By Lisa Barrington and Joanna Plucinska

(Reuters) -Cathay Pacific Airways said it would return all Airbus A350s to operation by Saturday following engine fuel lines repairs, while other airlines were waiting for guidance from manufacturer Rolls-Royce on whether they needed to inspect their engines.

Several Asian A350 operators have chosen to carry out their own precautionary inspections after Cathay Pacific found 15 planes that needed fuel line repairs following the in-flight failure of an engine part this week that forced its A350-1000 passenger plane to dump fuel and return to Hong Kong.

Other airlines have said they are closely monitoring the situation and are in touch with Rolls-Royce.

The inspections and repairs to Cathay’s fleet of 48 A350 widebody jets made the carrier cancel 45 round trips on mostly regional Asian routes this week, it said in its latest update.

Cathay Pacific said six A350s had been repaired and were cleared to operate. The remaining nine were expected to be fixed and returned to operation by Saturday.

“This was a significant situation for Cathay to manage as the engine component failure was the first of its type to occur on any A350 aircraft anywhere in the world,” Cathay’s Chief Operations and Service Delivery Officer Alex McGowan said.

The airline, which operates A350-900 and A350-1000 planes fitted with different Rolls-Royce engines, did not specify which models were being repaired.

A person familiar with the matter said a leak in a fuel system appeared to have caused a brief engine fire that was quickly extinguished by the crew of a Zurich-bound A350-1000 plane on Monday, which returned to Hong Kong just over an hour after take-off.

There were no immediate signs that the incident would trigger significant regulatory action involving the A350 fleet, the person added.

NO OFFICIAL MANDATE

Rolls-Royce, which makes the two types of engines for the A350-900 and the slightly longer A350-1000, has not issued an official mandate for fleet-wide inspections of either engine type and airlines are taking different approaches.

Still, a number of carriers have said they are either inspecting their fleet or are in touch with Rolls-Royce over the issue at Cathay.

Tokyo-based Japan Airlines (JAL), which has five new A350-1000s, said on Wednesday it was conducting its own engine inspections.

By Tuesday, three had been inspected and found to be safe, the carrier said, and the remaining two would be checked on Wednesday.

Qatar Airways, which operates the most A350-1000s, on Tuesday said the issue had no impact on its planes and it continued to monitor any developments.

British Airways and Virgin Atlantic, which operate A350-1000s, did not respond to a Reuters request for comment.

Taiwan’s Starlux, which has six A350-900s said: “Out of caution, we have contacted Rolls-Royce, the engine manufacturer, and are awaiting an official reply.”

Singapore Airlines is inspecting its A350-900 engines as a precaution, but said flights were not impacted.

Air China, a major A350-900 operator, will perform general engine checks, reported Caixin, a Chinese business and economics publication, on Tuesday. Air China did not respond to a request for comment.

Air France and Lufthansa, which also have A350-900s, also told Reuters they are in touch with Rolls-Royce and Airbus and are monitoring the situation closely.

The incident caused a sharp drop in the shares of British engine maker Rolls-Royce on Monday, but they bounced back on Tuesday as concerns over implications for the global fleet eased and some analysts called the sell-off overdone.

Rolls Royce shares were down 0.1% at 0824 GMT on Wednesday.

(Reporting by Rishav Chatterjee in Bengaluru, Joanna Plucinska in London and Lisa Barrington in Seoul; Editing by Rashmi Aich, Jamie Freed, Tomasz Janowski and Miral Fahmy)

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