All Nippon Airways Co., the biggest operator of Boeing Co.’s 787 passenger jet, canceled a flight today in Japan, citing a problem with the computer controlling the brake system, media outlets reported.

The carrier had several computer problems with the 787 after taking delivery of the first Dreamliner jet in September 2011 and updated a software system last year, ANA spokeswoman Megumi Tezuka said told Bloomberg News.

The ANA cancellation comes as Boeing and federal safety officials are trying to establish the causes for at least two 787 mishaps that have cropped up this week: a fuel leak and an electrical fire on two different planes owned by Japan Airlines. Both incidents took place in Boston’s Logan International Airport.

Boeing said Wednesday it has “complete confidence” in the 787, which is made mostly from lightweight composite materials. The company is ramping up plans to double production of the jet at its Everett, Wash., and North Charleston plants this year to help fill an 800-order backlog.

The National Transportation Safety Board is investigating Monday’s fire. The blaze caused “severe” damage near a battery rack in an electronics bay, the agency said Tuesday. The Federal Aviation Administration is looking into Wednesday’s fuel leak.

Both of the affected planes were made in Everett.

“Unfortunately the aircraft is known now for its problems, not for the performance it delivers and the enhanced safety features,” said Michel Merluzeau, an analyst with G2 Solutions in Kirkland, Wash., told Bloomberg News.

Airlines played down 787 safety concerns, with Qatar Airways’ CEO dismissing recent mishaps as “teething problems,” according to a report by CNBC.com and Reuters news service.

Qatar Airways has five 787s and is Boeing’s largest customer of the Dreamliner in the Middle East with an order for up to 60 of the planes.

“Of course there will be teething problems from time to time, but this is foreseen with any new aircraft program,” Qatar Airways’ Akbar al-Baker said today.

Bloomberg also reported that United Continental Holdings scrapped the inbound and outbound Los Angeles-Tokyo flights on Monday that were to have been flown on a 787. The report cited an airline spokesman, who declined to say why the flights were canceled. Passengers were switched to a different type of plane, and the 787 was to be back in service Tuesday.