FAA Grounds 787s
I suggested that a big, red," reserve battery emergency destructive supply" button could be placed in the cockpit, where the humans could override the system if that was needed to save the aircraft.
The specialist teams that were brought in provided fixes for all the potential problems and those that had been found.
If Boeing does discover the cause and goes back to the drawing board with an updated design, the FAA (and others) may give them a clean sheet of paper, so to speak, on battery reliability. Eventually, the battery box could go. However, if they continue as is, how much reliability data do they have to collect with the current 'probable fixes' in order to demonstrate something on the order of one event in the life of the fleet. I'm not going to do the numbers here, but my gut feeling is that this will only be provable over a significant fraction of the fleet's lifetime. Hence the perpetual battery box.
I know a few of the engineers left at Boeing. This problem goes well beyond their remaining base of expertise. Some smart battery subcontractor may find the solution and Boeing may put its stamp on it. But recertification is going to be expensive and not likely something a sub is going to finance out of the kindness off their heart.
Why? The danger has been averted. Even if nobody understands what is going on within the battery box, the aircraft should be safe regardless.
still not going to fly on one, yet.
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Quote:
I suggested that a big, red," reserve battery emergency destructive supply" button could be placed in the cockpit, where the humans could override the system if that was needed to save the aircraft.
I suggested that a big, red," reserve battery emergency destructive supply" button could be placed in the cockpit, where the humans could override the system if that was needed to save the aircraft.
So as an analogy, I'll just run my business knowingly leaving lots of fire hazards lying around because I know my sprinkler system extinguishes fires?
Last edited by Cows getting bigger; 2nd Jul 2013 at 16:26.
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EEngr
No the battery box will stay it is part of the RTCA standard for LiIon - even the new Cessna Citation has one.
Some people will remain unconvinced, however there was a large task force of industry experts most from outside Boeing who identified all the faults that could cause problems and fixes were put in for those.
Boeing wins nothing by trying to get out of testing or by not making a complete fix,. There only needs to be a minor problem of any type and all the naysayers here will shouting about it; another 787 battery problem would be a company challenging event.
If Boeing does discover the cause and goes back to the drawing board with an updated design, the FAA (and others) may give them a clean sheet of paper, so to speak, on battery reliability. Eventually, the battery box could go.
Some people will remain unconvinced, however there was a large task force of industry experts most from outside Boeing who identified all the faults that could cause problems and fixes were put in for those.
Boeing wins nothing by trying to get out of testing or by not making a complete fix,. There only needs to be a minor problem of any type and all the naysayers here will shouting about it; another 787 battery problem would be a company challenging event.
You are joking, yes?
I'm not making a value judgment on whether this is a proper fix from a professional engineering point of view. And whether they will pursue the investigation further. That's something the company and regulators will have to weight on their conscience.
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My understanding is that the criteria has remained the same but the charging minimum voltage has been increased to prevent the battery going into shutdown mode.
If Li cells are discharged too far you cannot safely recharge them. The charging minimum voltage is the voltage at which it goes into shutdown to prevent charging.
If you raise that voltage limit you make the battery safer but you increase the number of batteries that will shutdown due to over discharge.
Last edited by cwatters; 3rd Jul 2013 at 07:15.
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If you raise that voltage limit you make the battery safer but you increase the number of batteries that will shutdown due to over discharge.
My tuppence worth.
My understanding of the refined battery system.
The min discharge level has been increased. This will shut the battery down at a higher charge, but will mean that it can still be recharged in-situ if normal power is returned to the a/c.
EG A non-APU towing scenario, on bat only. instead of, say, 30 mins of useable power from the bat, one may only have 25 mins. The bat circuit automatically shuts off power and then when the GPU is connected the battery will recharge.
I could be wrong, but this seems the most logical outcome, otherwise we are still going to be changing batteries ad-nauseum due to towing operators not monitoring the bat state.
My understanding of the refined battery system.
The min discharge level has been increased. This will shut the battery down at a higher charge, but will mean that it can still be recharged in-situ if normal power is returned to the a/c.
