# 0 Pratt & 

# Whibley A Un ited Technologies Company 

# SERVICE BULLETIN

EN GI N E - ROTOR ASSEM BLI E S. HIGH PRESSURE C O MPRESSOR (HPC) ROTOR NUTS - RE PLACEMENT OF, TO RE DUC E R I SK OF STRESS CORROSIO N AT TITANIUM ROTO R DISKS MODEL APPLICA TI O N PW6122A, PW6 124 A BULLET IN ISSUE SEQUENCE PW6000 Series 72 -4 6 ATA NUM B ER 72-3 5-00

UTC/P&W PROPR I ETARY INFORMATION Th i s document i s the property of Un ited Technologies Corporation- Pratt & Whitney (UTC/P&W). You may not possess . u se . copy or discl ose this document o r any informatio n in it. for any purpose , including without limitati on to des i gn . manufacture , or repair parts , or obtai n FAA or other government approval to do so . without UTC / P&Ws express w ritten permi ss ion. Neit her receipt nor posse ssion of thiS document alone , from any source . constit utes such perm i ss i on . Possess ion , use , copying o r disclosure by anyone w ithout UTC/ P&Ws express written permission is not authorized and may resu lt in criminal and/or civi l lia b ili ty. Not subj ect to the EAR per 15 C. F
.R. Chapter 1 , Part 734 .3(b)(3). Compli a nce Category 6 P&W Distribution Code 2645 M a rc h 5/15
Published i n United States of America 

# PW6ENG 72-46 Page 1 of 12

# Pratt & 

# Whitney A United Techn ol o gies C ompany Summary Th e purpose of this Service Bulletin is to replace High Pressure Compressor (HPC) rotor nuts. T h e replacement of th e silver plated rotor nuts with non-s i lve r plated nuts is in 

### order to prevent stress corrosion on t itanium disks
. During engine overh aul , cracks have been found on 7th stage compressor rotor disk rear wing in itiating from the corrosion area . Stress corrosion was found to be caused by interaction between the titanium disk material and silver plating w h ich is used as a lubricant on the rotor nut threads
. Due to this recent shop finding , all silver plated rotor nuts inside the roto r drum will be r eplaced with non-silver plated nuts to prevent corrosion attack and cracking. Plannin g Information Effectivity Data Engine Mode l s Applicable PW6122A , PW6124A Engine Serial Nos. P318104 thru P318140" " This estimate of engine serial numbers will be revised , if necessary, when parts are installed i n engines at Pratt & Whitney. NOTE : The engine serial number effectivity data and its related engine model identification contained in this Service Bulletin are taken from the records of part(s) i ncorporation during initial manufacture
. After initia l engine m anu facture. but before final delivery, P&W may change part(s) in the engine or change the model i dentifi cation of the engine. Such action is recorded on FAA337 forms. To find Service Bulletin PW6ENG 72-46 models that are applicable , the owner/operator of the engine must compare the Service Bulletin List supplied with the engine as sen t from P&W and the List of Ch anges incorporated at the Airframe r from FAA337 forms to the Service Bulletin PW6ENG 72-46 Eff ect ivity sectio n. Concurrent Requirem ents Th ere are no concurrent requ irements. Reason 1. Prob lem : Du ring scheduled engine overhaul of the HPC rotor. cracking of 7t h stage com pressor rotor disk rear wing has bee n found in areas of bolt holes. 2 . Cau se : Stress corrosion caused by a reaction of silver plating residue from the rotor nut threads with the ti tanium disk material in presence of sodium , su lfur and chloride at a specific temperature range . 3. Solutio n : Silver plated rotor nuts of all HPC rotor stages to be replaced by new non-silve r plated nuts du ring shop visit to elim i nate the potential for stress corrosion
. Description Re place t he rotor nuts for the bolted joint between the HP C stages 6 to 7, 7 to 9 and 9 to 11 drum assembl ies.

