Rolls-Royce has finally given more information on how it aims to solve the problems with the Trent 1000 Package C engines that power some 787s, while recognizing the “unacceptable levels of disruption” its customers continue to face.

The UK aero-engine company said Wednesday it is accelerating the development of the permanent fix to the intermediate pressure compressor rotor issue on Package C engines, and that it has installed a revised compressor blade in an engine scheduled for testing in early June. “We aim to have first parts available for engine overhaul in late 2018, rather than 2019 as originally planned,” Rolls-Royce civil aerospace president Chris Cholerton said.

Rolls is also speeding the development of the new blade and a dedicated facility in Derby to build engines on which it will test it. Additionally, Rolls-Royce developed new on-wing inspection techniques to support airlines in meeting the requirements of the airworthiness directives “as quickly and efficiently as possible,” it said. 

The U.S. Federal Aviation Administration and the European Aviation Safety Agency in April issued airworthiness directives for Trent 1000-powered Boeing 787 operators mandating the completion of additional intermediate compressor inspections by June 9.

About 380 Trent 1000 Package C engines operate in service and needed inspections on their compressors. The majority passed inspection and therefore continue to fly, according to a Rolls-Royce spokesman who declined to enumerate “majority.” An executive close to the Trent 1000 Package C engines issue told AIN that 29 percent of the powerplants have failed the initial checks required by regulators and remain grounded. Some 80 percent of the engines have undergone checks by now, the executive said.

Cholerton admitted Rolls-Royce expects the number of aircraft affected “to rise in the short term, as the deadline for the completion of initial inspections approaches,” though it remains tight-lipped on the actual numbers. “We are not confirming number of aircraft grounded,” the spokesman said.

Operators have grounded some 30 to 35 Boeing 787s due to the engine problem and that number will likely rise to a peak of 50 because of a sudden rush of inspections for the June deadline.

“We fully recognize the unacceptable levels of disruption our customers are facing,” said Cholerton. “[We are] intensely focused on minimizing this and we have set our teams the challenge of doing everything we can to recover our customers’ operations as swiftly as possible.” Along with accelerating a permanent fix for the issue, he noted, the OEM has tripled maintenance capacity for affected engines in a matter of months and introduced a new inspection technique. Roll-Royce realigned resources and now has assigned 200 people to the program.