Kingman, David, Illumin Article...

David Kingman WRIT 340 Grounding the Boeing 787: What’s going on? Illumin Article

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Abstract

The Boeing 787 Dreamliner was supposed to be one of the most anticipated model

releases in recent aircraft history, with all new engines, a composite material body, an

innovative interior design, and a huge jump in fuel efficiency. However, the 787 has hit

the headlines in recent months due to lithium-ion battery failures and fires, among other

problems, leading to a nationwide grounding of the aircraft by the Federal Aviation

Administration. Investigators still cannot trace the source of the battery problems, leaving

it uncertain when the Dreamliner will be back in the air again, although several solutions

(both temporary and long-term) have been suggested. Recently, the FAA allowed the

Dreamliner to resume flying passengers after Boeing modified and improved the safety

features surrounding the batteries.

What is the 787 Dreamliner?

The new Boeing 787 Dreamliner, shown in Figure 1, is a mid-size aircraft that is meant to

revolutionize the experience of flying. Capable of seating between around 230 to 300

passengers [1], the 787 can fly close to 8,000 nautical miles [2] – that is just more than

enough to fly from Los Angeles to Singapore. Most of the excitement surrounding this

plane comes from the increased fuel efficiency (up to 20% more efficient [3]), quieter

engines, a lightweight composite material body, and an extremely comfortable interior.

By the end of 2012, various airlines had already ordered and purchased a total of 848

units of the Dreamliner [4]. However, one supposedly insignificant change has proven to

be the cause of the worst nightmare for any aircraft company. Recent problems with the

787, mainly due to the new lithium-ion batteries used, have led the FAA (Federal


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Aviation Administration) to ground all units of the Dreamliner until solutions can be

found.

Figure 1: Profile view of the Boeing 787 Dreamliner

http://boeing.mediaroom.com/index.php?s=13&item=1144

What’s so special about it?

CFRP (Carbon Fiber Reinforced Polymer)

One of the biggest (and riskiest) appeals of the 787 Dreamliner is its extensive use of

CFRP, traditionally labeled as simply “carbon fiber”, which will compose about half of

the entire aircraft structure [3]. This incorporation of CFRP will significantly reducing

the total weight of the aircraft. Traditionally, aircraft have been made with aluminum

because of its relatively high strength-to-weight ratio. However, the widespread


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development of CFRP has led to a material that can be even lighter and even stronger

than aluminum [5]. Simply put, CFRP is composed of several different materials (a

composite), mainly carbon fiber sheets that are glued together in layers using resins such

as epoxy. Since carbon fiber sheets are designed to be incredibly strong and withstand

great forces in a single direction (but very weak in all others), multiple sheets can be

glued together in different orientations so that the resultant composite is strong in all

directions [5]. In conjunction with its smaller weight, this creates a material with greater

strength and stiffness per unit mass that surpasses metals [5]. Moreover, since larger

CFRP parts can be made, this eliminates the need for all the nuts and bolts that piece

together metal pieces, further reducing the total weight of the aircraft. However, CFRP

tends to be very expensive due to its manufacturing complexity, especially since it needs

to be custom-designed for the specific application.

Engines

Another attraction of the 787 is the new engines that have been employed, which show

several significant improvements over previous aircraft engines. The Dreamliner comes

with either one of two sets of engines: one by General Electric (GE), and the other by

Rolls-Royce. By employing lighter materials and with finer engine tuning, engineers

were able to improve the overall efficiency of the engines, resulting in 15% less fuel

consumption than the engines of the Boeing 767, all the while reducing undesirable

emissions [6]. In addition, the sawtooth design of the engine cover at the back known as

“chevrons”, as seen in Figure 2, was engineered to reduce noise levels. This not only


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provides a much quieter and comfortable ride for the passengers, but also reduces the

level of noise pollution in areas the 787 flies through.

