Japan Airlines Co., the world’s second-largest operator of Boeing Co. Dreamliners, diverted two of the 787 jets back to their departure airports today after separate problems with the aircraft.

A 787 bound for Tokyo returned to Moscow after electrical issues with the toilet and galley that were unrelated to the battery, said Norihisa Hanyu, a spokesman at the airline. Another Dreamliner headed back to San Diego airport after an indicator showed problems with an engine de-icing system, said Takuya Shimoguchi, another company spokesman.

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Problems with lithium-ion batteries led Japan Airlines and ANA Holdings Inc., operator of the largest fleet of the aircraft, to ground their Dreamliners for more than four months this year. Within two weeks after 787 operations resumed in June, Japan Airlines canceled a Dreamliner flight because of an issue with the engine anti-icing system.

Boeing is aware of the problems and has been working with JAL to fix them, Rob Henderson, a spokesman in Tokyo for the company, said by telephone today.

The flight from San Diego, bound for Tokyo, was able to take off again after maintenance, Shimoguchi said.

Editors: Lena Lee, Garry Smith. To contact the reporter on this story: Chris Cooper in Tokyo at ccooper1@bloomberg.net; Kiyotaka Matsuda in Tokyo at kmatsuda@bloomberg.net. To contact the editor responsible for this story: Anand Krishnamoorthy at anandk@bloomberg.net. 

Photo Credit: Fire trucks surround Japan Airlines Boeing 787 Dreamliner that caught fire at Logan International Airport in Boston. Bryan Snyder / Reuters