### DEPARTM ENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 !Docket No. FAA-2008-0808; Directorate Id e ntifier 2008- NE- 18-ADI RIN 2120-AA64 [4910-13-P]

Ainvorthincs s Directives; General E l ect ric Company CT58 T ur boshaft E ng ine s 

### AGENCY: Fede ral Aviation Adm ini s tration (FAA) , DOT. 

### ACTION: Notice of proposed r ulemak in g (NPRM). 

### SUMMARY: We propose to s up e rsede airworthiness directives (ADs) 2001- 1 8

- 06 and 2008 -22-16 , w hi c h apply to certain General E lectric Company (GE) C T58 turboshaft engines. ADs 200 1 -18-06 and 2008-22-16 re quire recalc ul at in g the liv es of life-limited rotating part s u s ing a Repetitive H eavy-L ift (RHL) multiplying factor and removal from
serv ice of part s that exceed the recalculated cyc li c or hourly life limit. This proposed AD
wo uld consolidat e ADs 2001- 1 8-06 and 2008-22 -16 , and further r educe the li fe capability of certain part s. We are proposing this AD to preve nt failure of lif e- limit ed rotatin g parts , uncontained part re lease, damage to the e ngi n e, a nd damage to th e aircraft. 

### DATES: We mu s t receive co mm ents on th is proposed AD by [INSERT DATE 60 DAYS AFTER DATE OF P UB LICATION I N THE FEDERAL REG ISTER]. 

### ADDRESSES: You may se nd comments , using the procedures found in 14 CFR 1 1.43 and 11.45 , by any o f the following methods:
• Federal e Rulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for s ubmitting comme nt s . • Fax: 202-493 -2251.• Mail: U.S. Department ofTransportation, Dock e t Operations , M-30 , West Building Ground Floor, Room W 1 2- 140 , 1200 New J ersey Avenue SE. , Washingto n , D C 20590.
• Hand Deliv e ry: Deliver to Mail address above between 9 a.m. a nd 5 p.m. , Monday through Frid ay, except Fed era l ho l idays. For service i nformation identifi ed in thi s p roposed AD, contac t Genera l Electric Company, GE Aviation , Room 285, One Neumann Way , C incinnati , OH, 45215; phone: 5 1 3- 552

- 3272; emai l : aviation.fleetsupport@ge.com. You may view thi s se rvice inf o m1ation at the FAA , Engine & Propeller Dir ectorate , 12 New E ng land Executi ve Park , Burlington, MA. For information on the availab ilit y of this mate rial at the FAA , ca ll 781-238-7125

. 

### Exa mining the AD Docket You may exami ne the AD docket on the Intern e t at http: //www. reg ulations.gov by
searc hing for and locatin g Docket No. F AA-2008-0808 ; o r in person at th e Dock et Management Facility between 9 a.m. and 5 p.m. , Monday through Friday, except Federal h o li days. Th e AD docke t contains this proposed AD , th e r egulatory eva luatio n , any comments received , and other inf ormation. The stree t address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES section. Comme nt s will be ava ilabl e in th e AD doc ket short ly afte r receipt. FOR FURTHER I NFORMATION CONTACT: Sanjana Murthy, Aerospace Enginee r , E ngi ne Ce rtification Office , FAA , Engine & Propeller Directorate , 12 New Eng land Executiv e Park , Burlington , MA 01803 ; ph o ne: 78 1- 238-7750; f ax : 781-238- 7 1 99; email: sanjana.murthy @ faa.gov.



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### SUPPLEMENTARY INFORMATION: Comments In vited W e in v ite yo u to se nd an y wri tt e n r e levant data , v ie w s, o r arg um e nt s a bout thi s prop ose d A D
. Se nd yo ur co mme nts to a n a ddress li s t e d und e r th e A DDR ESS ES sec ti o n . In cl ude " D oc ket No. FAA

- 2 0 08-0 8 08 ; Di r e c to ra te Ide ntifi e r 2008-N E -1 8-A D " at th e b eg inn i n g of yo ur co mm e n ts
. We sp ec ifi ca ll y in v ite c o mm e nt s o n th e ove ra ll regu lato r y , economic , e nviro nm e ntal , a nd en e rgy as p ec t s o f thi s propo s ed AD

. W e w ill con s id e r all comment s re c e ive d b y th e clo s in g dat e a nd m a y a m e nd thi s prop ose d AD b e cause of th ose c o mm e nt s . We w ill po s t all co mm e nt s we rec e i v e, w it h o ut c h a n ge , to http: // www .r eg ul a ti o n s.go v , includin g a n y p e rso nal informati o n yo u p rov id e . We w i ll
a ls o po s t a re p o rt s ummari z ing e a c h s ub s t a nti ve v erbal contac t w e rece ive about 