March 5 / 15 

# PW6ENG 72-46 UTC / P&W PROPR I ETARY INFORMATION Subject to the restrictio ns on the cover or first page. Not Subject to the EAR per 15 C.F
. R
. Chapter 1 , Part 734
. 3(b)(3). Page 2

# Pratt &

# Whimey A Un ited Techn ol ogies C ompany The tightening procedure for the rotor nuts at the three joints is changed to a combined torquing and angle of turn procedure. NOTE: The new rotor nut standard is made of the same base material , but is not silver plated on the in ternal threads. The new rotor nuts have the same spline drive outer geometry. Complian ce Category 6 Do when the subassembly (i.e. modules , accessories , components , build groups) is disassembled sufficiently to give access to the changed part and to all changed spare parts. Approval Data The part number cha n ges and/or pa rt ch anges specifi ed in the Material Information section and Accomplishment I nstructions of this Service Bulletin agree with the applicable Federal Aviation Regulations and are FAA-Approved for the engine model(s) given. The aircraft Type Certificate (TC) holder has been informed of this change. W eight Data No Ch ange. Electrica l Load Data Not App l icable
. Software Accomplishment Summar y Not Applicable. References 1. Turbojet Engine Standard Practices Manual , Part No. 585005. 2. PW6122A and PW6124A Turbofan Engines , Illustrated Parts Catalog , Part No
. 5407766. 3. PW6122A and PW6124A Tu rbofan Eng ines , Engine Manual , Part No
. 5407764. Publicat ions Changed PW6122A and PW6124A Turbofan Engines , Illustrated Parts Catalog , Part No. 5407766
. 72-35-00 , Figure 1 , 2 , and 4 PW6122A and PW6124A Turbofan Engines , Engine Manual, Part No. 5407764. Interchangeability O ld an d new parts are interchangea bl e only in sets. Informat ion in the Appendix Alternate Accomplishment Instructions (No) Progression Charts (Yes) Added Data (Yes) Revision to Table of Li mits (No) Inspecti on Procedures (No) March 5/15 

# PW6ENG 72-46 UTC/P&W PRO PRIE T A RY I NFOR MA T I ON S u bject to the res tr ictions on the cove r o r first page . Not s ubject to the EAR per 15 C.F.R Chapter 1 , Part 734.3(b)(3). Page 3

# Pratt & Whitney A United Technologies Company Material Information Material - Cost and Availability 1 . Part prices were not available at the time of SeNice Bulletin publication
. Contact Pratt 

### & Whitney Spares Management & Logistics for firm quotations. 2 . Part availability information is provided in material data Instructions- Disposition. Industry Support Program Not Applicable
. The material data that follows is for each engine. NOTE: It i s possible to use the Chapter/Section and Figure/Item reference number shown below the old part number to find the part in the Illustrated Parts Catalog. CAUTION: THE FOLLOWING MATERIAL DATA TABLE(S) ARE ORGA NIZED BY ILLUSTRATED PARTS CATALOG
. ALL PARTS IN THE TABLE(S) MAY OR MAY NOT BE APPLICABLE TO ALL THE ENGINE MODELS SHOWN IN THE TABLE HEADING
. YOU MUST REFER TO THE APPROPRIATE ILL USTRATED PARTS CATALOG FOR ENGINE MODEL APPLICABILITY USING THE OLD PART NUMBER ( PN ) AND CATALOG SEQUENCE NUMBER. FA ILUR E TO INSTALL THE PART(S) I N THE CORRECT ENGINE MODEL MAY RESULT IN A CONFIGURATION THAT IS NOT FAA APPROVED
. T he materi al data that follows is for each engine. For PW61 22A , PW6124A Engines :

New PN Qty Estimate of Unit Keyword Old PN Instructions - Price($) Disposition 1B2647 24 

# .. NUT- OPTION 4301682 (2)(A)(C1 )(0 1 ) (72-35-70-01-030) 1 82647 18 

# .. NUT- OPTION 4301682 (2)(A)(C1 )(0 1) (72-35-70-01 -21 0) 1B2647 18 * NUT- OPTION 4301682 (2)(A)(C1 )(0 1) (7 2-35-70-02-170) 1B2647 18 * NU T- OPTION 4301682 (2)(A)(C 1 )(0 1) ( 72-35-70-04-180) Modification and Spares Information Estimated part prices are provided when they are available at time of publication
. The Estimate of Un it Price is only for planning purposes and does not constitute a firm quotation. An asterisk(*) is shown where part pricing information was unavailable
. In either case . contact Pratt 