Figure 2: Saw tooth design of 787 engine cover “chevrons”

http://www.nytimes.com/interactive/business/boeing-‐787-‐dreamliner-‐

timeline.html?ref=business#/#time237_7028

Interior

The difference that the passengers will really notice, however, comes from the all-new

interior design. One of the highlights for passenger comfort is the higher cabin pressure

and higher air humidity. Since most of the plane will be made out of the composite CFRP

material, the plane will be able to withstand 15% humidity (that would cause corrosion in

metal over time) compared to the traditional 4% [7]. The use of CFRP also means that

there is less risk of the aircraft structure wearing out from fatigue over time due to higher


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pressures [7]. Another exciting feature of the interior is the larger, electronically

dimmable windows, as seen in Figure 3. Once again, due to the better structural rigidity

of CFRP compared to aluminum, the windows can be larger without compromising the

strength of the aircraft. Moreover, the “electrochromic dimmable” windows supplied by

PPG Aerospace use a new technology that can vary the transparency of the window

depending on the electric current applied, allowing passengers to choose from five

different transparency settings [8].

Figure 3: The larger, electronically dimmable windows of the 787

http://www.gadling.com/photos/united-‐dreamliner-‐interior/5189013/#5189013

Lithium-ion Batteries

The lithium-ion batteries used in the 787 are manufactured by GS Yuasa, a company

from Japan – they were not built in-house by Boeing [9]. These types of batteries are

commonly used because they have some of the highest energy densities (that is, the most


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energy in the smallest volume), which translates to huge weight savings for a desired

amount of stored energy. This is mainly because lithium is an extremely reactive element,

meaning that its bonds can hold a lot of energy. A lithium-ion battery can hold up to 150

watt-hours per kilogram. In comparison, nickel metal-hydride batteries (NiMH, the

closest competitor) can only store up to 100 watt-hours per kilogram – this means that for

the same mass, lithium-ion batteries are equivalent to 1.5 NiMH batteries [10]. This is a

significant factor in the decision to use lithium-ion batteries, since one of the design goals

of the 787 is to have a strong yet incredibly light plane to improve fuel efficiency. This is

also why lithium-ion batteries are so popular in handheld devices such as phones and

portable music players.

However, there are some significant costs to using lithium-ion batteries. A lithium-ion

battery cannot be used again after being completely drained of its charge – this means a

replacement will have to be made every time a battery gets completely discharged.

Additionally, they degrade much faster at higher temperatures, and so applications are

limited to colder environments (or they would have to be forcibly cooled). More

importantly, if the battery gets hot enough to ignite the electrolytes inside, a fire will

actually start [10]. These very risks may explain the battery-related problems some of the

787 units have been having lately.

What problems came up?

Below is brief timeline of several events and failures of the 787 Dreamliner surrounding

the decision to ground all units [11].


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o January 7 – Battery in a Japan Airlines (JAL) unit overheated and caught fire at

Boston’s Logan International Airport

o January 8 – Fuel leaks from a different JAL unit

o January 9 – A problem with the wiring in same area as battery fire from the JAL

unit is found in a United Airlines unit

o January 11 – Another fuel leak is reported a different JAL unit

o January 13 – The same JAL plane that leaked fuel on January 8 leaks more fuel

from different valves

o January 16 – An All Nippon Airways (ANA) unit displays a false computer

warning about smoke inside one of the electrical compartments, leading to an

emergency landing and evacuation (see Figure 4)

o January 16 – JAL and ANA voluntarily ground all their 787s

o January 16 – FAA announce their decision to ground all 787s of US-based

airlines

In summary, there were several incidents of fuel leaks, a battery that caught fire (shown

in Figure 4), and problems with wiring around the batteries on different planes that

consequently led the FAA to ground all the US-based 787s. Since then, airlines and

administrations in other countries have followed suit and grounded their 787s (including

Chile’s Directorate General of Civil Aviation, India’s Directorate General of Civil

Aviation, and European Aviation Safety Agency) [11].


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Figure 4: Burnt and un-‐burnt batteries from ANA 787

http://news.yahoo.com/photos/burnt-‐auxiliary-‐power-‐unit-‐battery-‐removed-‐nippon-‐airways-‐photo-‐

103834934.html

How did these problems come about?

