Boeing Co. told airlines that some Dreamliners with General Electric Co. engines must bypass thunderstorms as a precautionary measure, the latest advisory on the 787 that was grounded globally earlier this year.

Dreamliners, powered by the GEnx engines, must avoid flying within 50 nautical miles (93 km) of thunderstorms to reduce chances of ice crystals forming and reducing the engine’s thrust, the plane-maker said in an emailed statement on Saturday. Boeing has also alerted operators of 747-8s with GE engines, spokeswoman Yvonne Leach said.

The advisory prompted Japan Airlines Co., the world’s second-largest Dreamliner operator, to switch to other aircraft on routes linking Delhi and Singapore with its Tokyo base. Boeing had trouble on the plane this year as melting of lithium-ion batteries in January grounded the global fleet of 787s, the longest grounding of a commercial aircraft by U.S. and Japanese regulators since jets were introduced in the 1950s.

“This looks a lot like a classic teething issue,” Richard Aboulafia, a vice president of Teal Group, said by email. “It’s probably isolated to just the engine, and even then just one of the two engines available as options. It’s also probably easily fixed with a software tweak, rather than any kind of hardware modification.”

The carbon-fiber jet entered service with All Nippon Airways in October 2011 after 3½ years of delays. ANA, the world’s largest operator of the Dreamliner, uses Rolls-Royce PLC’s engines on its planes.

There have been six cases since April of planes with GEnx engines temporarily losing thrust in high-altitude icing conditions, GE said Saturday. Five were with 747-8s and one was with a 787, according to the emailed statement.

GE is working on software modifications to eliminate the problem and expects them to be available in the first quarter of next year, it said.

Boeing said it will “work closely” with GE to address the issue. ANA hasn’t received any notification to avoid certain weather conditions, Maho Ito, a spokeswoman for the carrier, said Saturday.

Calls to United Continental Holdings Inc., the only U.S. Dreamliner operator, weren’t returned Sunday. Air India has obtained a “procedural advisory” from Boeing on this issue, spokesman G. Prasada Rao said Monday.

Earlier this month, Boeing surpassed 1,000 orders for the 787 Dreamliner at the Dubai Air Show.

JAL will replace 787 Dreamliners on flights between Tokyo and Delhi with 777s starting Monday until Saturday, and will also switch to 767s on its Tokyo-Singapore route, it said in a statement Saturday. The Tokyo-based carrier will make a decision on the flight schedule from Dec. 1 this week, Jian Yang, a spokesman at Japan’s second-largest carrier, said Monday.

JAL will put the 787s on Tokyo-Beijing flights, whose routes are less likely to encounter thunderstorms, said Yuichi Kitada, a general manager in JAL’s engineering department.

“There may be cases where we wouldn’t be able to go all the way round the cloud formation and we’d have to turn back,” he said Saturday. “We’re at the first step of discussing a solution to this problem with Boeing and GE.”

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