### & Whitney Spares Management 

### & Logistics for firm quotations. Parts Modification Conditions ( 2) The new part is a replacement part only, and cannot be obtained by modification of the old pa rt. Spare P arts Availability March 5/15 

# PW6ENG 72-46 UTC/P&W PROPR IE TARY INFORMATION Subject to the restrictions on the cover or first page. Not Subject to the EAR per 15 C.F.R. Chapter 1 , Part 734.3(b)(3). Page 4

# 0 A Un ited Technologies Company 

# Pratt &

# Whibley (A) The new part is available. (C1) The old part will continue to be supplied for use at other l ocations. (01) Nut Option, PN 182647 , consists of a Insert, PN 182643 , or PN 182644
. or 182645 , or PN 182646. Vendor Services or Special Components/Materials Not Applicable. Material Data for Each Spare Engine The material for each spare engine is as stated in the preceding material informat ion section. Reidentified Parts Not Applicable. Necessary Tools Tool No. 8059093000 New Support Equ ip ment that is necessary Name Manufacturer ST W rench Atlas Copco or Wrench with comparable specifications Other Material Information Data Not Applicable
.

March 5/ 15 

# PW6ENG 72-46 UTC/P&W PROPRIETARY INFORMATION Page 5 Subject to the restrictions on the cover or first page. Not subject to the EAR per 15 C.F.R Chapter 1 , Part 734.3 (b)(3).

# Pratt & Whitne y A Un ite d T echn ol ogies C ompany Accomplishment In structions 1. Replace the 6th. 9th
. and 10th stage Nut-Option s , PN 4301682 , with PN 182647. At eng i ne as semb ly make the following changes to th e engine m anual procedures. 2. In Reference 3 , Engine Manu al , Chapter/Section 72-35 -70 , Assembly-07 : Replace the follow ing step: ( 3)( b) Apply An ti-Sei ze Paste Compound P06-054 (PWA36246-2) to the threads of the 18 p ins [3]. With : (3) ( b) Apply Ant i-Seize Pa ste Co mpound P06-0 54 ( PWA36246 -2) to threads of the nuts [1] and the surface of the nuts [1] which will be in contact with the rotor flange. Re place the following step : (3)(g ) To r que the nuts [1] with the Fixture detail torque adapter and a torque wrench by two steps that follow : ( 3)(g) (1) Torque the nuts [1] in by the torque sequence to 57- 631bf-in (6.440- 7 . 118 N.m). NOTE : Do not use a click-stop torque w rench
. Use only a torque wrench with drag indi cator. (3) (g )( 2) To rq ue the nuts [1] by the torque sequence to 71- 78 1bf-in (8.022- 8 .813 N.m). ( 3)(g )(3) Check the torque of all the nuts [1] in clockwise direction. With : (3)(g) Torque the nuts [1] with the Fixture detail torque adapter and the too l 8059093000 ST Wrench by th e steps that follow : (3)( g)( 1 ) Torqu e the nuts [1] in by torque sequence to 71. 7 -771bf - in (8. 1 - 8.7 Nm)
. ( 3)(g )(2 ) Check the torque of all the nuts [ 1] in clockwise direction. 3. In Reference 3 , Engine Ma nu al , Chapter/Section 72-35-70, Assembly-19: Delete the follow ing step : (6 )(d) A pply Anti-Seize Pa ste Compound P06- 054 (PWA36246-2 ) to the threads of the 18 p i ns on t he front of the 9th stage rotor assemb ly. Re p lace the follow i ng step : ( 8) Install the 18 nuts [41] to the HPC rotor assembly as follows. See Figure 1005 (Sheet 1) and Fi gure 1005 (Sheet 2)
. ( 8)(a) Insta ll the PWA 104871 Guid e Fixtu re to the 9th stage rotor assembly [21]. ( 8)( b) I n stall the 18 nuts [41] with the PWA 104819 Nu t Starter to the HPC rotor assembly
. ( 8)(c) Torque the 18 n uts (41 ] with the PWA 104820 Torque Adapter and the PWA 104873 Gu ide Pin to 60 lb-in (6.8 N .m) by the torque sequen ce. (8)(d) Torque the 18 nuts [41] again by t he step above to 260.2 lb- in (29.4 N .m) by the torque sequence. ( 8)(e) Check the torque of all of the 18 nuts [41]. ( 8)(f) Remove the Torque Adapter, t he Pi n , and the Fixtu re. March 5 / 15 

