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Rules and Regulations Federal Register

52213 

Vol. 76, No. 162 

Monday, August 22, 2011 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2010–0998; Directorate 

Identifier 2010–NE–29–AD; Amendment 39– 

16783; AD 2011–18–01] 

RIN 2120–AA64 

Airworthiness Directives; General 

Electric Company (GE) CF6–45 Series 

and CF6–50 Series Turbofan Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for the 

products listed above. This AD requires 

performing a fluorescent penetrant 

inspection (FPI) of the low-pressure 

turbine (LPT) rotor stage 3 disk at every 

shop visit at which the LPT module is 

separated from the engine. This AD was 

prompted by seven reports of 

uncontained failures of LPT rotor stage 

3 disks and eight reports of cracked LPT 

rotor stage 3 disks found during shop 

visit inspections. We are issuing this AD 

to prevent LPT rotor separation, which 

could result in an uncontained engine 

failure and damage to the airplane. 

DATES: This AD is effective September 

26, 2011. 

ADDRESSES: You may examine the AD 

docket on the Internet at http:// 

www.regulations.gov; or in person at the 

Docket Management Facility between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. The AD 

docket contains this AD, the regulatory 

evaluation, any comments received, and 

other information. The address for the 

Docket Office (phone: 800–647–5527) is 

Document Management Facility, U.S. 

Department of Transportation, Docket 

Operations, M–30, West Building 

Ground Floor, Room W12–140, 1200 

New Jersey Avenue, SE., Washington, 

DC 20590. 

FOR FURTHER INFORMATION CONTACT: 

Tomasz Rakowski, Aerospace Engineer, 

Engine Certification Office, FAA, Engine 

& Propeller Directorate, 12 New England 

Executive Park, Burlington, MA 01803; 

phone: (781) 238–7735; fax: (781) 238– 

7199; e-mail: tomasz.rakowski@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an airworthiness 

directive (AD) that would apply to the 

specified products. That NPRM 

published in the Federal Register on 

October 20, 2010, (75 FR 64681). That 

NPRM proposed to require performing a 

fluorescent penetrant inspection at 

every shop visit when the LPT module 

assembly is separated from the engine. 

Comments 

We gave the public the opportunity to 

participate in developing this AD. The 

following presents the comments 

received on the proposal and the FAA’s 

response to each comment. 

Support for the NPRM as Written 

Two commenters, the National 

Transportation Safety Board and The 

Boeing Company support the NPRM as 

written. 

Request To Define LPT Module 

Two commenters, GE and MTU 

Maintenance Canada, asked us to define 

‘‘LPT module.’’ The commenters feel the 

term LPT module could be confused 

with the LPT rotor assembly. 

We agree. We changed paragraph (e) 

of the proposed AD to clarify that the 

intent of this AD is to inspect the LPT 

rotor stage 3 disk when the LPT module 

assembly separates from the engine for 

maintenance, and added new 

paragraphs (i) and (i)(1) that define the 

LPT module assembly. 

Request To Require Only Conditional 

Inspection 

One commenter, MTU Maintenance 

Canada, asked us to change the 

compliance time for the inspection. 

MTU stated the proposed AD requires 

stage 3 disk FPI at piece-part level 

regardless of the part utilization (cyclessince-last inspection) or operational 

history since the last inspection. MTU 

asked us to change the inspection to the 

next time the LPT module assembly is 

disassembled to piece-part level for 

certain engine conditions only. 

We don’t agree with the request for 

conditional inspections only. The intent 

of this AD is to require an FPI of the LPT 

rotor stage 3 disk forward spacer arm at 

each shop visit where the LPT module 

assembly is separated in a cyclic 

manner, regardless of the reason for the 

separation. The requirements for 

conditional piece-part FPI are already 

mandated by AD 2011–02–07. We didn’t 

change the AD. 

Request To Add Conditional Inspection 

One commenter, Evergreen 

International Airlines, asked us to 

additionally require the inspection if the 

engine encountered excessive core 

vibration, or HPT blade separation or 

excessive material loss, or unserviceable 

LPT blade interlock wear, in addition to 

the repetitive inspections proposed in 

the NPRM. 

We don’t agree. The requirements for 

conditional piece-part FPI are already 

mandated by AD 2011–02–07. We didn’t 

change the AD. 

