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Boeing Co's 787 Dreamliner, poised to resume flights after a more than three-month hiatus, is safe even while the cause of a battery defect remains uncertain, the aircraft manufacturer said.
The planes have been prevented from flying worldwide since January 16 after lithium-ion batteries on two separate planes overheated and melted, leading to the longest grounding of a large commercial aircraft by US and Japan regulators since jets were introduced in the 1950s.
Boeing won approval from the FAA for the 787’s redesigned battery system last week. Stress testing showed temperatures in the new structure dropped quickly after reaching a maximum of 130 degrees Celsius (266 degrees Fahrenheit), compared with 300 degrees Celsius sustained for 30 minutes previously, Mike Sinnett, vice-president and chief project engineer of the 787 program, told reporters in Tokyo today.
“Even if we never know the root cause, the enclosure keeps airplanes safe, and eliminates the possibility of fire,” Sinnet said. “I can’t comment on the root cause because the investigation is on-going.”
The Japanese government also approved the restart of 787 flights, the Transport Ministry said yesterday. The permission will be for all flights, including test and commercial services, according to Shigeru Takano, a director at the ministry’s Civil Aviation Bureau.
ANA, JAL
Boeing has about 300 personnel on 10 teams to install the fix on airlines. Tokyo-based ANA, with 17 Dreamliners, started repairs earlier this week on five of its planes at four airports around Japan, according to Ryosei Nomura, a spokesman. Japan Airlines Co also started upgrading the batteries, Hisanori Iizuka, a spokesman at the carrier, said yesterday.
Chicago-based Boeing’s reworked battery includes more protection around the cells to contain overheating, a steel case to prevent any fire from spreading and a tube that vents fumes outside the fuselage. ANA and JAL additionally have put in place a system to monitor the batteries during flights and transmit data to the ground, the carrier said yesterday.
The cost for replacing the battery will be about $465,000 a plane in the US, according to the FAA and the fix adds about 150 pounds of weight to a 787.
Neither the FAA nor the NTSB has determined what caused the battery faults that sparked a January 7 fire on a JAL 787 in Boston and forced an emergency landing by an ANA jet in Japan nine days later.
