A succession of problems has plagued Boeing's 787 Dreamliner, but investigators are now most concerned about incidents involving overheating of lithium-ion batteries.
Federal Aviation Administration (FAA) officials grounded Boeing's high-tech Dreamliner after battery electrolytes reportedly leaked from a lithium-ion battery onboard an All Nippon Airways flight on Wednesday. The liquid reportedly traveled through an electrical room floor to the outside of the aircraft, leaving burn marks around damaged areas.
The latest incident followed on the heels of two battery-related problems encountered on Japan Airlines flights and another on a United flight earlier this month. Those incidents happened in parallel with multiple other episodes, including two fuel leaks. Since July, the 787 has also encountered a damaged cockpit window, an oil leak, and two cracked engines, according to multiple news reports.
Auxiliary power batteries onboard a Japan Airlines Dreamliner 787 caught fire at Boston's Logan Airport on January 7. The battery was taken back to the National Transportation Safety Board's Materials Laboratory in Washington for further examination. (Source: NTSB)
Aviation experts said most of the problems are unrelated. "I tend not to believe that there's a single root cause behind all of this," David Freiwald, an assistant professor of aerospace at Embry-Riddle Aeronautical University, told Design News. "Any new system has teething or growing pains. A few issues are to be expected."
The incidents did motivate aviation authorities around the world to order stoppage of Boeing 787 flights, however. The FAA also announced it will work with Boeing engineers to conduct a comprehensive review of the 787's design and manufacture, with an emphasis on the aircraft's electrical power and distribution systems.
On its website, Boeing emphasized the safety of its new aircraft, releasing a statement saying, "The airplane has logged 50,000 hours of flight and there are more than 150 flights occurring daily. Its service is on par with the industry's best-ever introduction into service -- the Boeing 777. Like the 777, at 15 months of service, we are seeing the 787's fleet wide dispatch reliability well above 90 percent."
Most of the concern around the 787 involves the use of lithium-ion batteries. The 787 is the first commercial aircraft to employ them. Its electrical architecture also operates at a higher voltages than predecessors, experts told us. "In terms of the ancillary systems, almost everything on the 787 is electrical," Freiwald said. "Most aircraft systems operate at 115V AC, whereas this is a 230V system. It's a pretty substantial amount of power and current."
Freiwald added that the lithium-ion batteries are used for auxiliary power back-up. In the past, he said, commercial airliners have typically used nickel-cadmium chemistries.
Battery experts told Design News that the choice of a lithium-ion chemistry shouldn't be a problem, but it does call for tighter control. "Lithium-ion is a pretty energetic material," Eric Dietz, a professor of computer and information science at Purdue University, told us. "You've got oxidation and reduction reactions happening in close proximity to one another, so it's important to maintain engineering control around the battery."
They obviously overlooked the battery design slightly in the initial stages of development. At least no one was hurt, but I am sure Boeing will fire a few on the battery team. With all the battery exploding incidents from the past, I am surprised that wasn't a concern for the engineering team. However, it could have been a manufacturing error.. Time will tell.
Liaison engineers have commented previously that Boeing may have done too much too soon with this aircraft.
We have had lithium systems problems in E scooters where thermal overload shut down the 48V system via the batteries management software. We concluded that heavy current draw during acceleration was causing the problem and tried conditioning that by tweaking the controller
How often we recommend that you always make one change at a a time in anything new. Boeing changed so many things at once it is remarkable the plane flew at all! I'm a big Boeing fan, but me thinks your bite was too big for thy mouth...
Chuck, Very interesting report. It's amazing how with a system as complex as the Dreamliner, there are a very large number of unknown variables to resolve. Tough for the Boeing engineers who are moving a project of this scope into the marketplace, especially in a spotlight as bright as this situation.
I agree, Al. The spotlight is very bright in this case. I initially wondered if the bright spotlight might be part of the problem here. But the succession of battery overheating incidents in January alone is hard to ignore.