# PW6ENG 72 -46 UTC/P&W PROPR I ETARY INFORMATION Subject to the restrictions on the cover or first page. Not Subject to the EAR per 15 C.F. R. Chapter 1 , Part 734.3(b)(3). Page 6

# 0 A United T ech nologies Co mpany 

# Pratt & 

# Whibley
With: (8) Install the 18 n uts [41] to the HPC rotor assembl y as follows. See Figure 1005 (Sheet 1) a n d Figure 1005 (Sheet 2). (8)(a) Insta ll the PWA 104871 Guide Fixture to the 9th stage rotor assembly [21]. (8)(b) Apply Anti-Seize Paste Compound P06-054 (PWA36246-2) to threa ds of the nuts [41] a nd the surface of the n uts [41 ] which will be in contact with the rotor flange
. (8)(c) Install the 18 nuts [41 ] with the PWA 104819 Nut Starter to the HPC Rotor Assembly. (8)(d) Torq ue the nuts (41] with the PWA 104820 To rque Adapter and the PWA 104873 Guid e Pin and the tool 8059093000 Wrenc h to 84.1 - 92.9 lbf-in (9.5 - 10.5 Nm) by the torque sequen ce. (8)(e) Torque the 18 nu ts [41 ] again by the step above to 246 .9-272.6 lbf-in (27.9- 30.8 Nm) by the torque sequen ce. NOTE : After the pre-torque steps (d) and (e) do not loose all nuts at the sa me time. Loose and tighten finally only one nut at th e sa m e time. ( 8)(f) Tighten each nut [41] finally with the too l 8059093000 ST Wrench by the steps that follow : (8)(f)(1) Loose one nut [41] at a time in torque sequence while maintaining all others tight and ensure that nut is separated from f l ange . (8)(f)(2) Torque subsequently nut [41] and meas ure run -on torque (torque requ ired to turn nut due to self-locking fea ture of nut). (8)(f)(3) Record run-on torque of each nut [4 1]. Minimum allowable run-on torque is 6.5 lbf - in (0.735 Nm). Otherw ise rep lace nut [41]
. (8)(f)(4) Torque nut [41] to 26 .55- 44.251bf-in (3- 5 Nm) plus the run-on torqu e noted for each nut. Ensure that nut i s in con tact with flang e. (8)(f)(5 ) Then, apply with the PWA 104820 Torque Ad apter and the tool 8059093000 W rench angle of turn of 53 - 57 deg rees. (8)(f)(6) Measure and record achieved tighten ing torque against angle of turn . ( 8)(f)(7) After angle of turn is applied , make sure that f i nal torque is between 221 - 292 lbf-in (2 5 - 33 Nm). Otherwise change nut and repeat steps (8)(f)(1) - (8)(f)(7) to reach the required torque range . (8)(f)(8) Move to next bolt in torque sequence until all nuts a re tightened. (8)(g) Remove the Torque Adapter, the Pin , and the Fixture. De l ete the fo ll owing step: ( 14)(c) Apply Anti-Seize Paste Comp ound P06-054 (PWA 36246-2) to the threads of the bolts [71]. Replace the following step : (15) Install the 18 nuts [81] between the 7th stage rotor assembly [61] and 8th stage rotor assembly [5 1 ] as follows
. See Figure 1010
. (1 5)(a) Install the PWA 104871 Gu ide Fixture to the 7th stage rotor assembly [61]. March 5/15 

# PW6ENG 72-46 UTC/P&W PROPR I ETARY I NFOR MAT I ON Subject to the rest r ictions on the cove r or first page . Not subject to th e EAR per 15 C
. F.R Chapter 1 , Part 734.3(b)(3). Page 7

