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Cause and Actions
- What caused the battery problems? Can Boeing's modification plan which was decided during the investigations be considered effective measures to prevent recurrent of similar battery problems?
- Measures for every probable cause have been implemented. Therefore, when the Japan Transport Safety Board eventually pinpoints what caused the events of JAL and another Japanese operator, all necessary measures will have already been completed. Extra safeguards have been added to prevent battery problems caused by unforeseen causes. Therefore, we feel the measures are sufficient to preclude occurrence of similar incidents. The two events of JAL and another Japanese operator remain under investigation by U.S. and Japanese aviation investigative agencies.
- Measures have not been implemented for about 20 of the 100 or so causes, as they were identified as "theoretically possible, but realistically impossible." Are you sure that it is safe?
- For example, causes which could not have led to battery problems were excluded, such as overheating of the cell due to external flames. Overcharge was also excluded, as multiple measures have already been implemented to correct this, and they have been validated as functioning properly as a result of flight data analyses of the events of JAL and another Japanese operator.
- You mentioned that JAL's comments and requests are reflected in Boeing's modification plan. What do you mean?
- For example, we requested corrective actions to eliminate the root cause that triggered the battery failure, such as measures to prevent overheating, in addition to measures to eliminate each cause, such as the enclosure system to prevent smoke from flowing into the cabin.
- What is JAL's view on Boeing's modification plan?
- The measures cover all probable causes and reflect requests from the standpoint of an operator as well as the aircraft manufacturer. Therefore, we determined that implementation of the measures contained in the modification plan would ensure the safe operation of the 787.
- Isn't it possible that there are other causes besides the battery itself?
- Of the 100 or so probable causes identified by Boeing, short-circuits caused by electric currents flowing from the battery exterior and overcharge were considered. But as a result of analyses of the events concerning JAL and another Japanese operator, it was determined that these phenomena were not the cause of the battery failures.
- You mentioned that batteries are not normally used during flight. Then why did they overheat in the events of JAL and another Japanese operator?
- Power from the batteries is not used in flight, but the batteries are always connected to the aircraft, and if voltage falls, the battery is recharged. However, when government investigative agencies analyzed the flight data of JAL and another Japanese operator, they assessed that the battery was almost fully charged when the battery failure happened. Investigations into cause of the battery failure in flight and smoke remain in progress.
- You mentioned that the battery is enclosed in a sealed container so that it would not be affected by fire or smoke erupting from the battery. Shouldn't you take basis steps to avoid fire or smoke in the first place?
- In our modification work, we implemented measures for 18 factors to prevent fire or heat from erupting from the battery. Therefore, these measures eliminate the root cause. Enclosing the battery was added as an extra safeguard in an unlikely event of a battery failure.
- Couldn't you have replaced lithium-ion batteries with nickel-cadmium batteries, which are normally used on aircraft?
- Lithium-ion batteries were chosen after a careful review by Boeing of all available alternatives because they best met the performance and design objectives of the 787. According to Boeing, lithium-ion batteries are the best because they generate large amounts of electric power in short period of time. As the safety of lithium-ion batteries is equivalent to that of nickel-cadmium batteries, Boeing has no plans to replace lithium-ion batteries with nickel-cadmium batteries.
- Lithium-ion batteries cannot be checked in as baggage. Is it safe to load and use them as batteries aboard aircraft?
- Generally, lithium-ion batteries are designed with safety considerations, and multiple protective measures are implemented to prevent trouble. They are safe as long as they are used in the environment and under conditions specified by instruction manuals, etc. Likewise, the lithium-ion batteries aboard the 787 have been given multiple layers of protective measures through the specified modification work, and the recurrence of battery problems has been prevented. Lithium-ion batteries can be carried onboard in hand baggage as long as our regulations on volume and piece are observed, but they are forbidden in checked baggage. This is a precautionary measure, as we cannot immediately deal with trouble in the cargo compartment in flight.
- If flight crewmembers detect battery malfunction, how will they respond?
- Even if smoke erupts from batteries in flight, flight crew can continue flying safely without the need for any special operation. By using the modified battery, any fumes from the battery will be enclosed and vented outside the airplane through a tube, and will not spread into the cabin. Also, any potential for fire is eliminated as the battery is enclosed in sealed stainless steel.
- If a battery failed on a route with long flight time, such as transpacific flights or flights to Europe, how would flight crews deal with the problem?
- Even if it were a long distance route, flight crew would not need to execute any special operations in flight. Even in the event of a battery failure, the aircraft can continue flying safely to its destination, as power is normally supplied from the generators in flight. Even if smoke erupts from the battery, it will not affect other systems as the battery is enclosed in a heat-resistant enclosure, and the smoke will be vented outside the aircraft.
- Fire broke out from a lithium-ion battery loaded on a car. Is it the same incident as that aboard the 787?