It's interesting that this is the same technology that Ford just standardized on. While the article mentions the cooling systems used in autos and some of the other design components, I can't help but wonder what can happen a few years down the road in vehicles that are not properly maintained...whatever the definition of "properly" may be with respect to battery safety.
Lithium-Ion chemistry is also used in the Chevy Volt, the Fisker and other electric vehicles (but notably not in the Toyota Prius). Li-ion is a very energetic chemistry, which is necessary to pack so much energy in a limited volume. Gasoline is even more efficient, so much so that it can explode in situations where Li-ion batteries would only burn.
Yes, indeed you can pump out the thermal energy, depending on the coefficient of productivity (COP) of the system. For typical air conditioning systems the COP is about 4.0
SystemsGuy, my understanding is that this battery came into play only on the ground, i.e. something to do with landing gear controls or something. So high altitude cold air doesn't help that situation much.
In any case, flight controls probably get their biggest workout getting to altitude or landing, all lower altitude issues, and must be designed for the worst case.
The description of the meltdown seems that they might be using lithium cobalt, not a good design choice if that is the case. Lithium iron phosphate LiFeP04 would be the only safe choice. Anyone know what Boeing used?
Very good point, davemiga. I've heard -- unofficially -- that it was cobalt, but haven't been able to verify it. And, yes, a cobalt chemistry is slightly more susceptible to overheating, although all lithium-ion chemistries are on the edge (with the possible exception of the so-called "nanophophate" chemistries).
I find it ironic that the 787 uses high capacity Lithium Ion batteries for its standby/startup power when such batteries onboard as cargo have had severe restrictions placed upon them in the past. For example UPS considers batteries with a watt/hour capacity greater than 20 but less than 100 to be shippable but only when handled as hazardous material. Anything above 100 Wh is not shippable by air according to UPS. This for a disconnected, not in service battery!
The IATA bans cargo shipments of primary cell Lithium Metal batteries from all passenger planes. Obviously, the button cell in your wristwatch is okay as long as it isn't part of a cargo shipment.
The IATA regulation of 100 Wh or less for secondary Lithium Ion batteries has been the limiting factor for available run time for professional video cameras.
Overcharging is well known to cause overheating. The charging system and overheating protection system need to wwork to prevent this. Apparently this has not been completely effective. I would look carefully at the charging system to see what unusual conditions may exist. Perhaps the intense cold in the exterior environment could trick the charging system into overcharging.
At first all the failures may look unrelated due to the fact they all perform different functions on the Airbus.
But before a general comment can be made as in the article, as an engineer, I would investigate the specifications requirements from all these peice parts and check in- fact they have been enviromentaly accepted for high altitude low atmospheric pressure, Vibration of jet engine frequency and air turbulance of sympathetic oscillations, and extreme temperature changes mostly cold temps.
Now if we take all these into effects, I bet we might find a common thread. It cost $$$ for screens like this and BOEING could have cut cost by using "COTS" of the shelf items.
The Lithium batteries were once not allowed on board plane in laptops because of inherient design issues that caused a possible fire. What has changed with Lithium batteries to make them safe???
Someone in BOEING is an Engineer of poor judgement....Not the structure of the aircraft but selected components not purchased properly for the job is whats at fault.
I bought a Cadillac and the dealer gives me a Chevrolet...get my point
Paul, even with the extremely greedy industry attitude nowadays, I doubt Boeing purchased such kind of batteries. Aviation is characterized by very high standards, but in these days, some goofes can (and doo pass).
For me it is another (of the many) cases of bad results derived from the abuse of that "modern" practice of outsourcing. Not that outsourcing per-se is bad, but the ever growing tendency of completely relying on subcontractors (that sense of "lets the supplier take care of this and forget" attitude that has its roots in so called modern administration practices, that permeate companies previously known for their reliable products.
