There has been articles telling that Boeing 787 planes are grounded over safety concerns in USA. The Federal Aviation Administration has ordered U.S. airlines to stop operating the Boeing 787, after a series of battery and fuel system failures have called into question the airworthiness of the newly developed composite aircraft. Japan’s two biggest airlines grounded all their Boeing 787 aircraft for safety checks Wednesday after one was forced to make an emergency landing in the latest blow for the new jet. Here is my collection on what I have found written on the recent Boeing 787 problems.
The 787, known as the Dreamliner, is Boeing’s newest and most technologically advanced jet, and the company is counting heavily on its success. Since its launch 787 plane has been plagued by a series of problems including a battery fire and fuel leaks. There are always teething problems with any new aircraft and airlines often are reluctant to be the launch customer of any new airplanes. You need to ensure safety, and then you also have to get people to feel that the jet is 100 percent safe. The problem here for one of America’s largest manufacturers is enormous. Developing a whole new model of airplane is expensive.
Over the years the demand for electrical power has increased in planes as new technologies such as fly-by-wire (FBW), digital avionics, and in-flight entertainment (IFE) systems are introduced. This is in addition to other power demand increases, such as the on-going change from hydraulic and pneumatic systems to electrically powered systems. Dreamliner 787 uses lots of electrical power for actuators and more, compared to earlier aircraft. Why? That’s easy to answer: in order to reduce weight and get the benefits of electronics and advanced algorithms, much of the conventional hydraulic power and control of the aircraft has been replaced by electrically-based power and control, and with advanced electronics and software, of course. Plus, the airframe is also largely made of up composites for reduced weight, instead of conventional aluminum.
Taking a Peek into Boeing 787 Electrical Power System article tells 787 will generate five times the electrical power than its predecessor (767)! 787 electrical system is 230V system (most other aircraft systems operate at 115V AC or 28V DC). The electrical power generation on board a 787 is 1.4 megawatt. The environmental control system (ECS), anti-ice system and hydraulic system are all electrically driven (making it more efficient than traditional bleed air extraction and air turbines). The electrical system is more critical to the operation of the Dreamliner than on previous Boeing aircrafts. The new electrical system has it’s benefits, but also problems. Boeing Investigates 787 Dreamliners for Electrical Issues. The More Electric Aircraft – Why Aerospace Needs Power Electronics slide set has some slides that give you some details on 787 electrical system. In 787 generator provides variable frequency supply that is directly connected to power bus. Nearly all aircraft loads will require power converters.
These electrical systems require lots of batteries for start-up, backup, and even operation. The preferred rechargeable energy-storage technology for the batteries is based on lithium-based chemistry. This makes sense, since lithium offers much, much higher energy density (by weight and volume) than any other available battery chemistry. Boeing 787 and Lithium Ion battery failure article tells that the 787 is the first airliner to make extensive use of lithium-ion batteries to help power its energy-hungry electrical systems. The batteries charge faster and can be better molded to space-saving shapes compared with other airplane batteries.
So what are the reasons behind the latest problems in 787. Lithium-Ion Batteries Emerge as Possible Culprit in Dreamliner Incidents. All Nippon Airways has ground its fleet of 17 Boeing 787s after an aircraft made an emergency landing following a suspected battery problem. ANA said a cockpit message showed battery problems and a burning smell was detected in the cockpit and the cabin. An inspection of the All Nippon Airways 787 that made an emergency landing in western Japan found that electrolytes, a flammable battery fluid, had leaked from the plane’s main lithium-ion battery. Investigators found burn marks around the damage. Keep in mind what appears to be “the problem” often is just a misleading manifestation of the real problem elsewhere.
The fluid is extremely corrosive, which means it can quickly damage electrical wiring and components. The electrolyte fluid conducts electricity, so as it spreads it can short circuits, interfere with electrical signals and make control of the plane impossible for pilots and ignite fires. Aviation experts said the energetic quality of lithium-ion can be a concern onboard aircraft. “One of the issues with lithium batteries is they get very hot,” Freiwald said. “When they ignite, they can burn so hot that Halon 1301 won’t extinguish a fire.”
We do not yet know what the official cause of the Boeing 787 Lithium-Ion battery breakdown was on the two aircraft until the full investigation has been completed. Proper Lithium-Ion battery charging and safety article have some good advice from experts in the industry that show how critical a good protection scheme is in a critical design such as on a commercial aircraft. Every lithium ion battery pack should have a safety board or IC which monitors the charge and discharge of the pack, and prevents improper conditions. Lithium-ion operates safely within the designated operating voltages; however, the battery becomes unstable if inadvertently charged to a higher than specified voltage. Li-Ion batteries commonly require a constant current, constant voltage (CCCV) type of charging algorithm. The main challenge in charging a Li-Ion battery is to realize the battery’s full capacity without overcharging it, which could result in catastrophic failure. The target charging voltage of a Lithium-Ion cell is 4.2V +/- 0.05V per cell, and the protection circuits should prevent charging above the specified safe voltage. There is very little room for error if you want to use all the capacity, especially when you are charging many cells in series (you need special battery management). Consistent overcharging can cause the plating of metallic Lithium within the cell, which will cause instability, especially if the cell is of lower manufactured quality, and especially if any moisture has been introduced inadvertently during the production stage.