There are really two concerns as a result of the recent grounding of 787s: what exactly

caused the battery failures, and how the FAA or Boeing could let this happen. As you

would expect from one of the biggest commercial airplane companies in the world,

Boeing put the 787 under various rigorous tests, including extreme weather conditions

[12] and 1000 hours of test flights [13], under which no problems regarding the battery

came up. However, the purpose of most of these tests was to investigate the strength and

durability of the new composite body design of the 787, which was the primary concern

during the aircraft’s development. As such, the batteries were overlooked when it came to

testing. But why were these so neglected? As it turns out, the FAA actually outsourced

most of the inspection to Boeing employees themselves, a trend that has become more


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common over the past decade [14]. While no employee would certify anything that they

were certain would fail, this delegation of responsibility can mean that inspections will

not be as strict.

As for the batteries themselves, Boeing, the FAA, and the US NTSB (National

Transportation Safety Board) are still exploring the exact reasons the batteries overheated

and caught fire [15]. So far, investigations have only revealed that the battery that caught

fire had some short-circuiting and uncontrolled heating, and investigators are still

stumped about the true cause of the failures [16]. Additionally, several systems that were

designed to prevent the batteries from setting on fire actually failed to work [17]. What

must be understood, though, is that when lithium-ion batteries have manufacturing

defects or are damaged, it is possible for them to short circuit and catch fire. An even

larger consequence of lithium-ion battery fires is that temperatures can reach up to 1,100

degrees Fahrenheit, nearly enough to melt the aluminum used in most airplanes [17].

Finally, when trying to recharge an already low-charged lithium-ion battery, it may be

unable to accept the charge, and so the energy is dissipated as heat and could cause the

battery to ignite [18].

What can be done?

One of the ideas Boeing has supposedly come up with to temporarily eliminate the threat

of combusting batteries is to place them inside containment boxes [16]. In the case of a

battery failing and catching fire, this would both protect the nearby equipment (and rest

of the plane) while venting the smoke overboard.


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There have also been two other suggestions by Dr. Donald Sadoway, a Chemistry

professor from MIT [19]. One of his suggestions is to replace the battery system entirely

by switching from the lithium-ion batteries to nickel metal-hydride batteries, as these

have shown to be a safer alternative. NiMH batteries are a rather recent development, and

so were not yet an option when the 787 was still being developed. The problem with

switching to NiMH batteries, however, lie in its larger weight (a key factor in decisions

for the 787), and designing the new battery system as well as the necessary certification

process could take up to a year (therefore leaving 787s grounded for even longer).

Another issue is that NiMH batteries tend to lose their maximum charge faster than

lithium-ion batteries (20% charge loss per month compared to lithium-ion’s 5%) [10].

This means that NiMH batteries would have to be replaced more frequently if Boeing

decides to make the switch.

Sadoway’s other more immediate solution is to improve the ventilation and temperature

detection system of the current lithium-ion batteries. This would improve the heat

dissipation of the battery (reducing the overall temperature and possibility of catching

fire), as well as ensuring that the temperature of the batteries says within a safe range

during flight [19]. By the end of January, Boeing requested the FAA to allow them to

resume test flights of the 787 to further examine the lithium-ion batteries while the other

787s are still grounded [19].

What now?


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As of the end of April, Boeing and the FAA were still not able to find the cause of the

battery problem [20]. However, the FAA did approve a plan by Boeing to modify the

safety system surrounding the battery, which significantly reduces the risk of battery

fires. The battery is now installed in a stainless steel box that vents the hot air directly

outside the plane [20], and an ALL Nippon Airways unit was the first to receive the

retrofit. While the Boeing 787 Dreamliner is once again allowed to carry passengers and

resume flights, it is important for both the physical safety as well as confidence of airlines

and passengers for Boeing and the FAA to continue researching the cause of the battery

fires and to make the appropriate amends.

References

[1] Boeing. (2012, Oct.). Airplane description. Boeing. WA. [Online]. Available:

http://www.boeing.com/commercial/airports/acaps/787sec2.pdf

[2] J. Ostrower (2009, May 7). Boeing confirms 787 weight issues. Flight International.

[Online]. Available: http://www.flightglobal.com/news/articles/boeing-confirms-787-

weight-issues-326087/

[3] R. Waugh (2011, Sept. 26). Not just a load of hot air: Dream becomes reality as

Boeing’s new carbon-fibre 787 Dreamliner heralds a new age of air travel. Daily Mail.