Trying to push out a completely new design, that has many advances at the same time requires a proportionately larger and more trained workforce, so the MBA geniuses at top level decide to place an often too large share of design, integration and testing on outside subcontractors, and in theory, they instantly kill any problems! This is a world-wide tendency courtesy of latter generations of so called 'professionals' that appear to have all the credentials that (apparently), qualify them as experts. As older generations of old-fashioned engineers retire, the new ones arrive to the scene looking as disproportionately capable ones, that rely too much on software aids, simplified methods and a generalized lack of true hands-on real life experience. I seriously doubt how many of those engineers have actually seen a small Lithium battery pack as it catches fire? (One of my hobbies is Model Airplane building and flying, and there are some high temperature ceramic pots sold in the hobby market, designed precisely to contain those relatively small batt packs if they decide to ignite under charge -or storage-, for that matter!).
Regarding the general attitude towards too much confidence or reliance in a given supplier, certifying body or industry in general, I'll give you an example:
I read about two weeks ago: Daimler and Volkswagen decided to defy the European Union Jan. 1 deadline that orders the use of a new, 'ecologically friendly' refrigerant that should replace the widely used R134a, owing to the results of realistic automobile crash test performed in houseby Daimler engineers, that resulted in fires, even when the DuPont-Honeywell new refrigerant has been enthusiastically promoted as a "safe" and much more "green" substitute for R134a. The fact is that the same companies have promoted the new product as "only slightly flammable" (if such term is plausible). the exact phrase said "It is well known that HFO-1234yf is a mildly flammable refrigerant," [Diane Iuliano Picho, global business manager, Opteon™ refrigerants.]
The good guys at GM quickly jumped on the bandwagon and publicly announced they swear at the product and will happily use it!
This shows that industry, suppliers, and even governmental testing bodies, all can be persuaded in a given moment to favor (or allow) the use of a new product, as it represents "innovation" (DuPont's Terrence Hahn reportedly said: "The key element for the EU government is forcing the implementation of their rule," said Terrence Hahn, general manager of the U.S. company's fluorine products unit. "If you are not doing that, you are going to severely dampen innovation..."
In the B-787 case, over relying on the supplier for the battery system for everything, is like relying on the publicity published by the freon replacement manufacturer in order to declare the system "safe". In the refrigerant case, it is curious that the Daimler engineers were able to produce a crash fire when several others weren't. I applaud them, and applaud both Daimler and Volkswagen for defying the dumb politicians of the EU, the same people that gave us the ban on leaded solder and other measures that fit well the "Law of uninntended consequences".
It is not difficult to perform an illustrating experiment: take a little cooking oil, placed into a cup it is hadly flammable, but put into an old parfume sprayer, press the rubber bulb and the same oil ignites with incredible violence. I doubt some self appointed experts have actually performed this simple experiment. No amount of wishful thinking or babying will bend the laws of physics (or chemistry). There is no substitute for experience. Amclaussen.
It's difficult to find what the fault is on a problem like this. These projects have extensive testing (i am an aviation test engineer). It could have been many things that lead to this issue. (Might not even be related with the battery at all). It's a very large system with many components and the battery is the weak link. I am confident that FAA and Boeing will find a solution and this plane will fly again. Let's not jump to conclusions and let's wait on an official announcement from FAA or Boeing.
I am not associated with FAA or Boeing. It's a marvel that these metal birds can fly. This happens all thanks to companies like Boeing.
Absolutely! but sometimes people, not withstanding how competent or well trained, perform incredibly simple (as an after though) errors. All aeronautical companies do, from time to time, execute some grave ones. Remember the control valve on the Rudder Control Unit of the B-737... Or the software glitches of the A-320... or the uncommmanded thrust reverser openings on the Fokker-100. In a large number of these catastrophic failures there is an identifiable dose of incomplete testing. The Wright Brothers were 1) very knowledgeable and, 2) fully committed to testing, so that they were able to survive for quite a few years. Blind faith or 'confidence' should not be in the vocabulary of an aviation expert, my two cents. Amclaussen.