# Pratt & 

# Whitney A United Technologies Company (15) ( b) Install the 18 nuts [81] with the PWA 104825 Torque Adapter and the PWA 104873 Guide Pin. (15)(c) Torque the 18 nuts [81] w ith the PWA 104820 To rque Adapter and the Pin to 60 !b-in (6.8 N.m) by the torque sequence. ( 15) (d) Torque the nuts [81] again with the PWA 104820 Torque Adapter and the Pin to 260
.2 lb-in (29.4 N.m) by the torque sequence . (1 5)(e ) Check the torque of all of the 18 nuts [81 ]. ( 15)(f) Remove the Fixture. W ith : ( 15) Install the 18 nuts [81] between the 7th stage rotor [61] and the 8th stage rotor assembly [51] as fo ll ows. See Figure 1010. (1 5)(a) Install the PWA 104871 Gu ide Fixture to the 7th stage rotor assembly [61]
. (1 5)( b) Apply Anti-Se ize Paste Compound P06-054 (PWA36246-2) to threads of the nuts [81 ] and the surface of the nuts [81] which will be in contact with the rotor flange. (1 5)( c) Install the 18 nuts [81] with the PW A104825 Torque Adapter and the PWA 104873 G ui de Pi n . ( 15 }(d ) Torque the 18 nuts [81] with the PWA 104820 Torque Adapter and the Pin and the 8059093000 ST Wrench to 84.1 - 92.9 lbf-in (9.5 - 10
.5 Nm) by the torque sequence. ( 15)(e) Torque the 18 nuts [81] again by the step above to 246.9- 272.6 lbf-in (27
. 9- 30
.8 Nm) by the torque sequence . NOTE : Afte r the pre-torque steps (d) and (e) do not loose all nuts at the same time. Loose and tighten finally only one nut at the same time
. ( 15)(f) T ighten each nut [81 ] finally with tool8059093000 ST Wrench by the steps that fo ll ow: ( 15)(f) ( 1 ) Loose one nut [81] at a time in torque sequence while maintaining all others tight and ensure that nut is separated from flange. ( 15)(f)(2) Torque subsequently nut [81] and measure run - on torque (torque required to turn nut due to self-locking featu re of nut). ( 15) (f) (3) Record run-on torque of each nut [81). Minimum run-on torque is 6.5 lbf - in (0. 735 Nm )
. Otherwi se replace nut [81 )
. ( 15)(f) (4) Torque nut [81] to 26.55- 44
.251bf-in (3 - 5 Nm) plus the run-on torque noted for each n ut. Ensure that nut is i n contact w ith flange
. ( 15)(f) (5) Then , apply with the PWA 104820 Torque Adapter and the tool 8059093000 Wrench angle of turn of 53 - 57 degrees
. ( 15)(f) (6) Measure and reco rd achieved tightening torque against angle of turn. ( 15)(f) (7) After angle of turn is applied , make sure that final torque is between 221.0 - 301.0 lbf-in (25- 34 Nm). Otherwise change nut and repeat steps (15)(f)(1)- ( 15)(f)(7) to reach the requi red torque range. (1 5)(f) (8 ) Move to next bolt in torque sequence until all nuts are tightened. ( 15)(g ) Remove t he Fixt ure. Ma rch 5/1 5 

# PW6ENG 72-46 UTC/P&W P ROPRIETARY INFOR MATI ON Subject to t he res trictions on the cover o r first page. Not Subject to the EAR per 15 C.F.R. Chapter 1, Part 734.3(b)(3). Page 8

