AD 2017-08-10 Airworthiness Directives; Rolls-Royce plc Turbofan Engines

This AD applies to all Rolls-Royce plc (RR) RB211-Trent 970-84, RB211-Trent 970B-84, RB211-Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84, and RB211-Trent 980-84 turbofan engines.

Comply with this AD within the compliance times specified, unless already done. (1) Within the compliance times and using the service information specified in Table 1 to paragraph (f) of this AD, accomplish on-wing inspections of the TBH features using the following instructions, as applicable. (i) If during any on-wing inspection of the TBH mount lug run-outs done using the Accomplishment Instructions, paragraph 3.A.(1), of RR Alert Non-Modification Service Bulletin (NMSB) RB.211-72-AG971, Revision 2, dated May 5, 2016, any cracks less than or equal to 2 mm in length are found, remove the engine from service within 10 flight cycles (FCs). If any cracks greater than 2 mm are found, remove the engine from service before further flight. (ii) If during any on-wing inspection of the TBH mount lug run-outs done using the Accomplishment Instructions, paragraph 3.A.(2), of RR Alert NMSB RB.211-72-AG971, Revision 2, dated May 5, 2016, any crack indications resulting in an inspection signal with an amplitude of 50% full screen height or more are found, remove the engine from service before further flight. (iii) If during any on-wing inspection of a pre-mod 72-J024 TBH, any crack or damage is found on the TBH mount lug forging leading edge (LE) areas, re-inspect the engine or remove the engine from service in accordance with the Accomplishment Instructions, paragraph 3.A.(3)(t), of RR Alert NMSB RB.211-72-AH154, Revision 5, dated May 5, 2016. (iv) If during any on-wing inspection of a post-mod 72-J024 TBH, any crack is found on the TBH mount lug forging LE or cutback areas, re-inspect the engine or remove the engine from service in accordance with the Accomplishment Instructions, paragraph 3.A.(3)(t), of RR Alert NMSB RB.211-72-AJ101, dated May 5, 2016. (2) Within the compliance times and using the service information specified in Table 2 to paragraph (f) of this AD, perform in-shop inspections of the TBH features using the following instructions, as applicable. (i) If during any in-shop inspection of the TBH, any crack is found on the TBH mount lug or central male catcher run-outs, replace the TBH with a TBH eligible for installation before the engine is returned to service. (ii) If during any in-shop inspection of the TBH, any crack is found on the top core vanes, reject as unserviceable or repair the TBH in accordance with the Accomplishment Instructions, paragraph 3.C.(1)(f), of RR Alert NMSB RB.211-72-AG971 Revision 2, dated May 5, 2016, before the engine is returned to service. (iii) If during any in-shop inspection of a pre-mod 72-J024 TBH, any crack or damage is found on the TBH mount lug forging LE areas, reject as unserviceable or repair the TBH in accordance with the Accomplishment Instructions, paragraph 3.B.(2)(u)(ii), of RR Alert NMSB RB.211-72-AH154, Revision 5, dated May 5, 2016, or the Accomplishment Instructions, paragraph 3.C.(1)(f), of RR Alert NMSB RB.211-72-AG971, Revision 2, dated May 5, 2016, before the engine is returned to service. (iv) If during any in-shop inspection of a post-mod 72-J024 TBH, any crack is found on the TBH mount lug forging LE or cutback areas, repair the TBH in accordance with the Accomplishment Instructions, paragraph 3.B.(2)(u)(ii), of RR Alert NMSB RB.211-72-AJ101, dated May 5, 2016, or the Accomplishment Instructions, paragraph 3.C.(1)(f), of Alert NMSB RB.211-72-AG971, Revision 2, dated May 5, 2016, before the engine is returned to service. Table 1 to Paragraph ( f )—TBH On-Wing Inspections Affected TBH P/N and feature Applicable NMSB and paragragph Alternate NMSB instructions acceptable for prior compliance Initial inspection Repeat inspection interval (not to exceed) All—Mount Lug Run-outs RB.211-72-AG971, Revision 2, Paragraph 3.A In-shop: RB.211-72-AG971, Revision 2, Paragraph 3.B or 3.C Before exceeding 2,200 FCs since new 2,200 FCs. Pre-mod 72-J024 TBH—Mount Lug Forging LE Areas—for a TBH that has not exceeded 900 FCs since new on April 7, 2014 RB.211-72-AH154, Revision 5, Paragraph 3.A In-shop: RB.211-72-AH154, Revision 5, Paragraph 3.B., or RB.211-72-AG971, Revision 2, Paragraph 3.C Before exceeding 1,000 FCs since new 1,000 FCs. Pre-mod 72-J024 TBH—Mount Lug Forging LE Areas—for a TBH that has exceeded 900 FCs since new on April 7, 2014 RB.211-72-AH154, Revision 5, Paragraph 3.A In-shop: RB.211-72-AH154, Revision 5, Paragraph 3.B., or RB.211-72-AG971, Revision 2, Paragraph 3.C Within 100 FCs after April 7, 2014 1,000 FCs. Post-mod 72-J024 TBH—Mount Lug Forging LE and Cutback Areas RB.211-72-AJ101, Paragraph 3.A In-shop: RB.211-72-AG971, Revison 2, Paragraph 3.C, or RB.211-72-AJ101, Paragraph 3.B Before exceeding 1,000 FCs since SB RB.211-72-J024 embodiment 1,000 FCs. Table 2 to Paragraph ( f )—TBH In-Shop Inspections Affected TBH P/N and feature Applicable NMSB and paragraph Alternate NMSB instructions acceptable for prior compliance Initial inspection Repeat inspection interval (not to exceed) All—Mount Lug Run-outs RB.211-72-AG971, Revision 2, Paragraph 3 On-wing: RB.211-72-AG971, Revision 2, Paragraph 3.A., or In-shop: RB.211-72-AG971, Revision 2, Paragraph 3.C Before exceeding 2,200 flight FCs since new 2,200 FCs. All—Top Core Vanes and Central Male Catcher Run-outs RB.211-72-AG971, Revision 2, Paragraph 3.C None Before exceeding 3,800 FCs since new 3,800 FCs. Pre-mod 72-J024 TBH—Mount Lug Forging LE Areas—for a TBH that has not exceeded 900 FCs since new on April 7, 2014 RB.211-72-AH154, Revision 5, Paragraph 3.B On-wing: RB.211-72-AH154, Revision 5, Section 3.A, or In-shop: RB.211-72-AG971, Revision 2, Paragraph 3.C Before exceeding 1,000 FCs since new 1,000 FCs. Pre-mod 72-J024 TBH—Mount Lug Forging LE Areas—for a TBH that has exceeded 900 FCs since new on April 7, 2014 RB.211-72-AH154, Revision 5, Paragraph 3.B On-wing: RB.211-72-AH154, Revision 5, Section 3.A, or In-shop: RB.211-72-AG971, Revision 2, Paragraph 3.C Within 100 FCs after the effective date of this AD 1,000 FCs. Post-mod 72-J024 TBH—Mount Lug Forging LE and Cutback Areas RB.211-72-AJ101, Paragraph 3.B On-wing: RB.211-72-AJ101, Section 3.A, or In-shop: RB.211-72-AG971, Revision 2, Paragraph 3.C Before exceeding 1,000 FCs since SB RB.211-72-J024 embodiment 1,000 FCs.