I am confused. "It's a marvel that these metal birds can fly." I thought the point of this plane was it is plastic? As a sailor I can tell you plastic, wood or metal, fire is not a good thing. If that thing in the lead photo was the "battery" then I see why they grounded them until this gets sorted out. As aviation test engineer you of all people should know this will be resolved. While I really don't know anything about it I am still of the opinion that these planes do not fly anymore than a fully loaded and fueled B52 flys, once off the ground they are at all times in a controlled fall. Even sailplanes and hang gliders don't fly, they soar. How can they fly 5 miles up where there is little "air"? That makes no sense. Now massive amounts of air pressure pushing on the bottom of the wings to get them in the air, that I can believe. Massive power continuing them in the direction they are going, that I can believe. People tell me I am wrong and they wing shape really does generate enough lift but I don't see it.
You are right I was thinking more in line with 777 and 787 since they are still flying.
Some basic info on how a plane flies. This is a physicist's view (so most likely incorrect). You transfer enough kinetic energy to potential energy (exhaust of the engine is kinetic, plane flying is potential energy) and the object flies. The reason the object flies is because the air flowing around the wing provides lift hence the plane does not convert the potential energy to kinetic by falling. The downside and the reason engines need to remain on during flight is drag on the plane. Drag (air friction) slows down the plane converting some of the potential energy into heat. The engine has to burn fuel and input more energy into the system to insure we don't loose enough potential energy to loose altitude. As far as thin or thick air that only effects drag and efficiency of the airplane. The thinner the air the faster you need to go to maintain the same amount of lift or more wing span (seeing that wingspan is fixed we tend to make airplanes go faster). Also keep in mind that these engines output 240-330 kN of force. That force is enough to suspend 60 tons of mass. Now yes an airplane is far greater than 60 tons I think Dreamliner tops at 500. Keep in mind that we only have to defeat drag to make it fly we don't have to supply enough force to lift it straight up.
@Ervin- I'm a pilot and engineer, and your aerdynamic theory is more or less correct. As you state, planes don't fly by converting PE to KE by falling. But without gravity there won't be a lift vector; a subtle but important distinction. BTW an airliner is a surprisingly efficient glider...I'd guess a 20:1 glide ratio is typical.
Airflow over the top contour of the wing is critical while the underside of the wing less so. (Next time you see a plane, look at the designed-in smoothness of the top of the wing compared to the bottom). Frost, insect contamination, or a paint step can drastically or completely destroy lift if it "trips" the laminar flow over the top of the wing. So will going too fast if airflow over the top of the wing accelerates to supersonic, called a "Mach stall". (The 777 and other newer planes use a "supercritical" airfoil that allows it).
"The thinner the air the faster you need to go to maintain the same amount of lift"..this is called Indicated Airspeed and True Airspeed. For a constant amount of lift, IAS will be the same at sea level or 40,000 feet. As the term implies, it's the number of air molecules the plane encouters per unit of time. That produces a ram pressure that the pilot sees on the airspeed indicator. But, in thinner air the plane can go faster before it encounters the same ram pressure and drag. IAS to TAS is a pretty complicated equation. A 767 at cruise altitude may have a TAS of 500 knots (= groundspeed with no wind) while IAS is 325 knots.
Airliners are one of the most high-tech machines you will encounter in daily life. It's amazing they perform so reliably and safely. The 4th anniversary of US passenger airlines being fatality-free is a few weeks away. About 3 billion people carried on 40 million flights!
max take off weight of 787-9 is 251 metric tons (modification for long distanses 15700km), total force from engines 64.4tons
amazingly 787-3 (not in production) has near 170 tons weight and flight distance 5500km, total engine force 48 tons - look like very different plain, but with same design & engines.
I am more interested to find a common fault with all the unrelated components of the 787. Such as the idea that Boeing left it up to the subcontractor or supply for reliable compnents to find out the forged test documrnts to meet specifications. If this is the case Boeing need to be held ownership to this.
There has been a recent problem with government purchased Off the shelf items. This was a policy put in place by Pres. Clinton to mandate reduce military cost and custom built hardware by contractors by utilizing COTS, or off the shelf equipment...Good idea?
Recently there has been virus found embedded in micoprocessors from China in American Hardware used in the military. There has been a real problem with ICs and various electronic componets removed and refurbed off of old assemblies. The component logo was removed and new log placed on devices trhat never went thru any enviroment screen and shipped and used in new products. Again the refurb supplied by China. Hence COUNTERFIET components.