### thi s propos e d AD. 

### Discussion O n A u g u s t 24 , 200 I , we i ss u ed AD 200 1-18- 0 6 , Am e ndm e nt 39

- 1 2432 (66 FR 4 757 5 , Se pte m b e r 1 3 , 200 1 ), ( " AD 2 0 0 1

- 18- 0 6 " ) , a nd o n O c tobe r 20 , 200 8 , we i ss u ed AD 2008- 22 -1 6, A m e ndm e nt 39-1571 2 ( 7 3 F R 63 629 , Octob e r 2 7 , 2 008 ) , ( " AD 2008- 22-16 " ) , for C T 5 8 turbo s haft engine s . AD 2 00 1

- 18-06 require s th e u se of an RHL multipl y in g fac to r in ca lc ulatin g th e li ves o f lif e -limited rotatin g p a rt s u se d in RHL mi ss i o n s. A D 2008

- 22 -1 6 a ddre sse d a s h o rt fa ll in th e life capabi l ity o f co mp ress or s p oo ls
u s ed in RH L ope ra ti ons . W e i ss u e d A D s 20 01-18- 06 and 2 0 0 8- 22- 1 6 to pr eve nt c ra ck s i n rotating p art s th a t co uld r es ult in an un co nt a in e d e n g in e failure , d a mage to th e engin e, and dama ge to th e ai rc raft. 

### Actions Si nc e ADs 2001-18-06 and 2008-22-16 Were Issued S in ce we i s s u e d A D s 200 1

- 1 8-06 a n d 200 8- 22 -1 6 , GE up da t ed th e li fe limit s o f
c ompr esso r s poo ls . GE a lso up da te d h ow to ca lculate the li fe co n s umpti o n o f c o mpr esso r
3s pool s and o fli fe- limit ed rotating pa rts fl own in U tili ty operations. Th is upd ate r es ulted in ge ne ra ll y re du ced li ves fo r co mpressor spoo ls and all other li fe- limite d parts u sed in U tility o p erat io n s. 

### GE published th e ir updated lif e ca lc u lations for a ll life- lim ited parts in 

### G E Alert Service B ull eti n (ASB) No. CT58 

### SIB 72

- A0 1 62, Revi s ion 16 , dated January 7, 2015. 

### Relevant Service T nformation W e r ev iewed 

### GE ASB No. CT58 SIB 72-A0 1 62, Revi s ion 1 6, dated January 7 , 20 15. The service in fo rm ation describ es procedures for calculatin g l ife limits fo r th e affected life

- lim ited rotating p arts. T hi s service information is rea so n ably avai lab l e because the intere ste d part ies have access to i t through the ir n or m al co urse of busines s or
see ADDRE SSES for other ways to access thi s se r vice inf o rm atio n . 

### FAA's Determination We are propos in g this A D because we evaluated a ll the r e levant info1mation and determined the un safe co ndition described previous ly is li kely to ex is t or develop in o th er p roduc t s of the sam e type d es ign . 

### Proposed AD Requirements Thi s proposed A D wo uld reduce th e li fe limits of certai n co mpresso r spools u se d in a ll ope rat io n s a nd , throu g h impo s i tion o f a new li fing methodo logy, in c rease the li fe
cons umption o f a ll rotatin g parts used in Utili ty operatio n s . 

### Costs of Compliance We estim a t e that this proposed AD wo uld affect abo u t 60 e ngines in s talled on
a irc raft of U.S. reg is tr y . T h e average pro- ra t e d cos t of th e li fe- limited ro ta ting parts is $20,000. Th e ave r age labor r ate i s $85 per h ou r. Based on th ese fi g ures, we estimate th e cost ofthe propo se d AD on U. S. operat ors to be $8,7 15 ,000

.