(1) If you performed inspections and corrective actions on an engine before the effective date of this AD, in accordance with earlier versions of RR Alert NMSB RB.211-72-AG971, Revision 2, dated May 5, 2016, or RR Alert NMSB RB.211-72-AH154, Revision 5, dated May 5, 2016, you met the requirements of paragraph (f)(1) or (2) of this AD, as applicable. (2) If, on or before April 7, 2014, you performed the inspections and corrective actions required by paragraphs (f)(1) and (2) of this AD using RR Technical Variance (TV) No. 124801, Issue 2, dated July 4, 2012 or earlier versions; or RR TV No. 124851, Issue 2, dated July 4, 2012 or earlier versions; you met the requirements for a mount lug run-out inspection. (3) If, on or before April 7, 2014, you performed the inspections and corrective actions required by paragraphs (f)(1) and (2) of this AD using RR Repeater TV No. 132043, Issue 1, dated March 25, 2013 or earlier versions; or using RR Repeater TV No. 132217, Issue 5, dated May 23, 2013 or earlier versions; you met the requirements for the mount lug forging LE inspections of this AD.

This AD was prompted by reports that references to certain service bulletins are incorrect. We are issuing this AD to prevent failure of the tail bearing housing (TBH), resulting in damage to the engine and to the airplane.

This AD replaces AD 2017-01-01, Amendment 39-18768 (82 FR 3146, January 11, 2017).