- As we are unable to check details of this car incident, we cannot assess whether it is similar to our battery problem. There are similarities in terms of lithium-ion battery and cells made in Japan, but we are aware that design standards for aircraft and automobiles differ. Measures to correct all probable causes have been implemented, and we feel that safe operations of the 787 are ensured, despite what may have caused the battery trouble on the car.
- Did you ask battery specialists for their comments on these measures?
- Boeing's project team asked non-interest third parties for their comments, such as universities and national research institutes, and reflected their comments in their corrective actions, which is the approach adopted by the National Aeronautics and Space Administration (NASA) in similar incidents. Likewise, the Japanese Ministry of Land, Infrastructure, Transport and Tourism, Civil Aviation Bureau asked universities and research institutes in Japan for their comments. JAL received advice from Japanese battery manufacturers, which was helpful in confirming that the corrective actions were effective.
- Did you take steps to prevent other malfunctions besides battery problems, such as brake malfunctioning or fuel leaks?
We took various steps to prevent recurrence of past malfunctions, and operated confirmation flights of the 787 to verify they are effective. Customers can feel confident when they fly on JAL's 787.
Fuel leak from left engine during taxiing (January 8, 2013 at JAL)
(1)The check valve to prevent reverse fuel flow opened temporarily;
(2)The fuel valve joining the center fuel tank and left engine fuel tank opened temporarily.
(1)Maintenance staff will activate the center tank fuel pump prior to each flight, and check that there is no unintended fuel flow;
(2)Flight crew were reminded to follow procedures in the manual, in the event of unintended fuel flow during flight.
Cockpit window on Captain's side cracks in flight(January 11, 2013, case of another Japanese operator)
(1)Production quality of antifog film, etc.(details under investigation)
General inspection of soundness of cockpit windows of all aircraft
Fuel leak from left engine during maintenance (January 13, 2013, at JAL)
Insulating adhesive and foreign substance were affixed to parts inside fuel valve actuator.
Procedures were added to visually confirm the valve is closed, after performing an open/close inspection.
- I don't understand the relationship between the U.S. and Japanese civil aviation authorities and government investigative agencies, or the approval process.
- On January 17, 2013 (Japan time), U.S. and Japanese civil aviation authorities issued a notice ordering the suspension of 787 operations (Airworthiness Directive). It instructed that operations of the 787 must not be resumed until the battery is modified as instructed by the civil aviation authority. (It did not, however, mention the actual modifications required.) Boeing issued a modification instruction letter to improve safety of the battery system aboard the 787, and as the modifications conformed to the law and ensured safety, it was approved by the U.S. Department of Transportation, Federal Aviation Administration. Thereafter, U.S. and Japanese civil aviation authorities revised the Airworthiness Directive of January 17, and clearly indicated Boeing's modification instruction letter number as the specific modification work to be performed to resume operations. As a result, implementation of modification work in Boeing's modification instruction letter enabled us to resume operations.
Japan Civil Aviation Bureau (JCAB)
The supervisory government agency for aviation administration of Japan.
Establishes permits and license, safety standards, conducts on-site safety inspections, etc. Issues flying suspension orders, airworthiness directives (TCD), such as approval to resume operations.
U.S. Federal Aviation Administration (FAA)
The supervisory government agency for aviation administration of the U.S.
Establishes permits and license, safety standards, conducts on-site safety inspections, etc. Issues flying suspension orders, airworthiness directives (AD), such as approval to resume operations.
Japan Transport Safety Board (JTSB)
The accident investigative agency of Japan (in charge of aviation, railways, shipping accidents)
An agency of the Ministry of Land, Infrastructure, Transport and Tourism of Japan, but to maintain neutrality, it is independent from the JCAB.
U.S. National Transport Safety Board (NTSB)
Accident investigative agency of the U.S. (in charge of aviation, railways, shipping, pipeline accidents)
To maintain neutrality, it is independent from the U.S. Department of Transportation and under the direct supervision of the President.
Service Bulletin (SB)
A modification instruction letter issued by Boeing, Air Bus, and manufacturers of components.
Gives instructions on modifications and inspections to recover safety of aircraft and components, and reduce failures. The approval of FAA is necessary to issue a SB, depending on its content. Work cannot be performed unless it is approved. Through an agreement with FAA, an FAA-approved SB is approved by JCAB in Japan as it is.
Airworthiness Directive (AD)
If the civil aviation authority determines that modification or inspections are needed to ensure safety of an aircraft or components, it issues an AD to the owner of the aircraft. The aircraft owner has a legal responsibility to follow the directive, otherwise it will be penalized.
An airworthiness directive issued by JCAB is called TCD, and is applied to Japanese national aircraft.
(*)They say that TCD stands for Technical Circular Directive, but the formal English translation used by JCAB is Airworthiness Directive.
An Airworthiness Directive issued by FAA is call an AD (Airworthiness Directive) and is applied to American national aircraft.