Problem is that since Clinton, this problem is 20 years in the making. So before shooting bullets, WISDOM tells me further investigation is warranted as to where did all the failed comonents originate and the paperwork that was supplied to validate know good assembly procedures and proper procurment and no ties to the discussion above.
Not to say Boeing took a short cut? But unknowingly purchased conertfeit components without knowledge. I am sure the proper screening was cercuimvented or they using the 787 as the test bed???
So glad the FAA had melons big enough to ground the Hydrogen dirigible airshipHindenburg I meant to say Boeing 787...Maybe 1000s of lives have been saved.
Chuck, Nice article. The "teething pains" mentioned are not because its a new aircraft as asummed by prof David Freiwald, whom you interviewed. The teething pains are how to manage outsourcing. I have worked with several firms involved with the 787 batteries and the information flow was disturbing. Getting information from GS Yuasa was difficult on one project I worked on. When a teir-3 company is supposed to depend on a tier-4 company for its data, with no contractual obligation, problems like this will occur.
Boeing subcontacted Hamilton Sundstrand (now Pratt & Whitney) for the APU, which contained the Battery control/charger system which was subcontracted to Thales which got the battery from GS Yuasa, which bought the battery cells from.....etc etc. Has anyone played the 'whipser game' in kindergarten? I kid you not; at some meetings we joked with frustration at how similar it was.
The engineers involved in all these firms are very intelligent people and the battery issues will be worked out. Boeing management must ensure that all subcontractors are communicating.
Forbes magazine's Steve Denning hit the nail on the head in his airticle,
This is a very interesting article. Great information Charles. I'm sure a company such as Boeing has a procedure similar to FEMA (Failure Mode Effect Analysis ). I would love to see the failure mode "tree" for the lithium-ion battery application. Of course, the FEMA does NOT take the place of testing, bench and flight but it can be an indicator of "things to come" realtive to failure. In looking at the possible failure modes, severity, probability and detctability are given a number to quantify and pritorize each possible occurance. From these multiples, rankings of high, moderate and low are addressed. I have not idea if Boeing does this but if so, it would be very interesting to see.
Design News has been covering the Dreamliner for so long - it's actually a bit sad to see it come to this. The plane seems to be falling apart at the seams.
Chuck, can you give us any insight into what Boeing's next step might be? They emphasize the safety of the aircraft, but, at the end of the day, it's been grounded by the FAA ...
@Jennifer Campbell: Yes, I remember reading about the 787 in Design News back when I was in college. It was called the 7E7 then, and it was supposed to be the next big thing. Over the past few years, the news has been a lot less positive.
Another major aerospace project that got lots of "gee-whiz" press around that time, the Joint Strike Fighter, has also met with lots of delays, cost overruns, and technical problems. Now it seems more and more likely that the Department of Defense will pull the plug on the whole program.
Speaking as an outsider: what's going on with the U.S. aerospace industry? Are we just not capable of executing these kinds of big projects anymore? Are the projects just too big these days (the mutually-conflicting requirements for the Joint Strike Fighter come to mind)? Or has the development process always been this messy?
Given that the highest-profile civilian and military aircraft projects of the last decade have wound up scandalously late, over-budget, over-weight, and full of bugs, it almost seems like there is a systemic problem in the industry. But maybe this is just "normal," and I shouldn't have been naive enough to believe the hype in the first place. Or maybe things aren't as bad as they seem.
Any industry insiders care to weigh in on this quesion?
JAXA, Japan's space agency, as well as US federal investigators are planning on testing the battery type from this incident. Any news beyond "we are going to test" yet?
Seems like the batteries are the culprit, but as of now no one knows why. They've x-rayed the batteries, put them through CT scans, disassembled them and checked the associated wiring bundles and battery management circuit boards. As of now, regulators have said that overcharging doesn't seem to be the issue, but we don't know much more than that. We'll have more coverage on this coming up.
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