Le 18 juin, l'EASA (Agence européenne pour la sécurité aérienne) a émis un consigne de navigabilité sur certains moteurs Rolls-Royce Trent 1000 et Trent 7000 dont les disques de la turbine haute pression requièrent un suivi attentif.
AD No.: 2021-0146 Issued: 18 June 2021
Design Approval Holder’s Name:
ROLLS-ROYCE DEUTSCHLAND Ltd & Co KG
Trent 1000 and Trent 7000 engines
Effective Date: TCDS Number(s): Foreign AD: Supersedure:
25 June 2021 EASA.E.036 Not applicable None
ATA 05 – Time Limits / Maintenance Checks – High Pressure Turbine Disc – Inspection
Trent 1000 ‘Pack B’ engines, models Trent 1000-A, Trent 1000-AE, Trent 1000-C, Trent 1000-CE, Trent 1000-D, Trent 1000-E, Trent 1000-G and Trent 1000-H, all engine serial numbers (ESN);
Trent 1000 ‘Pack C’ engines, models Trent 1000-A2, Trent 1000-AE2, Trent 1000-C2,
Trent 1000-CE2, Trent 1000-D2, Trent 1000-E2, Trent 1000-G2, Trent 1000-H2, Trent 1000-J2, Trent 1000-K2 and Trent 1000-L2, all ESN;
Trent 1000 ‘TEN’ engines, models Trent 1000-AE3, Trent 1000-CE3, Trent 1000-D3, Trent 1000-G3, Trent 1000-H3, Trent 1000-J3, Trent 1000-K3, Trent 1000-L3, Trent 1000-M3, Trent 1000-N3, Trent 1000-P3, Trent 1000-Q3 and Trent 1000-R3, all ESN; and
Trent 7000-72 and Trent 7000-72C engines, all ESN.
These engines are known to be installed on, but not limited to, Boeing 787 and Airbus A330 (NEO) aeroplanes.
For the purpose of this AD, the following definitions apply:
The applicable TLM task: Rolls-Royce Trent 1000 Time Limits Manual (TLM) T-Trent-10RRB Revision 23, or TLM T-Trent-10RRC Revision 20, sub-task 05-20-01-890-012; Trent 1000 TLM T-Trent-10RRT Revision 16, sub-task 05-20-01-890-010; or Trent 7000 TLM T-T7000-1RR Revision 7, sub-task 05-20-01-890-002; as applicable.
Affected part: High-pressure turbine (HPT) discs, having a Part Number (P/N) and serial number (s/n) as listed in Appendix 1 of this AD.
Qualified shop visit: Any engine shop visit where the 04 (HPT module) to 05 (Intermediate Pressure Turbine module) flange is separated.
Groups: Group 1 engines are those that have an affected part installed. Group 2 engines are those that do not have an affected part installed.
Occurrences have been reported where, during an engine shop visit, in the context of which it is expected that the HPT disc is disassembled to a ‘piece-part’ condition, HPT maintenance tasks were accomplished in such a way that the HPT disc was never fully isolated in a ‘piece-part’ level condition at any moment during this shop visit. The applicable Rolls-Royce engine maintenance manual (EMM) contains instructions to accomplish focused inspections of the HPT disc when it is at ‘piece-part’ level, but the specific provisions to establish whether this part should be at ‘piece-part’ level in certain circumstances may be considered ambiguous. As there was no formal unambiguous ‘piece-part level’ condition of the affected part at any time during the shop visit, the engine was released to service, without inspecting the affected part as intended by the applicable EMM.
Whereas the maintenance activities as described above may not have been in direct violation of the instructions published in the applicable Rolls-Royce EMM, they did conflict with the intent of accomplishing focused inspections of critical parts when those parts are in such a condition that these inspections can be done without further substantial disassembly. Such opportunity-driven inspections are part of the service management plan for engine critical parts, which defines in- service processes for maintenance and repair, necessary to maintain the critical part lives established during engine certification.
This condition, if not corrected, could lead to HPT disc failure, possibly resulting in high-energy debris release, with consequent damage to, and reduced control of, the aeroplane.
To address this potential unsafe condition, Rolls-Royce plans to publish appropriate documentation to ensure that the determination of when to accomplish any focused critical parts inspection is unambiguous and adequate to meet the intent of opportunity-driven inspections as relied upon in the service management plan for engine critical parts.
The engines on which this inspection was not accomplished have been identified. Pending the publication of appropriate documentation, it has been determined that the affected engines must be inspected to ensure an acceptable level of safety for continued operation.
For the reasons described above, this AD requires a one-time inspection of the affected part and, depending on findings, replacement.
This AD is considered an interim action and further AD action may follow.
Required Action(s) and Compliance Time(s):
Required as indicated, unless accomplished previously:
(1) For Group 1 engines: During the next qualified shop visit (as defined in this AD) after the
effective date of this AD, disassemble the affected part to ‘piece-part’ level condition and, before reassembly, inspect the affected part in accordance with the instructions of the applicable TLM task.
(2) If, during the inspection as required by paragraph (1) of this AD, any discrepancy is detected
that exceeds the ‘accept’ criteria as specified in the applicable TLM task, before release to service of the engine, replace the affected part with a serviceable part. This can be accomplished in accordance with the applicable Rolls-Royce maintenance instructions.
(3) For Group 1 and Group 2 engines: From the effective date of this AD, it is allowed to install on
any engine an affected part, provided that, before installation, the part has passed (no defects found) the inspection as required by paragraph (1) of this AD.
(4) Compliance with this AD does not change, or affect in any other way, compliance of an engine