia at the time of writing. I'd guess that may hint that the widespread story that Ethiopian may be the first airline flying seems more likely than some may have thought.
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Old 25th Apr 2013, 15:29
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It is interesting the amount of detail that has been shown for the box in the rear bay. I bet it is a real bitch getting that thing installed in the fwd EE bay....
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Old 25th Apr 2013, 15:29
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@mm43

Having reviewed parts of the Day 1 NTSB hearing, and looked at the rough transcription; it seems that no one has questioned the over-voltage charging regime, nor the CV trickle charging.

The transcription mentions the cell OCV as 4.55V, then a little later reconfirms this figure by stating that for the battery - Quote:
We also do a test where we charge at 36 volts for a long time
So, it would appear that the 36V [36.4] figure has been redacted from the Airworthiness Excerpts now released.
I doubt they production test at 4.55V Per cell, as it would do irreparable damage and set cells up for failure within a short time - seconds - thereafter.

Actually, FDR at BOS shows charging after the first cell beginning to short - up to 4.57V for the remaining 7 cells - 32 / 7.
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Old 25th Apr 2013, 20:05
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Acceptance testing at ~5000 ft

According to Thales in the Battery Acceptance Test Procedure general ambient conditions for all tests were performed with atmospheric pressure from 84 to 107 kPa, temperature at 25 +/-10 C.

The Thales Climatic Environmental Qual Test Report has altitude, decompression and overpressure testing, but all the values are redacted.

If cabin pressure is held at that of 6000 ft altitude and also maintained all the way into the Main and Aft E/E compartments, then the delta-pressure across the cell walls is on the order of -2.9 psi, which will cause the cell cases to swell and bulge out such as is seen in the CT scans of the exemplar batteries from both Boston and the ANA battery events.
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Old 26th Apr 2013, 16:49
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More documents released....

The online NTSB document access system (http://dms.ntsb.gov/pubdms/search/do...251&mkey=85973) just had 36 new documents added to it, most relating to new certification. Have not had time to read any yet.

Last edited by inetdog; 26th Apr 2013 at 16:52.
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