Request To Change the Compliance 

Time for the Inspection 

One commenter, Evergreen 

International Airlines, asked us to 

require inspections if the LPT rotor 

stage 3 disk hasn’t been FPI inspected 

within the last 2,000 cycles or at all. 

Evergreen stated the separation of the 

LPT module is required when the 

maintenance of certain HPC, combustor, 

and HPT assemblies and parts need to 

be performed. Engines removed for 

maintenance of those components 

would require LPT rotor stage 3 disk 

cleaning and FPI regardless of the time 

interval since the last FPI per the 

proposed AD, which would be an 

unnecessary burden on the operators. 

We partially agree. We agree with the 

request for a certain number of cycles 

since the last FPI to exclude the part 

from mandatory inspection. However, 

we do not find the number of 2,000 

cycles since last inspection (CSLI) 

appropriate to ensure a desired level of 

safety. We find that an acceptable level 

of safety will be retained when the disk 

FPI inspection is skipped during the 

shop visit if the disk was inspected 

within the last 1,000 cycles. We 

changed paragraphs (f) and (g) to ‘‘(f) At 

the next shop visit after the effective 

date of this AD, clean and fluorescent 

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52214 Federal Register / Vol. 76, No. 162 / Monday, August 22, 2011 / Rules and Regulations 

penetrant inspect the LPT rotor stage 3 

disk forward spacer arm, including the 

use of a wet abrasive blast to eliminate 

residual or background fluorescence 

before inspecting. You can find 

guidance on cleaning the disk and 

performing the FPI in the CF6–50 

Engine Manual, GEK 50481 72–57–02.’’ 

and ‘‘(g) Thereafter, clean and inspect 

the LPT rotor stage 3 disk forward 

spacer arm, as specified in paragraph (f), 

at each engine shop visit that occurs 

after 1,000 cycles since the last FPI of 

the LPT rotor stage 3 disk forward 

spacer arm.’’ We also added paragraphs 

(i) and (i)(2) that define an engine shop 

visit as follows: ‘‘An engine shop visit 

is the induction of an engine into the 

shop for maintenance involving the 

separation of the turbine mid-frame 

forward flange from the compressor rear 

frame aft flange, except that the 

separation of these engine flanges solely 

for the purposes of transportation 

without subsequent engine maintenance 

does not constitute an engine shop 

visit.’’ 

Request To Change the Type of 

Inspection 

One commenter, GE, asked us to 

consider changing the type of inspection 

from FPI to ultrasonic inspection (USI). 

GE stated that they have developed a 

USI technique and tooling which allow 

inspecting the LPT rotor stage 3 disk 

forward spacer arm without piece part 

disassembly of the LPT. Implementing 

the USI will detect cracks in the forward 

spacer arm, which might propagate 

during operation and would be a 

suitable alternative to the piece-part 

disassembly, cleaning, and FPI of the 

forward spacer arm in many situations. 

We don’t agree. We don’t believe USI 

technique specified in GE SB CF6–50 S/ 

B 72–1309 is a sufficient means of 

detecting flaws or microcracks on the 

inner surface of the LPT rotor stage 3 

disk forward spacer arm. Paragraph E.(5) 

of SB CF6–50 S/B 72–1309 states ‘‘The 

new USI probe was specifically 

designed to detect flaws 0.030 inch 

(0.76 mm) deep or greater in the forward 

spacer arm of the stage 3 LPTR disk.’’ 

We find that a 0.030-inch deep surface 

crack size is unacceptable in that 

location, as it would have already 

propagated in a high-cycle fatigue mode. 

The intent of this AD is to detect cracks 

before they propagate. We made no 

change to the proposed AD. 

Request To Change the Costs of 

Compliance 

Two commenters, MTU Canada and 

FedEx, asked us to re-evaluate the Costs 

of Compliance for the actions required 

by the proposed AD. The commenters 

state that cleaning the stage 3 disk and 

performing an FPI are done at the piecepart level, and that the costs of 

disassembling and reassembling the LPT 

module assembly, and of the 

inspections required by the engine 

manual for reinstalling the stage 3 

blades must be added to the cost of 

cleaning and inspecting the disk. 

We don’t agree. Our estimated cost is 

the direct cost to comply with the AD, 

and doesn’t include preparatory 

disassembly or reinstallation. We didn’t 

change the AD. 