### 4Authority for thi s Rul e makin g Titl e 49 ofthe U nite d States Co d e s p ecifi e s the FAA 's autho r ity to issue rules on aviation safety. Subti t le I , Sec ti on 106 , d es cribes the auth ority ofth e FAA Admin i strator. Subtitle VII , A v ia tion Program s, de sc ri b es in more detail th e s c o p e o f th e Agenc y's authori ty
. W e ar c i ss u i n g this rul em a kin g und e r th e authorit y d esc rib e d in S ubtitle V II , Part A , Subpart III , Section 44701 , " Gen e ra l re quirements. " Under that s ection , Congre ss charges th e FAA w ith promoting safe flight of civ il a irc r aft i n a ir com m erce by prescribin g reg ul a tion s for practice s, m e th o d s , a nd procedure s th e A dmini s trator find s
n e cessar y for s af e ty in ai r co mm e rc e. T hi s regu la tion i s withi n th e sco p e of th a t auth o rity because it addresses a n unsafe condition th a t i s like ly to e x i s t or d eve lo p on product s identified in thi s rul e making action. Regulato ry Findings We hav e d e termined that th i s propo se d AD w ould not h a v e fe derali s m implication s un de r Exe cuti ve Order 1 3 1 32

. Thi s pro po s ed AD wo uld n o t h ave a
s u bst a ntial direc t e ff ec t on th e Stat e s , on th e r e la tionship bet wee n the n a tion a l Governm e n t a nd th e State s , or on the di s tribution of power and r es p o n s ibilities among the
var io u s lev e ls or g ove rnment. For th e r eas ons discussed abov e , I ce rtif y that the prop ose d re gu lation: (1 ) I s n o t a " s i g ni ficant regulatory ac tion " under Executi ve Ord e r 1 2 866 , ( 2 ) l s n o t a ' · s ign i ficant ru le" und e r th e DOT Regula tor y Polici es and Procedur es ( 44 FR 11034 , F e bruary 26 , 1979), (3 ) Will not affect intrastate avi a tion in A laska to the extent tha t it justifies making a reg u la to ry di s tinction , and ( 4 ) Will n o t h av e a s ign ificant eco n o mi c impact , po s i ti ve o r n egati ve, on a
s ub s tant ia l num be r o f s mall entit ies un de r th e c ri t e ria of th e R eg ulat o r y F lex ibi li ty Ac t.
5

### List of Subjects in 14 CFR Part 39 A ir tran sportation , A ircraft, i\ 

### viatio n safe ty , In corpo ration by r efe rence , Safe ty. 

### The Proposed Ame ndment According ly, und er the autho ri ty d e legated to me by the Administrator, the FAA proposes to am e nd 14 CFR part 39 as follows: 

### PART 39- A IRWORTHINESS DIRE CT IVES I. The aut hority c i tation for part 39 cont inu es to r ead as fo ll ows: A uth ori t y: 49 U.S.C. 1 06(g) , 401 13 , 4470 

### I. 

### § 39.13 [Amended] 2. The FAA amends§ 39.13 by:
a. Removing airworth i ness directives (AD) 200 1-18-06 ; Ame ndment 39-12432 (66 FR47575 , Septe mber 13 , 200 1); and AD 2008-22- 1 6, Amendment 39-15712 (73 FR 63629, Octob e r 27 , 2008), and b. Adding the following new AD: 

### Ge n eral Electri c Co mpan y: Dock et No
. F AA-2008-0808; Directorate Ident ifier 2008- NE

- 18-AD. 

### (a) Com m e nts Due Date T he FAA mu s t receive comm e nts on thi s AD acti o n by [ I NSERT DATE 60 DAYS AFTER DATE OF PUBLlCA TION IN THE FEDERAL REGISTER]. 

### (b) Affected ADs T hi s AD replace s AD 2001-18-06 , Amen dment 39-12432 (66 F R 47575, Septe mb e r 13, 200 I ) and A D 2008-22-16, Amendment 39-157 1 2 (73 FR 63629, October 27,2008. 

### (c) Applicability This AD applie s to all General Elec tri c Company (GE) CT58-I 00 -2 , CT58-1l 0-l , CT58- 1 10-2 , CT58- 140-1 , and CT58-140-2 turboshaft eng in es. 

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### (d) U nsa f e Co ndition Thi s AD was prompted by r eca l culati o n of li fe for part s in s ta ll ed o n engines u sed in Uti li ty operat io n s, and a reduced lif e for comp r esso r s pool s in a ll ope rations. We are i ss uin g thi s AD to prevent failure of li fe- limi ted rotating part s , unc o nt a in e d part release , damage to the eng ine , a nd damage to th e a irc raft. (e) 

### Compliance Do the actio n s required by thi s AD, unl ess al ready don e . 

### (1) Calcu latin g Cy clic Life Consumptio n Re-calcul a t e th e cycles

- s in ce- n ew for a ll compressor s poo l s , a nd for l ife

- l imi ted
rotati n g part s o th e r than co mpress or spoo l s used in Utility operations. Use p a ragraph s 3.A.( l ) and 3 .8. ( 1 ) in the Acco m plishmen t In s tructions ofGE Ale r t Se rvice B ull etin (ASB) No. CT58 

