Boeing’s chief project engineer for the 787 Dreamliner said the aircraft manufacturer has "extreme confidence" in the passenger jet, despite three incidents this week.

Mike Sinnett told journalists on a conference call Wednesday that the performance of the Dreamliner was roughly similar to the 777 model during its first year in service.

"Just like any new airplane program, we work through … issues and we move on," Sinnett said.

"So while we're happy with the level of the performance of the airplane, we're not satisfied until our reliability and our performance is 100 per cent."

Boeing on Wednesday suffered a third incident in as many days involving the 787, raising safety concerns with the new aircraft.

All Nippon Airways said it cancelled a Dreamliner flight to Tokyo from western Japan because of brake problems.

On Tuesday, a Japan Airlines 787 at Boston’s Logan International Airport had to be towed back to the gate after spilling 150 litres of jet fuel.

Also Tuesday, Boeing confirmed that the fire aboard a Japan Airlines plane on Monday appeared to have started in a battery pack for the plane's auxiliary power unit.

The U.S. National Transportation Safety Board, which opened an investigation into the fire yesterday, described the fire damage to the battery as "severe."

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NTSB Investigator Mike Bauer examines the inside of a Boeing 787 under investigation at Boston's Logan International Air. (Handout/ Reuters)

The battery fire is of particular interest because lithium batteries generally have not been used on large planes before the 787.

Sinnett says the nature of lithium ion batteries means no fire extinguisher system will stop them from burning once they start.

The NTSB said it took firefighters 40 minutes to put out Monday's fire.

There have been other incidents, as well.

Last month, a United Airlines 787 flying to Newark, N.J., from Houston was diverted to New Orleans because of an electrical problem with a power distribution panel.

United said last month it would delay the start of 787 flights from Houston to Lagos, Nigeria, because it wanted to "improve the reliability of the aircraft."

The Wall Street Journal, without naming its source, reported that United discovered wiring had been improperly installed in 787 electrical components associated with the same auxiliary power unit that started Monday's fire.

Boeing 'working closely' with NTSB

Last month, the U.S. Federal Aviation Administration ordered inspections of all 787s after fuel leaks on two aircraft.

It said the leaks were caused by incorrectly assembled couplings in fuel lines and that the leaks could result in a loss of power or engine fire.

In its release about the battery pack incident, Boeing said it was "working closely with the NTSB, our customer and other government agencies."

"Nothing that we’ve seen in this case indicates a relationship to any previous 787 power system events, which involved power panel faults elsewhere in the aft electrical equipment bay." Boeing said.

Even before Boeing's comments, its shares traded higher Wednesday, reversing a 4.6 per cent on Monday and Tuesday, which knocked $2.7 billion US off its market capitalization.

They closed up $2.63, or 3.55 per cent, at $76.76 on the New York Stock Exchange.

"A tough week for Boeing, for sure," Robert Kokonis, president of Toronto-based AirTrav Inc., told CBC News, "but we expect Boeing will solve all these problems."

Kokonis said such issues are common with the introduction of a new model and expected them to be forgotten within a matter of weeks.

Air Canada has 37 on order

He noted that no airline customer has cancelled an order.

"Although it’s hitting Boeing [stock] in the near term, we believe that they will rebound," Kokonis said.

"These things do take a while to work out, but I have no doubt whatsoever this is a safe airplane."

But he said Boeing has to get the fuel leak problem fixed soon, even if it isn’t a safety issue, if only for reasons of optics.

"It doesn’t sound good, especially when you’re about to embark on a 10- or 11-hour flight non-stop across the pole from Boston or Toronto."

The 787, which entered commercial service in November 2011, promises a smoother travel experience and is 20 per cent more fuel-efficient than older long-range models.

After years of delays, Boeing has now delivered 49 of the planes, with almost 800 more on order, including 37 for Air Canada that are expected to begin to be delivered next year.

Air Canada wouldn't say if the incidents have prompted the airline to have concerns about its order. 

"They are still looking into it now so it is really not possible to comment," Air Canada spokeswoman Isabelle Arthur wrote in an email.

So far, most analysts are sticking with the company, waiting to see the conclusion of the investigation into the battery fire.

Jason Gursky, analyst with Citi Investment Research, wrote "these incidents — while unfortunately clumped together — do not signal grave issues with the long-term prospects for this aircraft, in our view."

However, Carter Leake, an analyst at BB&T, was more concerned about the latest 787 issue, and recommended that investors hold off on buying the aircraft maker’s stock for now.

With files from The Canadian Press and The Associated Press