EG A non-APU towing scenario, on bat only. instead of, say, 30 mins of useable power from the bat, one may only have 25 mins. The bat circuit automatically shuts off power and then when the GPU is connected the battery will recharge.
I could be wrong, but this seems the most logical outcome, otherwise we are still going to be changing batteries ad-nauseum due to towing operators not monitoring the bat state.
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@TURIN
Obviously the only one in class who looked and absorbed 
Baaaack in the early days of the thread, I stated that Li-Ion .Li Poly technology, though having very high energy-density, had significant operational drawbacks.
Safe , repeat charge-discharge cycles rely on a strict care-regime.
ALL cells in a pack MUST be balanced when charging.
ALL cells should only use the "middle-portion of their capacity....IE charging should be cut off at a critical value BEFORE maximum potential cell voltage
all cells should be only partially discharged, leaving a critical ,safe-voltage residual charge.
IF THIS REGIME IS FOLLOWED, very high rate discharges are available with very high reliability. The downside being reduced available capacity*
Spontaneous combustion is not unknown, but bear in mind, these are NOT 12,000 dollar packs, NO! they're less than 100, typically, and operated by amateur enthusiasts in public places and insurers are quite willing to offer affordable cover.
Back to the core argument, which was The battery has to be able to drain completely to self-destruction in order to maintain basic instruments and braking , in event of failure of all power-generation sources.
THAT'S where the BIG RED OVERRIDE BUTTON comes in.....just like the Cirrus parachute, it's always there, you should never need it, but in that highly improbable 5h1t or bust situation, it offers a "get out of jail " card to access the last portion of the stored power in the batteries (destroying their rechargeability in the process)...but that's little price to pay for a monitoring and protection system which maintains the batteries within their safe operating-envelope and stops "unskilled" personnell taking them outside those parameters (which is the alleged reason so many were "locked-out" and had to be field-changed- 150 units across a fleet of 50??)
* The reduced capacity, in turn, bought into question the marginal advantage of using this Vs. one of the lower energy-density but safer Li. technologies.
There now, that's saved a mammoth trawl through all the dross and diamonds , hasn't it?
Obviously the only one in class who looked and absorbed Baaaack in the early days of the thread, I stated that Li-Ion .Li Poly technology, though having very high energy-density, had significant operational drawbacks.
Safe , repeat charge-discharge cycles rely on a strict care-regime.
ALL cells in a pack MUST be balanced when charging.
ALL cells should only use the "middle-portion of their capacity....IE charging should be cut off at a critical value BEFORE maximum potential cell voltage
all cells should be only partially discharged, leaving a critical ,safe-voltage residual charge.
IF THIS REGIME IS FOLLOWED, very high rate discharges are available with very high reliability. The downside being reduced available capacity*
Spontaneous combustion is not unknown, but bear in mind, these are NOT 12,000 dollar packs, NO! they're less than 100, typically, and operated by amateur enthusiasts in public places and insurers are quite willing to offer affordable cover.
Back to the core argument, which was The battery has to be able to drain completely to self-destruction in order to maintain basic instruments and braking , in event of failure of all power-generation sources.
THAT'S where the BIG RED OVERRIDE BUTTON comes in.....just like the Cirrus parachute, it's always there, you should never need it, but in that highly improbable 5h1t or bust situation, it offers a "get out of jail " card to access the last portion of the stored power in the batteries (destroying their rechargeability in the process)...but that's little price to pay for a monitoring and protection system which maintains the batteries within their safe operating-envelope and stops "unskilled" personnell taking them outside those parameters (which is the alleged reason so many were "locked-out" and had to be field-changed- 150 units across a fleet of 50??)
* The reduced capacity, in turn, bought into question the marginal advantage of using this Vs. one of the lower energy-density but safer Li. technologies.
There now, that's saved a mammoth trawl through all the dross and diamonds , hasn't it?
Paxing All Over The World
Is Boeing too big to fail?
