Rolls-Royce engine corrosion spurs ANA to check Dreamliners

Bloomberg

ANA Holdings Inc. is canceling flights as the world’s biggest operator of Boeing Co.’s 787 Dreamliner checks for corrosion in the jet’s Rolls-Royce Holdings Plc engines.
The Japanese airline canceled nine flights scheduled for its 50-jet Dreamliner fleet for Friday and may scrub more than 300 trips through the end of September as it deals with cracking in the medium-pressure turbines of the Trent 1000 engines, Takeo Kikuchi, a deputy senior vice president of engineering and maintenance, told reporters on Thursday in Tokyo.
The disruption is the largest 787-related miscue for ANA since 2013, when Boeing and regulators grounded the global Dreamliner fleet after lithium-ion batteries caught fire on two jets. About 38 percent of the 787s in service are powered by the Trent 1000, while the rest are outfitted with General Electric Co. engines.
The latest problem came to the fore as ANA investigated why a 787 engine overheated during a February flight. That jet returned to Kuala Lumpur airport after receiving a warning that the temperature of the exhaust gas from its right engine had spiked. ANA has encountered corrosion in turbines since then, most recently on
August 20.

ANA-Specific
The difficulty appeared to be specific to ANA, which frequently uses the wide-body, carbon-composite aircraft for short flights. Rolls-Royce and Boeing said they were working with the Japanese carrier to lessen the impact.
“This issue is limited to a small proportion of the ANA fleet,” a spokesman for London-based Rolls-Royce said, adding that no other airlines were affected.
The European Aviation Safety Agency is considering releasing a service bulletin recommending action from the continent’s carriers, a spokeswoman said by e-mail. There are no US-registered Boeing 787 aircraft with Rolls-Royce engines.
The issue stems from sulfidation-corrosion cracking and is “not a fan blade problem,” the Federal Aviation Administration said in a statement by e-mail. The U.S. regulator “has reviewed the problem and determined it is not a safety concern.”
Wear and Tear
Flying shorter flights would produce more wear and tear on an engine designed to spend 10 or more hours cruising between continents, said Robert Mann, an aviation consultant. Corrosion caused by sulfides could be caused by the “combination of higher temperature stresses in the climb portion” of flight, followed by shorter than typical periods at cruising altitude, he said. Mann likened the situation to the pressure on the exhaust system of a car driven only short distances.
“The engine never heats up fully to drive the moisture out the exhaust system. Then it shuts down and condensation causes the rust to gather,” he said.
ANA has been in talks with Rolls-Royce over the engines since March, said Kikuchi, the airline’s engineering executive. The carrier, which was the initial customer for the 787, in 2011, operates almost a third of the global Dreamliners with Trent 1000 engines, according to a Morgan Stanley research report.
This wasn’t the first time corrosion has been found in the Rolls-Royce power plants. The problem cropped up in Trent 1000 gearboxes in 2012 and was quickly resolved, Jaime Rowbotham, an analyst at Morgan Stanley, said in a note to clients.
New Model
Rolls-Royce announced at the Farnborough Air Show last month that European safety regulators had certified an upgraded version of the Trent 1000 that borrows technology developed for a newer engine powering Airbus Group SE’s A350 jetliners.
“We expect the new derivative will have been designed to avoid the issues ofits predecessor,” Rowbotham wrote.
Rolls-Royce fell 1.8 percent to 774 pence at the close in London. ANA gained 1.6 percent to close at 279.5 yen in Tokyo. Boeing was little changed at $132.89 at 3:57 p.m. in New York.
Financial Impact
Engine problems have affected flights three times, Kikuchi said. ANA expects to lose 55 million yen ($548,000) from Friday’s cancellations and doesn’t yet know the total financial impact, he said.
Since Rolls gets most of its profit from hourly maintenance contracts that charge airlines for the time an engine spends in the sky, the company’s revenue could fall if ANA cancels hundreds of flights.
Rolls maintains “a conservative provisioning policy” and “will update the market if we believe any further action is required,” the spokesman said.