The European Union Aviation Safety Agency (EASA) has mandated an airworthiness directive (AD) for the Rolls-Royce Trent 1000 engine, integral to the operation of the Boeing 787 family. This directive comes after Rolls-Royce discovered a potential fault where the high-pressure compressor (HPC) mini-disc anti-rotation block might dislodge into critical components of the engine during flight.
This issue affects eight variants of the Trent 1000 engine, contingent upon whether they incorporate the Rolls-Royce service bulletins “SB 72-G319” or “SB 72-G893.” Engines already equipped with the Rolls-Royce “mod 72-AK645,” whether installed during initial production or subsequently during maintenance, are exempt from this directive.
In response to these findings, Rolls-Royce has issued a non-modification service bulletin (NMSB), “Trent 1000 72-AK540 Revision 2,” detailing inspection protocols. EASA, having finalized the AD on June 28, stipulates that the directive will take effect on July 12. It mandates that operators undertake repetitive borescope inspections of the HPC rear drum and inter-disk cavities, adhering to a schedule of every 800 engine flight cycles (EFC)—each cycle representing a takeoff and landing sequence.
Should these inspections reveal any anomalies, such as a misplaced or dislodged HPC mini-disc anti-rotation block or other foreign objects, the affected engine must be decommissioned immediately. For operators employing the Rolls-Royce Engine Health Monitoring (EHM) service, EASA has provided an alternative compliance method, potentially streamlining the inspection process.
The directive primarily impacts a small subset of Boeing 787-8 aircraft equipped with the pertinent Trent 1000 engine variants. According to data from ch-aviation, only 78 of these aircraft are in service, and it remains uncertain whether these have the “mod 72-AK645” modification. Notably, the last 787 equipped with one of the affected engine types was delivered to EL AL, registered as 4X-ERC, in February 2020.
Additionally, the list of aircraft potentially affected includes two ex-Norwegian Boeing 787s that were scrapped at Glasgow Prestwick Airport (PIK), marking them as the first such models to be decommissioned commercially. Another was dismantled at Roswell Air Center (ROW) in March, although it featured General Electric (GE) GEnx engines, thus not falling under this specific AD.
This directive underscores the ongoing challenges within the aviation industry to ensure the safety and reliability of its fleet, prompting continued scrutiny and preventive maintenance protocols.