Safety board raises new concerns over jetliner batteries

Federal safety investigators before being approved for use in the sky "most serious consequences " through rigorous testing that should produce energy systems in commercial, new concerns about the use of lithium-ion batteries to launch aircraft.
Boeing 787 Dreamliner continues investigating lithium-ion secondary battery as the National Transportation Safety Board issued recommendations on Thursday .
Aircraft self- cities last year , the first two batteries on airplanes.
Federal Aviation Administration and Boeing Dreamliner has endorsed the safety of battery system redesign . The NTSB said the change is consistent with the new recommendations.
But the safety board , which will have the effect of FAA regulations for aircraft battery in 2008 , the need to correct .
The batteries on airplanes are much resemble the conditions to be tested , said the safety board .
They are cells that are damaged intentionally " second test " should be tolerated. They should be tested so that produce " the most serious consequences . "
Adjacent cells - or cascade - This type of test batteries thermal runaway , the temperature and pressure that can promote the growth of a violent experience may show that .
Thermal runaway is usually smoked , FAA approved Dreamliner battery resulting in a known concern . But the smoke was thought to be rare, and engineers to design ways to vent the smoke.
But a small , 3-inch flame spewing molten wax-like material from the battery box and " dense smoke ," a witness described the incident battery Dreamliner
Aircraft manufacturers to ensure that the system will protect " against adverse effects. "
"They are designed to prevent accidents and save lives, the NTSB is vitally interested in these recommendations," the board wrote in a letter to FAA Administrator Michael Huerta.
Dreamliner and its auxiliary power unit , original battery , or permanently installed for lithium- ion batteries for use APU is the first large commercial airplane . They are small, lightweight and powerful, because batteries are valuable .
NTSB seeking certification in the battery, the battery maker GS Yuasa Corporation Boeing and Kyoto in Japan, a " smoke " will occur in approximately says that " less than one in 10 million flight hours. "
But the commercial flight after 51,662 hours , culminating in a fire in one of the two batteries failed.
The first incident , a maintenance worker on January 7, 2013 , Japan Airlines at Logan Airport in Boston Dreamliner Park entered the bay of e stern and heavy smoke coming from the battery box in a small flame 3 inches.
Auxiliary power unit lithium -ion battery airplane, or the power of the APU can be supplied . The incident is still under investigation , eight-cell battery of the NTSB , a short circuit, resulting in a thermal runaway , the expansion and damage adjacent cells .
Nine days later, on a flight of All Nippon Airways in the Dreamliner in Japan during main battery failed. No fire was observed , and the damage was limited to the battery casing .
" This failure of the Boeing 787 as part of the certification process is carried out on the basis of the evidence and analysis .... not expected," the NTSB wrote .
In a 2006 essay , the manufacturer battery damage , smoke , fire and damage the battery box to see if battery is involved in an internal short circuit in one of the cells eight occurred in a steel pin . Damaged cells emit smoke , tests showed , but the smoke can be managed effectively by the ventilation system of the aircraft.
FAA and Boeing were loaded into a cell or battery thermal runaway can occur only in the confidence to say that. And they, taking steps to protect against overcharging and smoke ventilation precautions taken .
Boeing is a single cell, a short circuit will cause the smoke was thought to be possible, but is an effect of thermal runaway " underestimated " .
Cause thermal runaway in batteries that test the safety board is concerned about the repeatability and researchers in testing methods current practical failure " observed reliably produce the effects may not be as serious as the failure " Found said .
Internal shorts , the Security Council , he said, is difficult to reproduce . But it is important that security solutions , said.
A spokesman for the safety board , it is likely that its final report later this year , subject to the recommendations of the Board may also told CNN