(Reuters) – Budget airline Norwegian Air Shuttle plans to take its second Boeing Dreamliner out of operation for precautionary checks after repeated hydraulic and electrical faults led to the grounding of its other one.

The carrier said on Wednesday the second Dreamliner had had fewer problems than the other plane and the move was more a precautionary measure. It expects the checks to take place once the grounded jet is back in service, probably late next week.

The move came as one of Boeing’s largest customers, which owns the two jets and rents them to Norwegian for a fee, threw its weight behind the airline in a row over 787 reliability.

“It’s got to improve: it can’t keep doing what it has been doing and it has been very frustrating,” Henri Courpron, chief executive of Los Angeles-based International Lease Finance Corp, told Reuters during an aviation event in Barcelona.

“Norwegian have launched their wide-body operation on the back of the 787 order and it is very difficult for an airline to start a new product in a new market if the airplane is not as reliable as you would like.”

The Dreamliner was supposed to be a game changer for the aviation industry as its light weight body and sophisticated engines cut fuel consumption by 20 percent.

But it has been beset by problems, including a battery fire that grounded the model for months this year and forced Boeing to come up with a new battery design.

Norwegian Air grounded one of its two Dreamliners on September 28, asking Boeing for repairs after repeated faults in its first month of operation left passengers stranded in cities around the world including Bangkok and New York.

“Boeing has gone through the plane completely and made all the necessary improvements,” spokeswoman Charlotte Holmbergh Jacobsson said of the grounded plane. “We aim to have it back in operation towards the end of next week.”

Contrary to previous plans to test the plane on shorter routes, Norwegian Air will put the repaired jet immediately into long-haul service, she said.

Boeing said it expected checks on the second plane would take several days.

The Dreamliners are central to Norwegian Air’s plans to ramp up its long haul operations to Asia and North America. It expects to have another six of the planes by 2015.

(Reporting by Joachim Dagenborg, Tim Hepher; Writing by Balazs Koranyi; Editing by Pravin Char and Mark Potter)