{"id":9002,"date":"2014-06-12T13:10:23","date_gmt":"2014-06-12T20:10:23","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=9002"},"modified":"2014-06-12T13:10:23","modified_gmt":"2014-06-12T20:10:23","slug":"ntsb-releases-initial-report-recommendations-dreamliner-battery-fires","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/ntsb-releases-initial-report-recommendations-dreamliner-battery-fires\/","title":{"rendered":"NTSB Releases Initial Report, Recommendations on Dreamliner Battery Fires"},"content":{"rendered":"

January 2013 was a time of great concern for operators of the Boeing 787 \u201cDreamliner.\u201d On the 7th, an empty 787 operated by Japan Airlines experienced a fire in the main battery pack.\u00a0 On the 16th, an All Nippon Airways 787 made an emergency landing and evacuated everyone on board on emergency slides after the flight crew responded to a computer warning of smoke inside one of the electrical compartments. \u00a0Other incidents pointed to issues in the use and transport of lithium-ion batteries such as those used in the big Boeing.<\/span><\/p>\n

\"Locations<\/a>

Locations of main battery, APU (auxiliary power unit) batteries on 787<\/p><\/div>\n

The National Transportation Safety Board (NTSB) has directed several recommendations to the Federal Aviation Administration (FAA), derived from the agency\u2019s ongoing investigation of the Japan Airlines incident only, at this time.\u00a0 Certainly the ongoing investigation of the All Nippon flight incident will merit a separate report.<\/p>\n

Despite the fact that many industry \u201cinsiders\u201d have offered opinions as to how Boeing should have designed and constructed the two lithium-ion battery packs in their new airliner, the NTSB letter, from Acting Chairman Christopher A. Hart to FAA Administrator Michael P. Huerta \u00a0probably has the most disinterested and objective approach to the issue.<\/p>\n

In what is an international collaboration, representatives from Boeing<\/a>, the FAA, the Japan Transport Safety Bureau, the French BEA, and technical advisors from Japan and France participated in the investigation, according to Aviation Week<\/i><\/a>.\u00a0 The magazine included Japan-based GS Yuasa<\/a>, which builds the batteries, and Thales<\/a>\u00a0which builds the charging system.<\/p>\n

\"NTSB<\/a>

NTSB investigator Mike Bauer examines aftermath of main battery fire<\/p><\/div>\n

The New York Times<\/em> reported<\/a> on the two-day hearing the NTSB oversaw a year ago in April.\u00a0 \u201c\u2019We are here to understand why the 787 experienced unexpected battery failures following a design program led by one of the world\u2019s leading manufacturers and a certification process that is well-respected throughout the international aviation community\u2019 Deborah A. P. Hersman, the board\u2019s chairwoman, said.<\/p>\n

\u201c[Mike Sinnet, Boeing’s chief engineer on the 787 \u00a0said the failure calculation was based on data provided by GS Yuasa. \u2018That value essentially is reached by experience with similar type cells,\u2019 he said. \u2018GS Yuasa had experience with over 14,000 cells of similar makeup. They had millions upon millions of those cells without any cell venting.\u2019<\/p>\n

\"NTSB's<\/a>

NTSB’s recommended changes to internal structure of 787 battery packs. Note venting previously lacking<\/p><\/div>\n

\u201cOne of the tests consisted of driving a nail into a battery cell to provoke a short circuit. While the cell failed, the test did not result in a fire. But under repeated questioning, Mr. Sinnett acknowledged that the nail test had been inadequate and was not \u2018conservative enough.\u2019 Boeing, he said, found that the batteries could catch fire only if they were overcharged.\u201d<\/p>\n

Based on the hearings and input from the major players involved, the NTSB released a 12-page letter to the FAA<\/a> last month, with a series of recommendations for preventing the types of fires experienced on the 787.\u00a0 In carefully worded form, the letter avoids finger pointing, but does seem to question the thoroughness of the manufacturers involved in the battery and electrical control systems in their initial testing of those systems.<\/p>\n

Therefore, the National Transportation Safety Board makes the following\u00a0<\/em>recommendations to the Federal Aviation Administration:<\/em><\/p>\n

Develop abuse tests that subject a single cell within a permanently installed,\u00a0<\/em>rechargeable lithium-ion battery to thermal runaway and demonstrate that the\u00a0<\/em>battery installation mitigates all hazardous effects of propagation to other cells\u00a0<\/em>and the release of electrolyte, fire, or explosive debris outside the battery case.<\/em><\/p>\n

The tests should replicate the battery installation on the aircraft and be conducted\u00a0<\/em>under conditions that produce the most severe outcome. (A-14-032)<\/em><\/p>\n

After Safety Recommendation A-14-032 has been completed, require aircraft\u00a0<\/em>manufacturers to perform the tests and demonstrate acceptable performance as\u00a0<\/em>part of the certification of any new aircraft design that incorporates a permanently\u00a0<\/em>installed, rechargeable lithium-ion battery. (A-14-033)<\/em><\/p>\n

Work with lithium-ion battery technology experts from government and test\u00a0<\/em>standards organizations, including US national laboratories, to develop guidance\u00a0<\/em>on acceptable methods to induce thermal runaway that most reliably simulate cell\u00a0<\/em>internal short-circuiting hazards at the cell, battery, and aircraft levels. (A-14-034)<\/em><\/p>\n

Review the methods of compliance used to certify permanently installed,\u00a0<\/em>rechargeable lithium-ion batteries on in-service aircraft and require additional\u00a0<\/em>testing, if needed, to ensure that the battery design and installation adequately\u00a0<\/em>protects against all adverse effects of a cell thermal runaway. (A-14-035)<\/em><\/p>\n

Develop a policy to establish, when practicable, a panel of independent technical\u00a0<\/em>experts to advise on methods of compliance and best practices for certifying the\u00a0<\/em>safety of new technology to be used on new or existing aircraft. The panel should\u00a0<\/em>be established as early as possible in the certification program to ensure that the\u00a0<\/em>most current research and information related to the technology could be\u00a0<\/em>incorporated during the program. (A-14-036)<\/em><\/p>\n

NTSB Acting Chairman Hart concluded, \u201cThe history of commercial aviation is one in which emerging technologies have played a key role in enhancing flight safety.\u00a0 This is why it\u2019s crucial that the process by which these technologies are evaluated and certified is as robust and thorough as possible. These recommendations will take us further in that direction.\u201d<\/p>\n

The NTSB is expected to issue its final report on the fire investigation in the fall.<\/p>\n

All of the information the NTSB has released for this investigation so far can be accessed here<\/a>. \u00a0 All recommendations are of interest to anyone anticipating designing or constructing an electrically-powered aircraft.<\/p>\n

Considering the collective experience of the bodies involved, and the real-world daily expansion of the database being collected, we can anticipate fewer such incidents despite growing use of these batteries.\u00a0 Exploration of non-flammable electrolytes and more assured means of preventing and containing any such incidents will lead to safer aircraft for the flying public.<\/p>\n