Request To Change Paragraph (f) of the 

Proposed AD 

One commenter, GE, asked us to 

change paragraph (f) of the proposed AD 

to use the words ‘‘including the use of’’ 

in place of the word ‘‘using’’, where 

cleaning the LPT rotor stage 3 disk with 

wet-abrasive blast to eliminate residual 

or background fluorescence is required. 

GE doesn’t consider a wet-abrasive blast 

alone sufficient to clean the LPT rotor 

stage 3 disk to allow performance of the 

FPI of the inner diameter of the forward 

cone body of the LPT rotor stage 3 disk. 

We agree. We changed paragraph (f) of 

the proposed AD from ‘‘Clean the LPT 

rotor stage 3 disk, using a wet abrasive 

blast to eliminate residual or 

background fluorescence. You can find 

guidance on cleaning the disk in the 

cleaning procedure of CF6–50 Engine 

Manual, GEK 50481 72–57–02.’’ to ‘‘At 

the next engine shop visit after the 

effective date of this AD, clean and 

fluorescent-penetrant inspect the LPT 

rotor stage 3 disk forward spacer arm, 

including the use of a wet-abrasive blast 

to eliminate residual or background 

fluorescence before inspecting. You can 

find guidance on cleaning the disk and 

performing the FPI in the CF6–50 

Engine Manual, GEK 50481 72–57–02.’’ 

Request To Include Definitions for 

Cleaning and FPI of the LPT Rotor 

Stage 3 Disk 

One commenter, Evergreen 

International Airlines, asked us to add 

definitions of ‘‘cleaning the LPT rotor 

stage 3 disk’’ and ‘‘FPI of the LPT rotor 

stage 3 disk,’’ with specific engine 

manual subtask references, to the 

proposed AD. The commenter states 

that the definitions will clarify the 

actions required by the proposed AD. 

We don’t agree. The reference 

provided in the proposed AD is 

sufficient to define the required actions. 

We made no changes to the proposed 

AD. 

Conclusion 

We reviewed the relevant data, 

considered the comments received, and 

determined that air safety and the 

public interest require adopting the AD 

with the changes described previously. 

We also determined that these 

changes will not increase the economic 

burden on any operator or increase the 

scope of the AD. 

Costs of Compliance 

We estimate that this AD will affect 

387 engines installed on airplanes of 

U.S. registry. We also estimate that it 

will take about 7 work-hours per engine 

to clean and FPI the disk 387 engines. 

The average labor rate is $85 per workhour. No parts will be required. Based 

on these figures, we estimate the total 

cost of the AD to U.S. operators to be 

$230,265. 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. Subtitle VII: 

Aviation Programs, describes in more 

detail the scope of the Agency’s 

authority. 

We are issuing this rulemaking under 

the authority described in Subtitle VII, 

Part A, Subpart III, Section 44701: 

‘‘General requirements.’’ Under that 

section, Congress charges the FAA with 

promoting safe flight of civil aircraft in 

air commerce by prescribing regulations 

for practices, methods, and procedures 

the Administrator finds necessary for 

safety in air commerce. This regulation 

is within the scope of that authority 

because it addresses an unsafe condition 

that is likely to exist or develop on 

products identified in this rulemaking 

action. 

Regulatory Findings 

This AD will not have federalism 

implications under Executive Order 

13132. This AD will not have a 

substantial direct effect on the States, on 

the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify that this AD: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Is not a ‘‘significant rule’’ under 

DOT Regulatory Policies and Procedures 

(44 FR 11034, February 26, 1979), 

(3) Will not affect intrastate aviation 

in Alaska, and 

(4) Will not have a significant 

economic impact, positive or negative, 

on a substantial number of small entities 

under the criteria of the Regulatory 

Flexibility Act. 

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Federal Register / Vol. 76, No. 162 / Monday, August 22, 2011 / Rules and Regulations 52215 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

Adoption of the Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA amends 14 CFR part 39 as 

follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive (AD): 

2011–18–01 General Electric Company: 

Amendment 39–16783; Docket No. 

FAA–2010–0998; Directorate Identifier 

2010–NE–29–AD. 

Effective Date 

(a) This AD is effective September 26, 

2011. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to General Electric 

Company (GE) CF6–45A, CF6–45A2, CF6– 

50A, CF6–50C, CF6–50CA, CF6–50C1, CF6– 

50C2, CF6–50C2B, CF6–50C2D, CF6–50E, 

CF6–50E1, and CF6–50E2 series turbofan 

engines, including engines marked on the 

engine data plate as CF6–50C2–F and CF6– 

50C2–R, with a low-pressure turbine (LPT) 

rotor stage 3 disk that has a part number (P/ 

N) listed in Table 1 of this AD installed. 