In crisis they will be rescued by whichever administration is in power. As the only commercial airliner manufacturer left in the USA, even before you count their military contracts. It does not matter what they state at the time: money/jobs/national security (probably all) there is no doubt that Boeing will not be allowed to fail. The 'always free market' of the USA will do what it always does and good luck to them.
Is Boeing too big to fail?
But there's also the issue of the FAA's dual charter: Maintaining the safety of aviation and promoting it. I'll give the NTSB kudos for pushing for the actual answer to the battery problem. But in the final analysis, their role is only advisory. And the FAA chose to stop short of making the Big Battery Box an interim solution and demanding further investigation.
I'm not so worried about flying on a 787 modded with the BBBox. But allowing systems to be certified by an organization that says "We don't know how this works" bothers me. Would you get on a plane if the manufacturer didn't know what keeps them up in the air? [Not that far-fetched. I've lurked in PPRuNe threads about what causes lift.
]
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'But think of the shareholders.'
Silly me, I always thought there was an element of risk to being a shareholder but perhaps that's so 20th century .
Would you buy a mortgage-backed security, a collateralized debt obligation or any other derivative? No one knows how they work either but they still sell.
But back to the 787. Are their teething problems related to the current dearth of engineers and/or the surfeit of MBA's?
Silly me, I always thought there was an element of risk to being a shareholder but perhaps that's so 20th century .
Would you buy a mortgage-backed security, a collateralized debt obligation or any other derivative? No one knows how they work either but they still sell.
But back to the 787. Are their teething problems related to the current dearth of engineers and/or the surfeit of MBA's?
But back to the 787. Are their teething problems related to the current dearth of engineers and/or the surfeit of MBA's?
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Are their teething problems related to the current dearth of engineers and/or the surfeit of MBA's?
Boeing Corporate Offices. 100 North Riverside Chicago, Illinois 60606.
What aircraft, or even bits of Boeings get built in Chicago? Head office too far from the coal face?
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MBAs in Chicago telling engineers in Seattle how to do business?
Was reading an article a few days back how the new CEO from a well off multinational is selling off the assets ( buildings, profitable subsidiaries, etc..) to raise capital /pay dividends/ boost share value under his chairmanship. All this to raise his profile, in order to move to the next company with a good CV record, and to do probably the same again there.
Who's in those spheres are interested about the products actually manufactured ?
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EEngr noted:
The regulatory agencies - be they the American FAA, European EASA, Japanese JAA, or whomever - don't have the knowledge that the OEMs (Boeing, Airbus, etc.) have which is why they are dependent on the OEMs to assist them in the certification process. And the OEMs themselves depends on the system sub-contractors to assist them in the certification process. Boeing and Airbus are not experts in Li-Ion batteries, so both were assisted by the subs developing those batteries to develop the certification and testing process.
And this practice is not just in commercial aerospace. Many industries depend on the assistance of those being certified during the certification process.
Why wouldn't Boeing like the identification of the root cause? Knowing how and why something happens is an important step in determining how to prevent it from happening again.
But allowing systems to be certified by an organization that says "We don't know how this works" bothers me.
And this practice is not just in commercial aerospace. Many industries depend on the assistance of those being certified during the certification process.
Having an open-ended investigation into batteries, electrical panels, loose bolts, etc. might lead regulators to a root cause that Boeing won't like.
Why wouldn't Boeing like the identification of the root cause?
I was working there in the 1990s when the FAA uncovered major QA problems with aircraft subsystems. The FAA finding and remedy (which I was involved with) was to clean up the functional testing process. And that involved holding design engineering's feet to the fire to take their (FAR mandated) responsibility for overseeing that testing seriously. Boeing management screamed like a stuck pig, but made the required process changes. It was either that or lose their manufacturing certificate. The changes interfered with Boeing's strategy to push engineering tasks out to subcontractors. But only for a while. By the time I left, they were back on track outsourcing everything.
If current problems can be tracked back to a lack of end-to-end oversight from design engineering through to manufacturing and quality control, Boeing might be stuck with some major reorganization.
