The launch customer for the world's first passenger jet built mainly from lightweight carbon fiber said the move stemmed from a flawed process that could leave part of its UK-manufactured engines vulnerable to early corrosion.

The airline grounded five of its 11 Dreamliners but three of the twinjet airplanes have been fixed and are flying again.

The other two are waiting for parts from Rolls-Royce and could be out of action for a few weeks, an ANA spokesman said.

"The extent of the issue with ANA appears relatively minor at this stage, given that (three) of the aircraft have already returned to service," said RBC Capital Markets analyst Rob Stallard in a note on the incident.

"However, investors remained focused on all things 787, and we could see the reverberation of this problem in the stock prices of Rolls-Royce, Boeing and to a lesser extent United Technologies which has a much broader business base."

Shares in Boeing (BA.N), which invested heavily in the revolutionary jet, fell 3 percent in early trading, underperforming global shares sent lower by Europe's debt crisis. Rolls-Royce shares were also down 3 percent.

The glitch is the latest disruption to Boeing's flagship jet as the Chicago-based company recovers from a series of production delays that have come to typify the latest models being produced by Boeing and its European rival Airbus (EAD.PA).

In November, ANA reported a landing gear problem weeks after taking delivery of the first $194 million jet.

The latest problem involves a gearbox supplied by Hamilton Sundstrand, part of U.S. conglomerate United Technologies (UTX.N), but for now is contained to one fairly small batch.

Two people familiar with the matter said concerns over corrosion came to light during endurance testing in the UK on one of the Trent 1000 engines designed by Rolls-Royce, which competes with General Electric to power the Dreamliner.

During the ground test, corrosion was discovered on part of the gearbox used to drive ancilliary systems. Investigators traced this to a new manufacturing process that was immediately reversed, the people said, asking not to be named.

SUSPECT BATCH

"We have seen no such problems with our 787s. But we have found out that out of the 11 787s we own, five of them are carrying those parts. For those five aircraft, we have switched them with other aircraft and are continuing to operate the flights," ANA said in a statement.

A total of 17 engines contain gearboxes from the same suspect batch as the one used in the endurance test, eight of which have been delivered to ANA, industry sources said.

A further nine have been delivered to Boeing, raising the prospect that they may have to be repaired before they are delivered to their final airline customers.

Boeing was not immediately available to comment.

Airlines that selected Rolls-Royce as engine supplier for their 787s, and whose aircraft are believed to be coming up for delivery, include Poland's LOT and LAN Airlines of Chile.

"We have identified that a component on Trent 1000 engines fitted to Boeing 787 Dreamliners has a reduced service life. As a proactive measure, this component is being replaced in a number of engines," a Rolls-Royce (RR.L) spokesman said.

United Tech's Hamilton Sundstrand arm said it was working with the other aerospace suppliers to solve the problem.

As of end-June, only Japanese carriers were operating the 787 Dreamliner, which entered service with ANA in October.

Japan Airlines, which has four Boeing 787s in its fleet, uses alternative engines built by General Electric (GE.N) and therefore does not face problems similar to those affecting ANA, Seiji Takaramoto, a Japan Airlines spokesman, said.

A blowout on a different type of Rolls-Royce engine on the Airbus (EAD.PA) A380 in November 2010 led to delivery bottlenecks for the world's largest passenger plane as engineers swapped dozens of engines on the production line.

Rolls competes with GE to power both the A380 and the 787 Dreamliner. Shares in GE outperformed a weaker market on Monday. (Additional reporting by Tim Kelly, Scott Malone, Writing by Sarah Young, Tim Hepher, Editing by James Regan and David Cowell)

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