### SIB 72-A0 1 62 , R evision 1 6 , d a t ed J anuary 7 , 20 1 5, to p e rform th e
ca lcu lations. (2) 

### Remov a l of Co mpre sso r Spoo l s After the e ff ec t ive date of th i s AD , r e m ove co mp resso r s p oo l s, part number s ( PINs) 5 124 T 94G02 , 6010T57G04 , 60 1 0T57G07 , an d 6010T57G08 from serv ice, b e fore reaching th e li fe limit s spec ified in paragraph 4.( 1}, A ppendi x A , in GE ASB No. CT58 

### SIB 72-AO 1 62, R ev i s ion 16 , dated Janu ary 7 , 20 I 5 , as r e-ca lculat e d p e r para g raph (e)( 

### I ) in thi s AD. (3) 

### Removal of Rotating Parts u se d in Utility Op era tions other than Co mpre sso r Spools Afte r th e ef f ecti ve date of thi s AD , r e m ove fro m se rv ice a n y life-limited rota tin g part u se d in U til ity operation s oth er th a n th e co mpressor s p ools w ith P INs listed in paragraph (e)(2) of this AD th a t exceed s it s lif e limit , as r e-calc ul ated per paragraph (e)( l) in thi s AD. Use Tab l es I , II , III , and IV in paragraph s 3.D. thro u g h 

### 3

. 0. in the Accomplis hm e nt In struc ti ons in GE ASB No. CT5 8 

### S I B 72-AO 16 2 , R ev i s ion 16 , dated

7January 7 , 2015, a nd paragrap h 4.(4) , A pp endix A , of th is GE ASB, to dete rmi ne w he n to
re m ove these p a rt s . 

### (4) Remova l of Rotating Parts not u s ed in Utility Operations other than Compressor Spoo l s After the effec ti ve date of thi s A D , re m ove from service any lif e- limited r otat in g pa r t not u sed i n Ut i l i ty o p erations other th a n the co mpre sso r spoo ls w ith PINs li sted in paragraph (e)(2) of thi s A D that excee d s it s li fe limits. Use Ta bl es 

### I , II , Ill , a nd IV in p a ra g raph s 3. D. thr o u g h 3.G. in th e Accomp li s hm ent Instruction s in G E AS B No. CT58 S/8 7 2

- A0 16 2, Revi s io n 1 6, dated J a nu ary 7 , 20 1 5 , and pa ra g r aph 4.(3) , Ap p e ndi x A of thi s GE ASB t o d e termi ne when to remove th ese p arts. 

### (f) A l ternativ e Method s of Compliance (AMOCs) Th e Manage r, E ngine Ce rtification Office , FAA, m ay approv e AMOCs for thi s A D. Use th e proce dures found in 14 CF R 39. 1 9 to make yo ur r e qu es t. You may emai l yo ur reque s t to: ANE-A D- AM O C @ faa.gov. (g) 

### Re l ate d Inform a tion ( 1) Fo r m ore infom 1 ation abo ut thi s A D , con tact Sanj a na Murth y, Aeros p ace E ngineer, E ng in e Cer ti fication Offic e, FAA , E ngi ne & Prope ll e r Dir ec t o rate , 12 New Eng land Exec u ti ve Pa rk, Burlin gto n , M A 0 1 803 ; phone: 781 -238-7 750 ; fax: 781 -23 8- 7 1 99; ema il : sa njana.murthy @ faa.gov. (2) GE ASB No. CT58 S/ B 72-A0162 , Rev ision 16 , dated J a nu ar y 7 , 2015, w h ich is not incorp orate d b y ref e r

e nce in th is p ropose d AD, can be obtai ne d from G E using the
co ntact inf ormation in p a ra g raph (g)(3) of thi s proposed AD

. (3) Fo r s erv ice inform ation id e ntifi ed in this AD , contact Gen e ra l E lectric Co mpan y, G E Aviation , Room 285, On e Ne um a nn Way , Cinc inn ati , OH 452 1 5; p hon e: 513-552

- 32 7 2; e mail: av iati on. tl eets upp o rt @ ge.com .



### 8(4) You may v iew this se r vice inform a ti on a t the FAA , E n g in e & Prope ll er Directorate, 12 New E ngland Exec uti ve Park , B urlinf,rton , MA. For inform ation on th e ava il abi I ity of this m ate rial at the FAA, call 78 1 -238-7 1 25.

Issued in Burl in gton, Massachusetts, o n April 17 , 20 1 5.



# Thom **asA ~**  Acting Man age r , En g i ne & Prop e ll e r Directorate, Aircraft Certificati o n Service.



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