All potentially faulty gearbox components on Rolls-Royce Trent 1000s have been isolated, enabling regulators to lift a safety notice imposed on Trent-powered Boeing 787s last year.
The notice, issued in July 2012, followed the discovery of a corrosion problem on crown wheel gears in the transfer gearbox, traced to a change in the manufacturing process.
European Aviation Safety Agency directives required that the affected gearbox assemblies be replaced.
All affected crown wheel gears manufactured using the suspect process have since been "retrieved, quarantined and subsequently scrapped", says EASA, while the manufacturing process has been revised to prevent recurrence.
"Based on this information EASA [has] determined that the unsafe conditionno longer exists and cannot develop on any engine," it adds in a document formally lifting the safety notice.