This document transmits Revision 9 to Service Bulletin RB211-72-AB482 Document History Service Bulletin Revision Status Supplement Revision Status Initial Issue Jul.21/95 Revision 1 Sep.29/95 Revision 2 Mar.11/96 Revision 3 Sep.27/96 Revision 4 Apr.18/97 Revision 5 May 23/97 Revision 6 May 24/97 Revision 7 Sep.7/99 Revision 8 Nov.15/01

Bulletin Revision 9 Remove Incorporate Reason for change All pages of the Service Bulletin Pages 1 to 12 of the Service Bulletin To reduce inspection intervals of RB211-524B-02, 524B2, 524B3 and 524B4 engines that have not been repaired to FRS5367/B.Printed in Great Britain Jul.28/03

RB211-524 SERIES PROPULSION SYSTEMS ALERT NON-MODIFICATION SERVICE BULLETIN



# RB.211−72−AB482 Transmittal - Page 1 of 2 Signed Date



# ALERT

ALERTLIST OF EFFECTIVE PAGES The effective pages to this Service Bulletin following incorporation of Revision 9 are as follows: Page Revision Number Revision Date

Bulletin R 1 9 Jul.28/03 R 2 9 Jul.28/03 R 3 9 Jul.28/03 R 4 9 Jul.28/03 R 5 9 Jul.28/03 R 6 9 Jul.28/03 R 7 9 Jul.28/03 R 8 9 Jul.28/03 R 9 9 Jul.28/03 R 10 9 Jul.28/03 R 11 9 Jul.28/03 R 12 9 Jul.28/03Printed in Great Britain



# RB.211−72−AB482 Transmittal - Page 21. Planning Information A. Effectivity (1) Boeing 747-400 Aircraft All RB211-524G and 524H engines not incorporating SB RB211-72-9764 (2) Boeing 747 Aircraft All RB211-524B2, 524C2 and 524D4 engines incorporating SB RB211-72-7221 or SB RB211-72-7998 but not incorporating SB RB211-72-9670 or SB RB211-72-9764 combustion liners

(3) Lockheed L-1011 Aircraft All RB211-524B-02, 524B3 and 524B4 engines incorporating SB RB211-72-7221 or SB RB211-72-7998 but not incorporating SB RB211-72-9670 or SB RB211-72-9764 combustion liners

B. Reason With the introduction of combustion liners featuring hairpin head location in RB211-524 engines, there has been a significant reduction in combustion liner related engine removals. However, in higher rated 524G/H engine marks, head section break-up has been apparent at lives in excess of 2000 cycles since new or 1000 cycles since repair. Whilst the majority of these events have been identified through routine condition monitoring, in line with the airline scheduled maintenance programme, a small number have resulted in secondary effects leading to combustion breakout and firewarning.

Non-Modification Service Bulletin 72-9768 (see 1.F. References) was issued in August 1993 recommending a periodic inspection of the head section to minimise the exposure to combustion breakout. This was subsequently revised in April 1994 to inspect for abnormal liner distress as a guide to developing head section break-up. Since then an RB211-524 engine experienced head section break-up which resulted in combustion breakout at engine top dead centre and although the degree of core engine distress was similar to previous incidents, greater than anticipated secondary distress of the power plant was experienced. As a consequence of further work we are now in a position to define enhanced inspection techniques by direct borescope of the head section. In addition it is necessary to reduce the inspection threshold and revise the acceptance criteria. ENGINE - COMBUSTION SECTION - INSPECTION OF FRONT COMBUSTION LINER HEAD SECTION AND METERPANEL ASSEMBLY FOR POTENTIAL FAILURE - ALERT NON MODIFICATION SERVICE BULLETIN - MOD.72-AB482Printed in Great Britain



# RB.211−72−AB482 Page 1 of 12 Jul.21/95 Jul.28/03In November 1994 an RB211-524G engine experienced combustion flame breakout as a result of meterpanel circumferential failure leading to a local traverse shift. Following this failure Non-Modification Service Bulletin 72-B114 (see 1.F. References) was issued to recommend a borescope inspection of the combustion liner to check for heatshield displacement and fuel spray nozzle disengagement. Since that date a further two cracked meterpanels have been detected by borescope inspection and both involved combustion liners where the meterpanel had not been replaced at previous rework. Since meterpanel displacement could result in similar powerplant secondary distress were it to occur near to the top of the engine, it is also necessary to instruct borescope inspection at specific lives.