Lithium-ion is not the only battery that is a safety hazard if overcharged. Lead- and nickel-based batteries are also known to melt down and cause fire if improperly handled. Automakers, many of whom use lithium-ion chemistries in hybrids and electric cars, typically operate their batteries with cooling systems. Even with cooling, however, lithium-ion automotive batteries have been known to have problems on rare occasions. Lithium-ion battery energy density is so high that there’s a lot of stored energy in that small volume, and a failure such as an internal short can result in huge current flows and subsequent fires or even explosions.
So we have the typical engineering situation of a tricky tradeoff. We want the benefits of lower weight, greater efficiency, higher energy density, and so on, but we also have to accommodate and anticipate all the implications of the technology that makes it possible. While lithium chemistry has such high density and subsequent danger, just remember that hydrocarbons such as gasoline have far greater energy density than the best batteries, yet we have managed to make that explosive technology into a safe energy-storage medium and power source.
The 787 Dreamliner Scenario: How Data Can Solve Epic Messes article tells that sensors linked to analytics and diagnostic software could help companies like Boeing solve crises more quickly. Following reports of battery failures onboard Boeing’s 787 Dreamliner, the Federal Aviation Administration (FAA) has issued an “emergency airworthiness directive” temporarily grounding the airliners. And at the moment, Boeing has a big data job on its hands: figure out the root of the battery issue—and how that issue might affect the 787’s other critical systems. 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.
66 Comments
Tomi says:
AAIB confirms fire on Ethiopian 787. Fire looks to originate from ELT
http://nyc787.blogspot.fi/
The AAIB is recommending inerting (turning off) the lithium-manganese powered ELTs and is recommending a safety review of the batteries that power the ELT. The AAIB says that the aircraft was plugged into external power but the aircraft itself was not powered up.
This means that the Honeywell supplied ELT was the source of the fire
Essentially this clears Boeing and the electrical architecture but it would be paramount to understanding the source of the combustion.
The Honeywell ELT is used in other aircraft types and have been certified for use in commercial aircraft since 2005.
ELT = Emergency Locator Transmitter
Tomi says:
AAIB Bulletin
http://www.aaib.gov.uk/cms_resources.cfm?file=/S5-2013%20ET-AOP.pdf
www.criminallawyerinnj.com/ says:
remember to help myself, i demand a lawyer. Many thanks!
fire inspection says:
You really make it seem so easy with your presentation
but I find this matter to be actually something that I think I would never understand.
It seems too complex and extremely broad for me. I’m looking forward for your next post, I will
try to get the hang of it!
Tomi Engdahl says:
Did Boeing Battery Work as Designed?
http://www.designnews.com/document.asp?doc_id=271116&cid=nl.dn14&dfpPParams=ind_184,industry_aero,aid_271116&dfpLayout=article
The 787 Dreamliner’s latest battery dustup occurred this week during pre-departure maintenance on a Boeing 787 parked at Tokyo’s Narita International Airport. Japan Airlines mechanics noticed white smoke spewing from the bottom of the fuselage and found a possible failure of the main battery on cockpit instrumentation
Boeing Co. officials insist that a smoking 787 Dreamliner battery worked the way it was designed to work. However, battery experts aren’t heaping praise on the aircraft manufacturer.
“At least it didn’t go into thermal runaway,” Ralph Brodd, founder of the lithium battery consultancy Broddarp of Nevada, told us. “It didn’t cause a fire or cause other cells to catch fire. But it also shows they haven’t really fixed the problem yet.”
During a press conference in March, Boeing officials had said that, with the latest modifications, “a fire could not begin, develop, or be sustained.” The key was the addition of an enclosure that would eliminate the possibility of fire by venting gases through a dedicated line. “If a [battery] cell were to vent, it would vent into this enclosure,” Mike Sinnett, vice president and chief engineer of the 787 program, said at the press conference. “It ruptures a burst disc in the enclosure, which allows all those gases to go immediately overboard.”
Tomi Engdahl says:
Flaming drone batteries ground commercial flight before takeoff
Passenger had Something To Declare, instead fiddled while plane burned
http://www.theregister.co.uk/2014/09/10/drone_owners_batteries_burn_in_boeings_belly/
A pile of lithium drone batteries checked as baggage on a flight from Australia to Fiji could have had nasty consequences: a bunch of the Li-Ions burned in the hold of the plane.
Fortunately for the idiot traveller whose baggage declaration said “no batteries” – and the other passengers on the Fiji Airlines flight in April – the fire was noticed before the Boeing 737 left the ground.
a ground engineer alerted the captain to “white heavy smoke billowing from the hold”.