[Online]. Available: http://www.dailymail.co.uk/sciencetech/article-2041863/Boeing-

787-Dreamliner-reality-carbon-fibre-plane-delivered-Japan.html#axzz2K5z9OQii

[4] Boeing. (2012, Dec.). Orders and deliveries. Boeing. WA. [Online]. Available:

http://active.boeing.com/commercial/orders/index.cfm?content=displaystandardreport.cf

m&RequestTimeout=500&optReportType=AnnOrd&pageid=m15521


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[5] T. Johnson (2013). Understanding CFRP composites: The amazing capabilities of

carbon fiber reinforced polymers. About.com. [Online]. Available:

http://composite.about.com/od/aboutcarbon/a/Understanding-Cfrp-Composites.htm

[6] S. F. Clark (2012). 787 Propulsion system. Boeing. [Online]. Available:

http://www.boeing.com/commercial/aeromagazine/articles/2012_q3/2/

[7] M. Adams (2006, Nov. 1). Dreamliner designed so fliers can breathe easy. USA

Today. [Online]. Available: http://usatoday30.usatoday.com/money/biztravel/2006-10-

30-boeing-air-usat_x.htm

[8] Flight Global (2005, Dec. 20). Qantas deal sees launch of 787-9. Flight International.

[Online]. Available: http://www.flightglobal.com/news/articles/qantas-deal-sees-launch-

of-787-9-203644/

[9] C. Cooper, & K. Matsuda (2013, Feb. 6). Boeing 787 battery maker to maintain

output amid probe. Bloomberg. [Online]. Available:

http://www.bloomberg.com/news/2013-02-05/boeing-787-dreamliner-battery-maker-gs-

yuasa-s-profit-declines.html

[10] M. Brain (2006, Nov. 14). How lithium-ion batteries work. HowStuffWorks.

[Online]. Available: http://electronics.howstuffworks.com/everyday-tech/lithium-ion-

battery.htm

[11] CBC News (2013, Feb. 22). Timeline: The Boeing 787 Dreamliner. CBC News.

[Online]. Available: http://www.cbc.ca/news/interactives/boeing787-timeline/

[12] L. Gunter (2012, Apr. 22). 787 Dreamliner undergoing extreme-weather testing in

Florida. Boeing. [Online]. Available:

http://boeing.mediaroom.com/index.php?s=43&item=1179


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[13] L. Gunter (2012, June 17). Boeing 787 Dreamliner passes 1,000 hours of flying.

Boeing. [Online]. Available: http://boeing.mediaroom.com/index.php?s=43&item=1268

[14] K. M. Song (2013, Feb. 4). FAA faulted for outsourcing 787 safety checks to

Boeing. Seattle Times. [Online]. Available:

http://seattletimes.com/html/localnews/2020288737_787faaxml.html

[15] A. Shalal-Esa (2013, Feb 1). Boeing 787 investigation making progress: NTSB.

Yahoo News. [Online]. Available: http://news.yahoo.com/boeing-787-investigation-

making-progress-ntsb-001031344--finance.html

[16] MarketWatch (2013, Feb. 4). Boeing 787 problems still stump investigators.

MarketWatch. [Online]. Available: http://www.marketwatch.com/story/boeing-787-

problems-still-stump-investigators-2013-02-04

[17] J. Lowy (2013, Feb. 3). Rule reversal: Boeing 787 grounded, but batteries can fly.

KOMOnews. [Online]. Available: http://www.komonews.com/news/boeing/787-

grounded-but-batteries-can-fly-under-new-rules-189565481.html

[18] C. Drew, H. Tabuchi, & J. Mouawad (2013, Jan 29). Boeing 787 battery was a

concern before failure. NY Times. [Online]. Available:

http://www.nytimes.com/2013/01/30/business/boeing-aware-of-battery-ills-before-the-

fires.html?pagewanted=all&_r=1&

[19] S. Musil (2013, Jan. 27). Boeing battery solution may keep 787 grounded until 2014.

CNET. [Online]. Available: http://news.cnet.com/8301-11386_3-57566066-76/boeing-

battery-solution-may-keep-787-grounded-until-2014/


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[20] J. Paur (2013, Apr. 29). Boeing 787 Dreamliner Finally Resumes Passenger Flights.

Wired. [Online]. Available: http://www.wired.com/autopia/2013/04/boeing-787-

dreamliner-resumes-passenger-flights/

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