This NMSB combines the intent of NMSB 72-9768 and NMSB 72-B114 for RB211-524G/H engines and includes the revised borescope technique and frequency. The relevant Maintenance Manuals will be revised to reflect the new acceptance criteria. Consequently NMSB 72-B114 is to be cancelled and NMSB 72-9768 revised to delete reference to RB211-524G and 524H engine marks. Since the original issue of this NMSB, considerable data has been gathered with regard to the level of strut cracking subsequently experienced on previously Nicrobraze repaired head sections. This shows that the level of subsequent strut cracking is much reduced and that the requirement for initial and repeat inspections can be relaxed. In January 1996 another RB211-524G engine experienced meterpanel failure and combustion flame breakout, even though it had been inspected in accordance with this NMSB only a short time previously. As a result it is apparent that the existing method of inspection, utilising the routine borescope access ports, cannot be relied upon to prevent further failures. Consequently it is necessary to specify a revised method of inspection giving direct access to the meterpanel. In March 1997 another RB211-524H engine experienced hot gas escape as a result of meterpanel failure. This engine had achieved 1278 cycles since new. It is therefore necessary to reduce the inspection threshold for meterpanels not previously repaired. In March 1997 an RB211-524D4 engine experienced combustion flame breakout as a result of combustion liner meterpanel failure. The affected engine was one of a small number (17) to feature a combustion liner to the same basic standard (SB RB211-72-7998) as that fitted to all RB211-524G/H engines. Although Operators have been inspecting these engines to NMSB 72-B114, this did not detect the latest incident. Revision 5 of this NMSB therefore included RB211-524D4 engines within its effectivity. A small number of RB211-524B4 engines also incorporate the same basic standard of combustion liner (SB RB211-72-7998) as that fitted to RB211-524G/H engines. Although no significant meterpanel cracking has been seen in this engine mark, significant head break-up has been experienced on a number of occasions, albeit at higher cyclic lives. This NMSB therefore also includes RB211-524B4 engines within its effectivity.Printed in Great Britain



# RB.211−72−AB482 Page 2 Jul.21/95 Jul.28/03The SB RB211-72-7221 standard of combustion liner head section has an identical construction to the SB RB211-72-7998 combustor and service experience has revealed it to suffer from head section break-up in an identical manner. While NMSB RB211-72-9768 instructs inspection for secondary damage this has not succeeded in identifying head break-up in all cases. Revision 6 of this NMSB therefore included RB211-524B-02, 524B4, 524C2 and 524D4 engines incorporating SB RB211-72-7221 within its effectivity for head break-up only. Revision 7 further included RB211-524B2 and 524B3 engines incorporating SB RB211-72-7221 within its effectivity for head break-up only. There is no requirement to inspect meter panels for combustors to pre SB RB211-72-7998 standard. Revision 8 of this NMSB was issued to clarify at what interval the head section should be inspected following repair to FRS5367. The original issue of this NMSB was written with the intent that the nicrobraze repair, FRS5367, be applied to all 18 head section struts. Rolls-Royce have been made aware that sometimes the repair is only applied to those struts that are found to be cracked. FRS5367 has therefore been re-issued to include the instructions to mark the combustion liner head section after repair with either FRS5367/A or FRS5367/B. FRS5367/A indicates that not all of the struts have had the Nicrobraze repair. FRS5367/B indicates that the nicrobraze has been applied to all head section struts. Section 1. C. (1) of NMSB RB211-72-B482 has been amended accordingly. In August 2002 an RB211-524B4 engine suffered a combustion case burnthrough as a result of combustor head break-up. The combustor head had been inspected in accordance with this NMSB only 228 cycles prior to the event. Revision 9 of this NMSB is therefore issued to reduce the inspection interval of RB211-524B-02, 524B2, 524B3 and 524B4 engines that have not been repaired in accordance with FRS5367/B, from 400 cycles to 200 cycles, in line with all other engine marks. C. Compliance

ALERT This (Non-Modification) Service Bulletin is declared Mandatory by the United Kingdom Civil Aviation Authority (CAA) and is subject to the incorporation requirements of a UK Civil Aviation Authority Airworthiness Directive (AD).