TABLE 1—LPT ROTOR STAGE 3 DISK P/NS

1473M90P01 1473M90P02 1473M90P03 1473M90P04 

1479M75P01 1479M75P02 1479M75P03 1479M75P04 

1479M75P05 1479M75P06 1479M75P07 1479M75P08 

1479M75P09 1479M75P11 1479M75P13 1479M75P14 

9061M23P06 9061M23P07 9061M23P08 9061M23P09 

9061M23P10 9061M23P12 9061M23P14 9061M23P15 

9061M23P16 9224M75P01 

Unsafe Condition 

(d) This AD results from seven reports of 

uncontained failures of LPT rotor stage 3 

disks and eight reports of cracked LPT rotor 

stage 3 disks found during shop visit 

inspections. We are issuing this AD to 

prevent LPT rotor separation, which could 

result in an uncontained engine failure and 

damage to the airplane. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed at 

each shop visit after the effective date of this 

AD, at which the LPT module assembly is 

separated from the engine. 

Initial Inspection 

(f) At the next shop visit after the effective 

date of this AD, clean and fluorescentpenetrant inspect the LPT rotor stage 3 disk 

forward spacer arm, including the use of a 

wet-abrasive blast to eliminate residual or 

background fluorescence before inspecting. 

You can find guidance on cleaning the disk 

and performing the FPI in the CF6–50 Engine 

Manual, GEK 50481 72–57–02. 

Repetitive Inspection 

(g) Thereafter, clean and inspect the LPT 

rotor stage 3 disk forward spacer arm, as 

specified in paragraph (f) of this AD, at each 

engine shop visit that occurs after 1,000 

cycles since the last FPI of the LPT rotor 

stage 3 disk forward spacer arm. 

(h) If a crack or a band of fluorescence is 

present, remove the disk from service. 

Definitions 

(i) For the purpose of this AD: 

(1) The LPT module assembly is defined as 

consisting of turbine mid-frame, LPT stage 1 

nozzle, LPT stator cases and vanes, LPT 

rotor, and turbine rear frame. 

(2) An engine shop visit is the induction 

of an engine into the shop for maintenance 

involving the separation of the turbine midframe forward flange from the compressor 

rear frame aft flange, except that the 

separation of these engine flanges solely for 

the purposes of transportation without 

subsequent engine maintenance does not 

constitute an engine shop visit. 

Alternative Methods of Compliance 

(j) The Manager, Engine Certification 

Office, has the authority to approve 

alternative methods of compliance for this 

AD if requested using the procedures found 

in 14 CFR 39.19. 

Related Information 

(k) For more information about this AD, 

contact Tomasz Rakowski, Aerospace 

Engineer, Engine Certification Office, FAA, 

Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 

01803; phone: (781) 238–7735; fax: (781) 

238–7199; e-mail: tomasz.rakowski@faa.gov. 

Material Incorporated by Reference 

(l) None. 

Issued in Burlington, Massachusetts on 

August 15, 2011. 

Peter A. White, 

Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

[FR Doc. 2011–21312 Filed 8–19–11; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–0187; Directorate 

Identifier 2011–NE–07–AD; Amendment 39– 

16784; AD 2011–18–02] 

RIN 2120–AA64 

Airworthiness Directives; General 

Electric Company CF34–10E2A1; 

CF34–10E5; CF34–10E5A1; CF34– 

10E6; CF34–10E6A1; CF34–10E7; and 

CF34–10E7–B Turbofan Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for the 

products listed above with certain part 

number (P/N) fan rotor spinners 

installed. This AD requires removing 

from service certain fan rotor blade 

retainers, and removing from service the 

fan rotor spinner support that was 

installed with those fan rotor blade 

retainers. This AD was prompted by a 

fan rotor spinner support found cracked 

at the attachment lugs. We are issuing 

this AD to prevent high-cycle fatigue 

cracking of the fan rotor spinner support 

attachment lugs, leading to separation of 

the fan rotor spinner assembly, 

uncontained failure of the engine, and 

damage to the airplane. 

DATES: This AD is effective September 

26, 2011. 

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