Document ID: FAA-2021-0791-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2021-10-06T04:00Z

[Federal Register Volume 86, Number 191 (Wednesday, October 6, 2021)]
[Proposed Rules]
[Pages 55545-55547]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-21643]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0791; Project Identifier AD-2021-00716-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2020-20-13, which applies to certain General Electric Company (GE) CF6-
80A and CF6-80C model turbofan engines. AD 2020-20-13 requires 
ultrasonic inspection (UI) of high-pressure turbine (HPT) stage 1 and 
stage 2 disks and replacement of any HPT stage 1 or stage 2 disk that 
fails the inspection. Since the FAA issued AD 2020-20-13, the 
manufacturer determined that the requirement to perform UI of affected 
HPT stage 1 and stage 2 disks should be expanded to include an 
additional population of affected HPT stage 1 and stage 2 disks. This 
proposed AD would retain the required UI while expanding the population 
of affected HPT stage 1 and stage 2 disks. The FAA is proposing this AD 
to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by November 
22, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact General 
Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 
552-3272; email: aviation.fleetsupport@ae.ge.com; website: www.ge.com. 
You may view this service information at the Airworthiness Products 
Section, Operational Safety Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
material at the FAA, call (781) 238-7759.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0791; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Sungmo Cho, Aviation Safety Engineer, 
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 
(781) 238-7241; fax: (781) 238-7199; email: Sungmo.D.Cho@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0791; Project Identifier 
AD-2021-00716-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
the proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact we receive about this proposed AD.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each

[[Page 55546]]

page of your submission containing CBI as ``PROPIN.'' The FAA will 
treat such marked submissions as confidential under the FOIA, and they 
will not be placed in the public docket of this NPRM. Submissions 
containing CBI should be sent to Sungmo Cho, Aviation Safety Engineer, 
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803. Any 
commentary that the FAA receives which is not specifically designated 
as CBI will be placed in the public docket for this rulemaking.

Background

    The FAA issued AD 2020-20-13, Amendment 39-21269 (85 FR 63193, 
October 7, 2020), (AD 2020-20-13), for certain GE CF6-80A, CF6-80A1, 
CF6-80A2, CF6-80A3, CF6-80C2A1, CF6-80C2A2, CF6-80C2A3, CF6-80C2A5, 
CF6-80C2A5F, CF6-80C2A8, CF6-80C2B1, CF6-80C2B1F, CF6-80C2B2, CF6-
80C2B2F, CF6-80C2B4, CF6-80C2B4F, CF6-80C2B5F, CF6-80C2B6, CF6-80C2B6F, 
CF6-80C2B6FA, CF6-80C2B7F, CF6-80C2D1F, CF6-80C2L1F, and CF6-80C2K1F 
model turbofan engines. AD 2020-20-13 was prompted by an uncontained 
failure of an HPT stage 2 disk and the manufacturer's determination to 
expand the population of affected HPT disks. AD 2020-20-13 retains the 
required inspections of AD 2018-15-04 (83 FR 43739; August 28, 2018), 
while expanding the population of affected HPT disks. The agency issued 
AD 2020-20-13 to prevent failure of the HPT stage 1 disk (CF6-80C2 
engines) and the HPT stage 2 disk (CF6-80C2 and CF6-80A engines).

Actions Since AD 2020-20-13 Was Issued

    Since the FAA issued AD 2020-20-13, the manufacturer discovered an 
error in the service information and determined that the requirement to 
perform UI of affected HPT stage 1 and 2 disks should be expanded to 
include an additional population of HPT stage 1 and stage 2 disks. GE, 
therefore, revised its service information to include the additional 
affected HPT stage 1 and stage 2 disks.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE CF6-80C Service Bulletin (SB) 72-1562 R05, 
dated March 19, 2021 (GE SB 72-1562). The SB specifies procedures for 
UI of CF6-80C2 turbofan engine HPT stage 1 and 2 disks. The FAA also 
reviewed GE CF6-80A SB 72-0869 R03, dated March 19, 2021 (GE SB 72-
0869). This SB specifies procedures for UI of CF6-80A turbofan engine 
HPT stage 2 disks. This service information is reasonably available 
because the interested parties have access to it through their normal 
course of business or by the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would retain all the requirements of AD 2020-20-
13. This proposed AD would require UI of HPT stage 1 and stage 2 disks 
and replacement of any HPT stage 1 or stage 2 disk that fails the 
inspection. This proposed AD would also expand the applicability to 
include an additional population of affected HPT stage 1 and 2 disks.

Differences Between This Proposed AD and the Service Information

    GE SB 72-1562 and GE SB 72-0869 specify that information, including 
the disk part number, disk serial number, accumulated cycles to date, 
and documented results of the inspection must be sent to GE Aviation 
Fleet Support. This proposed AD would not mandate sending information 
to GE Aviation Fleet Support.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,512 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
UI of HPT stage 1 and stage 2 disks...  10 work-hours x $85 per               $0            $850      $1,285,200
                                         hour = $850.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
proposed inspection. The agency has no way of determining the number of 
aircraft that might need these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace CF6-80C2 HPT stage 1 disk.............  0.25 work-hours x $85 per hour =        $799,700     $799,721.25
                                                 $21.25.
Replace CF6-80C2 HPT stage 2 disk.............  0.25 work-hours x $85 per hour =         364,600      364,621.25
                                                 $21.25.
Replace CF6-80A HPT stage 2 disk..............  0.25 work-hours x $85 per hour =         344,000      344,021.25
                                                 $21.25.
----------------------------------------------------------------------------------------------------------------

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.
    The FAA is 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.