(1) Head section (a) Not previously repaired (i) RB211-524C2, 524D4, 524G and 524H engines:Printed in Great Britain



# RB.211−72−AB482 Page 3 Jul.21/95 Jul.28/03Inspect in accordance with 3. Accomplishment Instructions (A) at between 1400 and 1600 cycles since new and repeat at intervals not exceeding 200 cycles subject to 1. E. Acceptance Limits. For combustion liners in excess of 1600 cycles since new, which have not been previously inspected to NMSB RB211-72-B482, inspect within 100 cycles.

(ii) RB211-524B-02, 524B2, 524B3 and 524B4 engines: Inspect in accordance with 3. Accomplishment Instructions (A) at between 3000 and 3200 cycles since new and repeat at intervals not exceeding 200 cycles subject to 1. E. Acceptance Limits. For combustion liners in excess of 3200 cycles since new, which have not been previously inspected to NMSB RB211-72-B482, inspect within 200 cycles. (b) Repaired in accordance with FRS5367/B when the head section was last repaired. (i) RB211-524C2, 524D4, 524G and 524H engines: Inspect in accordance with 3. Accomplishment Instructions (A) at between 1800 and 2200 cycles since FRS5367/B was carried out and repeat at intervals not exceeding 400 cycles subject to 1. E. Acceptance Limits. For those head sections which exceed 2200 cycles since FRS5367/B, and have not been previously inspected to NMSB RB211-72-B482, inspect within 200 cycles. (ii) RB211-524B-02, 524B2, 524B3 and 524B4 engines: Inspect in accordance with 3. Accomplishment Instructions (A) at between 3000 and 3200 cycles since FRS5367/B was carried out and repeat at intervals not exceeding 400 cycles subject to 1. E. Acceptance Limits. For those head sections which exceed 3200 cycles since FRS5367/B, and have not been previously inspectd to NMSB RB211-72-B482, inspect within 200 cycles. (c) Repaired by means other than FRS5367/B when the head section was last repaired. (i) RB211-524C2, 524D4, 524G and 524H engines:Printed in Great Britain



# RB.211−72−AB482 Page 4 Jul.21/95 Jul.28/03Inspect in accordance with 3. Accomplishment Instructions (A) at between 500 and 700 cycles since last head section repair and repeat at intervals not exceeding 200 cycles subject to 1. E. Acceptance Limits. For combustion liners in excess of 700 cycles since repair, which have not been previously inspected to NMSB RB211-B482, inspect within 100 cycles. (ii) RB211-524B-02, 524B2, 524B3 and 524B4 engines: Inspect in accordance with 3. Accomplishment instructions (A) at between 2000 and 2200 cycles since last head section repair and repeat at intervals not exceeding 200 cycles subject to 1. E. Acceptance limits. For head sections in excess of 2200 cycles since repair, which have not been previously inspected to NMSB RB211-72-B482 inspect within 200 cycles.

NOTE : For an installed Front Combustion Liner that is subject to NMSB RB211-72-B482: If the operator can confirm with the relevant Overhaul Base or Repair Vendor that the Nicrobraze repair FRS5367, has been applied to all 18 struts, then this is equivalent to FRS5367/B.

