EASA plans to mandate inspections of certain Rolls-Royce Trent 1000 low-pressure turbine (LPT) discs following word from the manufacturer that contact between the parts and nearby seals can lead to cracks.

EASA’s proposed airworthiness directive (AD), issued July 6, calls for operators of Boeing 787s with Trent 1000 “Package C” variants to inspect LPT stage 3 and 4 disc seal fins for cracks.

“Analysis of certain [LPT] discs in service has determined that, due to rubbing contact with interstage static seals, cracks may initiate in the front seal fins which could lead to cracks in the disc of the affected parts,” EASA explained. 

Rolls-Royce issued a service bulletin on June 29 recommending fluorescent penetrant inspections of the fins during the next engine refurbishment shop visit. Discs with cracked fins must be replaced.

The directive does not say whether the issue has been linked to any in-service incidents.

The issue is not related to Rolls’ ongoing program to address high-pressure turbine blade durability issues that have plagued much of the Trent 1000-powered 787 fleet for several years.