By Lisa Barrington and Tim Hepher
(Reuters) -Hong Kong's Cathay Pacific Airways (OTC:CPCAY) said on Tuesday it had inspected its entire Airbus A350 fleet after the in-flight failure of an engine part and found 15 aircraft with components that needed replacement.
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 the Zurich-bound A350. There were no immediate signs that Monday's incident would trigger significant regulatory action involving the A350 fleet, the person added.
The A350-1000 returned to Hong Kong just over an hour after take-off.
Aviation Herald, an air safety publication, reported the jet had turned back after a cockpit alert warning of a fire in one of its two Rolls-Royce (OTC:RYCEY) XWB-97 engines.
After carrying out routine checks and discharging a fire bottle, the crew dumped fuel and returned to base, it said.
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 shares rose 2.4% and were among the top gainers on London's blue-chip FTSE 100 index.
Cathay Pacific said three of the 48 Rolls-Royce-powered planes it had inspected had gone through successful repairs and all were expected to resume operation by Saturday.
It cancelled at least 34 round-trip flights due to the disruption to its fleet.
Data from flight tracking service FlightRadar24 showed other major operators of the A350-1000 and the smaller, more popular A350-900, still flying their aircraft on Tuesday.
Rolls-Royce has not yet issued a directive to airlines regarding possible inspections, according to an industry source who was not authorised to speak publicly about the matter.
Such a step is typically the first sign of an official instruction from regulators, though they can act independently.
Japan Airlines (JAL), which has five A350-1000s, said it had asked Rolls-Royce for more information and had not stopped A350 flights in the meantime.
"If the engine manufacturer takes any further action, we will respond accordingly," a JAL spokesperson said.
Cathay Pacific said it had secured spare parts for the components that needed to be replaced. Rolls-Royce said the replacement could take place while the engine remained on-wing.
The engine manufacturer said it was committed to working closely with Cathay Pacific, Airbus and investigators in Hong Kong, whose safety agency confirmed it had launched a probe.
Cathay Pacific has not specified which engine component failed, but the carrier said it was the "first of its type to suffer such failure on any A350 aircraft worldwide".
A person familiar with the matter said the incident involved a leak in a system designed to inject fuel to the engine.
The system comprises a pipe that feeds fuel from an entry point or manifold to a nozzle that sprays fuel into the combustion chamber, the hot inner core of the engine.
Sources said partially scorched parts were being analysed at Rolls-Royce facilities on behalf of Hong Kong investigators, but that no leaks had been found so far in other engines.
Experts say such problems are rare but, barring a deeper flaw, generally raise fewer alarms than the failure of one of the major rotating parts such as a turbine blade.
However, any widespread further inspections could be disruptive to airlines at a time when engine repair shops are already congested following increased wear on modern engines, especially those of Pratt & Whitney on smaller Airbus jets.
Airbus said it was offering "full technical support".
'PRECAUTIONARY MEASURE'
There are 86 A350-1000s in operation worldwide, compared with 526 A350-900s, according to Airbus data. Together, they compete with the Boeing (NYSE:BA) 787 and 777 on long routes. Cathay operates a mixed Airbus and Boeing fleet.
Top A350-1000 operators include Qatar Airways with 24, British Airways which is owned by the International Airlines Group (LON:ICAG) with 18, Cathay Pacific also with 18, Virgin Atlantic with 12 and Etihad Airways and JAL with five each.
Qatar Airways said its fleet of 24 A350-1000s was not affected and it continued to monitor developments.
Although the part failure occurred on one of its 18 A350-1000 jets, Cathay Pacific said it was also inspecting its 30 smaller A350-900s as a "precautionary measure".
It said it had "identified a number of the same engine components that need to be replaced".
Malaysia's national carrier, which also has A350-900s in its fleet, has consulted Airbus and is operating as normal, the country's Transport Minister Anthony Loke Siew Fook said.
Singapore Airlines (OTC:SINGY) said it was reviewing the engines on A350-900s but there was no impact on flights. It does not have any A350-1000s.
Cathay Pacific shares ended the day down 0.6%.