The European Aviation Safety Agency (EASA) has mandated Rolls-Royce-recommended interval reductions on Trent 700 low-pressure (LP) compressor blade inspections based on "further analysis" by the OEM that necessitates the change.
The new inspection interval is 1,200 cycles, half of what was mandated in a 2016 airworthiness directive (AD).
"Since that AD was issued, the results of further analysis determined that the inspection threshold must be further reduced," EASA notes in an AD effective Dec. 20.
The AD, which affects all Trent 700s—one of two engine choices on the current-generation Airbus A330—the latest step to reduce risk of LP compressor blade "release events" that have occurred in the fleet. Rolls-Royce pulled some blades out of service, but "causal factors still exist that are not fully understood," EASA noted in a 2013 AD that set the inspection threshold at 3,000 cycles. The interval was reduced again in 2014 and 2016.
The reduction to 1,200 cycles was recommended in an October 2017 service bulletin.
Fiji Airways told EASA that reducing the interval from 2,400 to 1,200 cycles takes the task out of its scheduled A330 C-check package, which will burden the operator. "C check is the best instance for [Fiji] to carry out the inspection of the LPC blades in an MRO facility where the technicians with the specified skill set and training are available," the airline said. Fiji requested a 1,500-cycle interval to align with its C-check schedule.
EASA noted that the new, 1,200-cycle interval "coincides with the scheduled fan blade root relube recommendations as published by" Rolls-Royce, "when operators will already be removing the subject fan blades from the fan disc in order to perform other maintenance."
EASA also clarified that spare blades that had accumulated 1,200 cycles since their last inspection must be re-inspected even if they were cleared under the previous AD's 2,400-cycle interval.
While the EASA AD only applies to European-registered aircraft, the directive is expected to be adopted globally. Aviation Week's Commercial Fleet & MRO database shows about 1,500 Trent 700s in service around the world.