[[Page 55547]]

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

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

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive 2020-20-13, Amendment 39-21269 (85 
FR 63193, October 7, 2020); and
0
b. Adding the following new airworthiness directive:

General Electric Company: Docket No. FAA-2021-0791; Project 
Identifier AD-2021-00716-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by November 22, 2021.

(b) Affected ADs

    This AD replaces AD 2020-20-13, Amendment 39-21269 (85 FR 63193, 
October 7, 2020).

(c) Applicability

    This AD applies to General Electric Company (GE) CF6-80A, CF6-
80A1, CF6-80A2, CF6-80A3, CF6-80C2A1, CF6-80C2A2, CF6-80C2A3, CF6-
80C2A5, CF6-80C2A5F, CF6-80C2A8, CF6-80C2B1, CF6-80C2B1F, CF6-
80C2B2, CF6-80C2B2F, CF6-80C2B4, CF6-80C2B4F, CF6-80C2B5F, CF6-
80C2B6, CF6-80C2B6F, CF6-80C2B6FA, CF6-80C2B7F, CF6-80C2D1F, CF6-
80C2L1F, and CF6-80C2K1F model turbofan engines with high-pressure 
turbine (HPT) disks with serial numbers listed in Tables 1 and 2 of 
Appendix A, paragraph 4., in GE CF6-80C2 Service Bulletin (SB) 72-
1562 R05, dated March 19, 2021 (GE SB 72-1562), and Table 1 of 
Appendix--A, paragraph 4., in GE CF6-80A SB 72-0869 R03, dated March 
19, 2021 (GE SB 72-0869).

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by an uncontained failure of an HPT stage 2 
disk and the manufacturer's determination to expand the population 
of affected HPT disks. The FAA is issuing this AD to prevent failure 
of the HPT stage 1 disk (CF6-80C2 engines) and the HPT stage 2 disk 
(CF6-80C2 and CF6-80A engines). The unsafe condition, if not 
addressed, could result in an uncontained HPT disk release, damage 
to the engine, and damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) After the effective date of this AD, perform an ultrasonic 
inspection (UI) for cracks in HPT stage 1 and stage 2 disks on the 
CF6-80C2 turbofan engine at each piece-part exposure using the 
Accomplishment Instructions, paragraph 3.A.(2), of GE SB 72-1562.
    (2) After the effective date of this AD, perform a UI for cracks 
in HPT stage 2 disks on the CF6-80A turbofan engine at each piece-
part exposure using the Accomplishment Instructions, paragraph 
3.A.(2), of GE SB 72-0869.
    (3) If any disk fails the inspection required by paragraph 
(g)(1) or (2) of this AD, replace the disk with a part eligible for 
installation before further flight.

(h) No Reporting Requirements

    The reporting requirements specified in the Accomplishment 
Instructions, paragraphs 3.A.(2)(c) and 3.A.(2)(f), of GE SB 72-
1562, and paragraph 3.A.(3), of GE SB 72-0869, are not required by 
this AD.

(i) Definitions

    (1) For the purpose of this AD, a ``part eligible for 
installation'' is an HPT stage 1 or stage 2 disk:
    (i) That has been inspected in accordance with paragraph (g)(1) 
or (2) of this AD and a crack or rejectable indication was not 
found; or
    (ii) With a serial number not listed in Tables 1 and 2 of 
Appendix A, paragraph 4., in GE SB 72-1562, and Table 1 of 
Appendix--A, paragraph 4., in GE SB 72-0869.
    (2) For the purpose of this AD, ``piece-part exposure'' of the 
HPT stage 1 or stage 2 disk is the separation of that HPT disk from 
its mating rotor parts within the HPT rotor module (thermal shield 
and HPT stage 1 and stage 2 disk, respectively).

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO Branch, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. In accordance with 14 CFR 39.19, send your request to your 
principal inspector or local Flight Standards District Office, as 
appropriate. If sending information directly to the manager of the 
certification office, send it to the attention of the person 
identified in paragraph (k)(1) of this AD. Information may be 
emailed to: ANE-AD-AMOC@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Related Information

    (1) For more information about this AD, contact Sungmo Cho, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7241; fax: (781) 238-7199; 
email: Sungmo.D.Cho@faa.gov.
    (2) For service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: aviation.fleetsupport@ae.ge.com; 
website: www.ge.com. You may view this referenced service 
information at the FAA, Airworthiness Products Section, Operational 
Safety Branch, 1200 District Avenue, Burlington, MA 01803. For 
information on the availability of this material at the FAA, call 
(781) 238-7759.

    Issued on September 10, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-21643 Filed 10-5-21; 8:45 am]
BILLING CODE 4910-13-P