# 0 A United Technologies Company 

# Pratt &Whitney Replace the following Step : (19)(d) I nstall the 24 nuts [101] to the 6th rotor assembly as follows
. (19)(d)(1) Install the 24 nuts [ 101] to the rotor assembly (101]. (19)(d )(2) To rque the 24 nuts [101] to 57- 631bf-in (6.44 0- 7.118 N.m) by the torque sequence . NOTE: Use a torque wrench with drag indicator. (19)(d )(3) Torque the nuts [101] to 247- 273 lbf-in (27.907- 30.845 N.m) by the torque sequence . NOTE: Use a torque wrench with drag indicator. (19)(d)(4) Check the torque of the 24 nuts [101]. With: (19)(d ) Apply Anti-Seize Paste Compound P06-054 (PWA36246-2) to threads of the nuts [101] and the surface of the nuts [101] which will be in contact with the rotor flange. (19)(e) Install the 24 nuts [101] to the 6th rotor assembly [91]. (19)(f) Torque the 24 nuts [1 01 ] with tool 8059093000 Wrench to 84.1 - 92.9 lbf-in (9.5- 10.5 Nm) by the torque sequence. (19)(g) Torque the 24 nuts [101] with tool8059093000 Wrench again by the step above to 246.9 - 272.6 lbf-in (27.9- 30.8 Nm) by the torque sequence. NOTE: After the pre-torque steps (f) and (g) do not loose all nuts at the same time. Loose and ti g hten finally only one nut at the same time
. (1 9)(h) Tighten each nut [1 01] fina lly wit h tool 8059093000 ST Wrench by the steps th at follow: (19)(h)(1) Loose one nut [ 101] at a time in torque sequence while maintain i ng all others tight and ensure that nut is separated from flange. (1 9)(h )(2) Torque subsequently nut [1 01] and measure run-on torque (torque required to turn nut due to self-locking feature of nut). ( 19)(h)(3) Record run-on torque of each nut [101]. Min imum ru n-on torque is 6.5 lbf-in (0
. 735 Nm). Otherwise replace nut [101]. (19)(h)(4) Torque nut [101] to 26.55- 44.25 lbf-in (3 - 5 Nm) plus the run -o n torque noted for each nut. Ensure that nut is in contact with flange. (19)(h)(5) Then , apply angle of turn of 53- 57 degrees. ( 19)(h )(6) Measure and re cord achieved to rque against ang l e of turn. (19)(h)(7) After angle of turn is applied , make sure that final torque is between 221 .0 - 301.0 lbf-in (25- 34 Nm). Otherwise ch a nge nut and repe at steps ( 19) (h)(1) - (1 9)(h )(7) to re ach the required torque range. {19)(h)(8) Move to next bolt in torque sequence until all nuts are tightened.

March 5 / 15 

# PW6ENG 72-46 UTC/P&W PROPR IETARY IN FO RMAT ION Page 9 Su bject t o the restr ictions on the cover or first page . Not subject to the EAR per 15 C.F.R Chapter 1 , Part 734 .3(b}(3).4301682 NUT-OPT I ON REPLACE WITH 182647 (24 UN ITS }

65239 1 8

March 5/1 5 

# Pratt &

# Whitney A United Technologies Company

LOCATION OF T HE HPC ROTOR NUTS 72 -35-0 0 F IGURE 1, Sheet 1 4301682 NUT-OPTION REPlACE WITH 182647 ( 18 UNITS)



# PW6ENG 72-46 UTC/P&W PROPRIETARY INFORMATION Page 10 Subject to the re strictions on the cover or first page . Not Subject to the EAR per 15 C.F.R. Chapte r 1 , Part 734.3(b)(3)
.4301682 NU T-OPT ION REPLACE W IT H 182647 (1 8 UNITS ) 

# \

85239 1 9

March 5 /1 5 

# Pratt & 

# Whitney A Un ited Technologies Company

430 1 682 NUT-OPTION R EPLACE WI TH 182647 ( 1 8 UNI T S)

LOCATION OF THE HPC ROTOR NUTS 72-35-00 FIGURE 2 , Sheet 2 

# PW6ENG 72-46 UTC/P&W PROPRIETARY INFORMATION Subject to the restrictions on the cover or f i rst pag e. Not subject to the EAR per 15 C.F.R Chapter 1 , Part 734.3 (b)(3)
. Page 11

# Pratt & Whitney A Un ited Technologies Company Appendix Parts Progression To Show the Changed Part in Re l ation to Other Pa rts

8523917 Added Data
Revision No. Orig inal HPC ROTOR NUT CHART A Internal Reference Information Reference Document EC14MM013 4301682 ORIGINAL

182647 SB 72-46

Origination MTU Reference 3, Engine Manua l , Chapter/Section 72-35-70 , Assembly-07 and Assembly-19 , Revision 032 , dated A ug 01/15 is scheduled to incorporate th e assembly changes to this Service Bulletin and will take precede nce over the Service Bulletin. Numbe r values shown in parentheses adjacent to U.S. values are International System of units ( SI) equivalents.

March 5 / 15 

# PW6ENG 72-46 UTC/P&W PROPRIETARY INFORMATION Subject to the restrictions on the cover or first page. Not Subject to the EAR per 15 C .F.R. Chapte r 1 , Part 734.3(b)(3). Page 12