NOTE : Head sections repaired by replacement of all 18 struts in accordance with FRS6548 are considered as equivalent to fitting a new head section for inspection purposes. (2) Meterpanel assembly RB211-524D4, 524G and 524H engines incorporating SB RB211-72-7998 (not 524B4) (a) Not previously repaired Inspect in accordance with 3. Accomplishment Instructions (B) at between 1000 and 1200 cycles since new and repeat at intervals not exceeding 400 cycles subject to 1. E. Acceptance Limits. For meterpanels in excess of 1200 cycles since new, and not previously inspected to NMSB RB211-72-B482, inspection is required within 50 cycles. For those operators who do not use RB211-524H rating at any time, the inspection threshold may be increased to between 1800 and 2000 cycles.Printed in Great Britain



# RB.211−72−AB482 Page 5 Jul.21/95 Jul.28/03(b) Previously repaired Inspect in accordance with 3. Accomplishment Instructions (B) at between 500 and 700 cycles since last repair, if meterpanel not replaced by new, and repeat at intervals not exceeding 400 cycles subject to 1. E. Acceptance Limits. For meterpanels in excess of 700 cycles since last repair and not previously inspected to NMSB RB211-72-B482, inspection is required within 50 cycles.

NOTE : For meterpanels previously inspected in accordance with 1. C.(2) and placed on a 200 or 400 cycle repeat interval, these must be re-inspected within 100 cycles or the next scheduled inspection, whichever is the sooner, and assessed against the latest Aircraft Maintenance Manual Acceptance Limits for Row 3 and 4 cracking. Alternatively, the crack mapping records from the previous inspection should be reviewed against these limits and re-inspection instructed accordingly. D. Approval The content of this Non-Modification Service Bulletin was approved by a representative of the United Kingdom Civil Aviation Authority (CAA) on Jul.18/95, and re-approved on Sep.26/95, Feb.28/96, Sep.16/96, Apr.11/97, May 9/97, Oct.26/98, Jul.26/99, Nov.12/01 and Jul.16/03. E. Acceptance Limits Refer to Aircraft Maintenance Manual, 72-00-00, Inspection/Check.

NOTE : Missing or displaced head section or meterpanel material is not acceptable unless associated with bleed strut support tube release.

F. References (1) Rolls-Royce RB211 Service Bulletins: 72-7221 Front combustion liner flexible mounting (hairpin section) and improved cooling

72-7998 Phase 2 low emission front combustion liner with Parker Hannifin fuel spray nozzles 72-9670 Improved package 1 combustion liner head in C263 material and local thickened diffuser walls around struts 72-9764 Improved phase 2 combustion liner with strengthened head section in C263 materialPrinted in Great Britain



# RB.211−72−AB482 Page 6 Jul.21/95 Jul.28/03(2) Rolls-Royce RB211 Non-Modification Service Bulletins: 72-9768 Inspection of front combustion liner head section for possible break-up 72-B114 Inspection of meterpanel assembly for potential failure (3) Rolls-Royce Repair Schemes: FRS5367 Nicrobraze repair combustion liner head section cracking FRS6548 Repair combustion liner head section by fitting new bleed struts (4) Aircraft Maintenance Manual: (a) 72-00-00, Inspection/Check (b) 73-11-06, Fuel Spray Nozzle, Removal/Installation

