Japan Carriers Find No 787 Problems TOKYO - All Nippon Airways and Japan Airlines, the world's biggest operators of Boeing's 787 Dreamliner, said Tuesday that they had completed emergency checks on their fleet and found no threats to safety following a fire aboard a parked 787 jet at London's Heathrow Airport last week. British safety investigators are examining whether a malfunction in an emergency locator transmitter, or any other equipment in the rear of the parked Ethiopian Airlines plane, was behind Friday's fire. The fire, which caused no injuries, nevertheless came as an unwelcome reminder of the overheating lithium-ion batteries that prompted a worldwide grounding of 787 jets earlier this year. The transmitter under scrutiny, which would send out the plane's location after a crash, is powered by a smaller, lithium-manganese battery. Britain's Air Accidents Investigation Branch has said it has essentially ruled out that the larger lithium-ion ones played a role in the fire, but officials have not yet released any other findings. All Nippon, which operates 20 Dreamliners, said it had completed checks on the rear sections of the jets, removing ceiling panels in that area and making sure that all wiring was properly hooked up. It also looked for signs of any charring and other abnormalities on the emergency locator transmitter, and found nothing amiss. The airline carried out the checks on Sunday and Monday, said Megumi Tezuka, an All Nippon spokeswoman based in Tokyo. All Nippon had decided to carry out the inspections voluntarily even though it had not received any specific instructions or guidance to do so from Boeing or regulators here, she said. "In light of the damage on the Ethiopian jet, we carried out voluntary visual inspections of the rear part of the plane from the inside," Ms. Tezuka said. "We found nothing that would prompt us to ground the planes or take any other action for now," she said. The airline was awaiting further information from British investigators and Boeing on the cause of Friday's fire, she added, and would continue to re-evaluate the situation. Japan Airlines, which operates eight Dreamliners, said it had also completed voluntary checks on those planes over a long holiday weekend here in Japan, emphasizing visual checks on the rear part of the fuselage. The airline said that, like All Nippon, it continued to operate 787s as normal on both and international flights. "We remain in close contact with Boeing and are waiting to receiving further information," said the Japan Airlines spokesman, Hisanori Iizuka. The two Japanese airlines together own about half of the Dreamliners delivered so far. But in January, fire broke out aboard a parked Japan Airlines jet, and smoke triggered an All Nippon flight to make an emergency landing, both incidents blamed on the plane's lithium-ion batteries. Those batteries, used in a major commercial airplane for the first time, supply power when the jet is on the ground and provide backup power for the flight systems when it is in the air. The incidents prompted regulators around the world to ground the Dreamliner jets, while Boeing engineers scrambled to find the cause of the overheating, as well as a fix that would prevent future fires. They failed to pin down a cause, but came up with a series of fixes to the batteries that it said made them more fireproof. Flights resumed in late April. The lithium-manganese battery in the transmitter linked to Friday's fire is much smaller and less flammable. Any indication that the transmitter is to blame would be somewhat of a relief for Boeing, because it is used in many passenger and business jets and is not a specific feature of the new 787. Christopher Drew contributed reporting from New York.