The ATSB investigation attributes the fire to a short circuit involving the batteries, drily notes the importance of declaring batteries in luggage, and reminds travellers to pack their batteries properly to avoid short circuits.
Tomi Engdahl says:
News & Analysis
Power Week: Dreamliner Battery Fire Had Multiple Causes
http://www.eetimes.com/document.asp?doc_id=1324844&
Multiple causes contributed to the lithium-ion battery fire that grounded Boeing’s 787 Dreamliners last year, according to the final report from the National Transportation Safety Board. Among the cited causes were regulatory and company oversight and certification issues as well as design and testing problems on both Boeing’s part and that of the battery maker, Yuasa.
Overcharging or environmental issues were ruled out as likely factors for the internal battery short circuit that triggered the fire, however no specific issue was found to be to blame. The most likely culprits, according to the report, were contamination or a battery manufacturing process that allowed such defects coupled with a failure on Boeing’s part to understand how the batteries could fail.
For the full report, see “Auxiliary Power Unit Battery Fire Japan Airlines Boeing 787-8, JA829J.”
http://www.ntsb.gov/doclib/reports/2014/AIR1401.pdf
Tomi Engdahl says:
FAA issues lithium battery warning
Keep spares in your hand luggage, airline passengers told
http://www.theregister.co.uk/2015/10/14/faa_lithium_battery_warning/
The Federal Aviation Administration (FAA) has warned US airline passengers not to pack spare lithium batteries in their checked baggage.
The advisory covers “spare lithium metal and spare rechargeable lithium ion batteries for personal electronics such as cameras, cell phones, laptop computers, tablets, watches, calculators, etc”.
The FAA states: “Spare (uninstalled) lithium ion and lithium metal batteries must be carried in carry-on baggage only. When a carry-on bag is checked at the gate or at planeside, all spare lithium batteries must be removed from the bag and kept with the passenger in the aircraft cabin. The battery terminals must be protected from short circuit.”
Tomi Engdahl says:
Lithium-ion batteries prohibits in air cargo
There are several cases where the transported in the hold of aircraft lithium-ion batteries have overheated up to the fire. Now, the UN panel recommends ban on air cargo batteries completely.
Only in October the United Nations opposed the total ban on the carriage.
It is a long-standing dispute. As early as last March, representing the major aircraft manufacturers association announced that the lithium-ion batteries for transport pose a risk, which is not acceptable to aviation. Manufacturers that one battery can ignite flammable entire cargo into the fire, which of course would lead to a major disaster.
In 2014, the world was prepared from 5.4 billion lithium-ion battery. Civil Aviation Organization, ICAO, about 30 per cent of these were transported by air.
Source: http://etn.fi/index.php?option=com_content&view=article&id=3933:litiumioniakkujen-lentorahdit-kielletaan&catid=13&Itemid=101
Tomi Engdahl says:
https://www.schneier.com/blog/archives/2019/08/software_vulner.html
Tomi Engdahl says:
Boeing 787s must be turned off and on every 51 days to prevent ‘misleading data’ being shown to pilots
https://www.theregister.co.uk/2020/04/02/boeing_787_power_cycle_51_days_stale_data/
US air safety bods call it ‘potentially catastrophic’ if reboot directive not implemented
The US Federal Aviation Administration has ordered Boeing 787 operators to switch their aircraft off and on every 51 days to prevent what it called “several potentially catastrophic failure scenarios” – including the crashing of onboard network switches.
The airworthiness directive, due to be enforced from later this month, orders airlines to power-cycle their B787s before the aircraft reaches the specified days of continuous power-on operation.
Tomi Engdahl says:
Boeing suspends 787 airplane production
https://tcrn.ch/34gKRku
Boeing said Monday it will suspend all 787 operations at its South Carolina factory following a stay-at-home order issued by the governor, effectively putting the company’s entire commercial airplane production on hiatus.
Boeing didn’t provide a date when it will restart production of the 787 airplanes or provide guidance on any of its other operations in the U.S.
Tomi Engdahl says:
Boeing 787s Must Be Turned Off and On Every 51 Days To Prevent ‘Misleading Data’ Being Shown To Pilots
https://tech.slashdot.org/story/20/04/02/206230/boeing-787s-must-be-turned-off-and-on-every-51-days-to-prevent-misleading-data-being-shown-to-pilots
Tomi Engdahl says:
Boeing 787s must be turned off and on every 51 days to prevent ‘misleading data’ being shown to pilots
US air safety bods call it ‘potentially catastrophic’ if reboot directive not implemented
https://www.theregister.com/2020/04/02/boeing_787_power_cycle_51_days_stale_data
Tomi Engdahl says:
https://www.engadget.com/2015-05-01-boeing-787-dreamliner-software-bug.html I had to fact-check this one… sorry to say, pretty accurate. -_-
Tomi Engdahl says:
The Insane Engineering of the 787
https://www.youtube.com/watch?v=lapFQl6RezA