2. Material Information

None.Printed in Great Britain



# RB.211−72−AB482 Page 7 Jul.21/95 Jul.28/033. Accomplishment Instructions A. Inspect for head section break-up at fuel spray nozzle positions 2, 3, 16 and 17 in accordance with Aircraft Maintenance Manual, 72-00-00. Make an inspection of the Diffuser Case Bleed Struts, Front Section Outer Liner and Inner Liner. The following alternative procedure may be used subject to Operator preference: (1) Remove one of the two rearmost fuel spray nozzle retaining bolts (typical IPC Ref. 73-11-05, 01-012) in accordance with Aircraft Maintenance Manual, 73-11-06, Fuel Spray Nozzle, Removal/Installation from a FSN position. (2) Using a 4mm. (0.157in.) flexible borescope, or suitable alternative inserted through the bolt hole and corresponding clearance hole in outer diffuser case (Fig 1), inspect bleed struts in region between outer diffuser case and front section outer liner. Bleed struts either side of fuel spray nozzle can be inspected. With flexible borescope further inserted, using the HP compressor OGV's as a visual reference, it can be manipulated to give a view of the bleed struts between front section inner and outer liners. (3) Repeat (2) at other 3 FSN positions by either removing further FSN retaining bolts or by further insertion of flexible borescope from first FSN position. (4) On completion of (2) and (3) remove borescope carefully to avoid damage. Re-install fuel spray nozzle retaining bolts in accordance with Aircraft Maintenance Manual, 73-11-06, Fuel Spray Nozzle, Removal/Installation. (5) In addition to the above, inspect the head section using a 90 degree view rigid borescope (Fig 1). With this inserted through the normal combustion section access ports and passing right through the combustion liner into the annulus between liner inner wall and combustion inner casing, sections of the head inner liner are visible if they have become displaced towards the combustion inner casing. Similarly, displaced bleed struts may also be visible. On withdrawing the borescope, it is also possible to view between the liner outer wall and combustion inner casing outer barrel. Through this annulus, cracking and lifting of the front section outer liner rear of the fuel spray nozzles may be visible. B. Inspect for meterpanel cracking in the region of Rows 3 and 4 slots (Fig 2) in accordance with the following procedure: Record cracks observed within and between Rows 3 and 4. Note Fig 3 provides a suitable meterpanel section which can be used for mapping cracks. All inspection findings together with engine serial number and meterpanel cycles at inspection must be passed to the local Rolls-Royce office.Printed in Great Britain



# RB.211−72−AB482 Page 8 Jul.21/95 Jul.28/03(1) Remove two diametrically opposite fuel spray nozzles in accordance with Aircraft Maintenance Manual, 73-11-06, Fuel Spray Nozzles, Removal/Installation. Positions 4 and 14 are suggested. (2) Insert guide tube HU80283 through FSN port to enable flexible borescope to be inserted in annulus between combustion liner head section inner wall and meterpanel inner attachment (Fig 2). (3) Using suitable flexiscope 8mm. diameter, 1.5 metres minimum length, near focus, forward facing, 60 degree field of view, mark its outer sheath in increments of 115mm. (4.5in.) to represent the arc between FSN's. (4) Insert flexiscope into guide tube and inspect for meterpanel cracking between first two adjacent FSN positions. Inspect for cracking of small ligaments between individual circumferential slots in Row 4 (Fig 2). By manipulating flexiscope also inspect for similar cracking in Row 3 and for any cracks linking Rows 3 and 4 (Fig 2). (5) Repeat inspection procedure by further inserting the flexiscope to the next mark until 9 FSN positions have been covered. By removing the flexiscope, rotating the guide tube and re-inserting the flexiscope it is possible to inspect 9 FSN positions either side of the nozzle actually removed. (6) Repeat inspection procedure at both removed FSN positions until meterpanel has been inspected around 360 degrees, i.e. all 18 FSN positions have been viewed from both directions to ensure adequate Row 3 slot inspection. (7) On completion of inspection procedure, remove flexiscope and guide tube and then re-install removed FSN's in accordance with Aircraft Maintenance Manual, 73-11-06, Fuel Spray Nozzle, Removal/Installation.

NOTE : Alternative methods to the above may be used subject to (i) local airworthiness authority approval and (ii) achieving a satisfactory inspection of the Row 3 and 4 slots over the complete circumference of the meterpanel.Printed in Great Britain



# RB.211−72−AB482 Page 9 Jul.21/95 Jul.28/03Front combustion liner showing typical features and borescope access for the head section break-up inspection Fig.1Printed in Great Britain



# RB.211−72−AB482 Page 10 Jul.21/95 Jul.28/03Front combustion liner head section showing flexible access for meterpanel inspection and view through flexiscope showing rows 3 and 4 of meterpanel Fig.2Printed in Great Britain



# RB.211−72−AB482 Page 11 Jul.21/95 Jul.28/03Typical meterpanel quadrant for mapping cracks Fig.3Printed in Great Britain



# RB.211−72−AB482 Page 12 Jul.21/95 Jul.28/03