Rolls-Royce has been keen to find a permanent fix to problems which have beset the Trent 1000 engine and which, according to half-year results issued on August 2, have cost the company US$728 million, contributing to an overall pretax loss of US$1.7 billion.
The Trent 1000 engine has been the engine of choice of the Boeing 787 and a large portion of the engines have been affected. Rolls-Royce has now finished a raft of improvements which the company believes will be cleared for introduction within a few months. It is anticipated these improvements will allow earlier-standard Package B and C engine operators to resume long-range flights with no limits, while also relieving them of inspection burdens imposed earlier this year by regulators after the discovery of fatigue cracks. These improvements have focused on the three-shaft engine’s intermediate pressure (IP) spool.
According to Rolls-Royce’s large engines chief engineer Frank Haselbach: “We have to prove the newer system works, and laboratory testing showed us it is going well,” adding: “We have rolled 62%-plus of the fleet with the new blading and are sampling the first engines now. We will also pull engines off to prove the turbine system will have the lifetime we predict for it and, so far, we have not had any issues with the new blades. Some are already in the territory of 1,000-1,500 cycles.”
It was discovered that the principal problem was caused by “hot corrosion,” where thermal barrier coating on the IP turbine blades was stripped away prematurely, exposing the underlying material to low-cycle fatigue. Analysis of the phenomena showed this was tied primarily to operations in and around airports in the Asia-Pacific region where there are high concentrations of atmospheric sulfur. “It’s fundamentally pollution around big cities that have ‘dirty’ industries,” Haselbach further explained.
