[Federal Register Volume 86, Number 33 (Monday, February 22, 2021)]
[Proposed Rules]
[Pages 10496-10498]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-01814]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1179; Project Identifier AD-2020-00818-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 adopt a new airworthiness directive (AD) 
for all 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, CF6-80C2B1F1, CF6-80C2B1F2, CF6-
80C2B2, CF6-80C2B2F, CF6-80C2B3F, CF6-80C2B4, CF6-80C2B4F, CF6-80C2B5F, 
CF6-80C2B6, CF6-80C2B6F, CF6-80C2B6FA, CF6-80C2B7F, CF6-80C2B8F, CF6-
80C2D1F, CF6-80C2K1F and CF6-80C2L1F model turbofan engines. This 
proposed AD was prompted by an inspection by the manufacturer that 
revealed cracking of the high-pressure turbine (HPT) rotor stage 1 
disk. This proposed AD would require visual inspection and fluorescent 
penetrant inspection (FPI) of the HPT thermal shield and, if cracking 
is detected, removal from service of the HPT thermal shield, HPT rotor 
stage 1 disk and HPT rotor stage 2 disk. 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 April 8, 
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: [email protected]; website: www.ge.com. 
You may view this 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-1179; 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: Kevin M. Clark, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7088; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

[[Page 10497]]

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-2020-1179; Project Identifier 
AD-2020-00818-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 
this 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 received about this NPRM.

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 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 Kevin 
M. Clark, 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 was notified by the manufacturer that a crack on the HPT 
rotor stage 1 disk was found during an inspection. Subsequent 
investigation by the manufacturer determined that the crack on the HPT 
rotor stage 1 disk was caused by increased stress on the HPT rotor 
stage 1 disk as a result of flange-to-flange cracking on the HPT 
thermal shield. This condition, if not addressed, could result in 
failure of the HPT rotor stage 1 disk, failure of the HPT rotor stage 2 
disk, uncontained release of the HPT rotor stage 1 and stage 2 disks, 
damage to the engine, and damage to the airplane.

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

    The FAA reviewed ESM 72-53-00 High Pressure Turbine Rotor 
Assembly--Disassembly (ESM 72-53-00) from the GE CF6-80A Engine Manual 
GEK72501--Rev 89, dated February 15, 2020. ESM 72-53-00 describes 
procedures for the removal of the HPT thermal shield, the HPT rotor 
stage 1 disk, and the HPT rotor stage 2 disk.

Proposed AD Requirements in This NPRM

    This proposed AD would require repetitive visual inspection and FPI 
of the HPT thermal shield at every piece part opportunity of the HPT 
rotor stage 1 disk, HPT rotor stage 2 disk, or the HPT thermal shield. 
Depending on the results of the inspections, this proposed AD requires 
the removal from service of the HPT thermal shield, HPT rotor stage 1 
disk, and the HPT rotor stage 2 disk.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,084 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
----------------------------------------------------------------------------------------------------------------
Perform FPI and visual inspection of  2 work-hours x $85 per               $0             $170         $184,280
 HPT thermal shield.                   hour = $170.
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    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 HPT thermal shield....................  2 work-hours x $85 per hour =           $209,600        $209,770
                                                 $170.
Replace HPT rotor stage 1 disk................  2 work-hours x $85 per hour =            799,700         799,870
                                                 $170.
Replace HPT rotor stage 2 disk................  2 work-hours x $85 per hour =            364,600         364,770
                                                 $170.
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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

[[Page 10498]]

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

    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 this 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 adding the following new airworthiness 
directive:

General Electric Company: Docket No. FAA-2020-1179; Project 
Identifier AD-2020-00818-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by April 8, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all 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-
80C2B1F1, CF6-80C2B1F2, CF6-80C2B2, CF6-80C2B2F, CF6-80C2B3F, CF6-
80C2B4, CF6-80C2B4F, CF6-80C2B5F, CF6-80C2B6, CF6-80C2B6F, CF6-
80C2B6FA, CF6-80C2B7F, CF6-80C2B8F, CF6-80C2D1F, CF6-80C2K1F and 
CF6-80C2L1F model turbofan engines.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by an inspection by the manufacturer that 
revealed cracking of the high-pressure turbine (HPT) rotor stage 1 
disk, caused by initial flange-to-flange cracking on the HPT thermal 
shield between the HPT rotor stage 1 disk and the HPT rotor stage 2 
disk. The FAA is issuing this AD to prevent failure of the HPT rotor 
stage 1 disk and the HPT rotor stage 2 disk. The unsafe condition, 
if not addressed, could result in uncontained release of the HPT 
rotor stage 1 and stage 2 disks, 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, at every piece-part 
exposure of the HPT rotor stage 1 disk, HPT rotor stage 2 disk, or 
the HPT thermal shield, perform a visual inspection and a 
fluorescent penetrant inspection (FPI) of the HPT thermal shield.
    (2) During any inspection required by paragraph (g)(1) of this 
AD, if a crack extending through either the forward or aft flange of 
the HPT thermal shield is detected, remove the HPT thermal shield, 
the HPT rotor stage 1 disk, and the HPT rotor stage 2 disk from 
service.

(h) Installation Prohibition

    Do not install onto any engine an HPT rotor stage 1 disk or HPT 
rotor stage 2 disk that was removed from service due to the 
requirements of paragraph (g)(2) of this AD.

(i) Definition

    For the purpose of this AD, ``piece-part exposure'' is when the 
HPT rotor stage 1 disk, HPT rotor stage 2 disk, or HPT thermal 
shield is separated from their mating rotor parts within the HPT 
rotor module.

(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 
ECO Branch, send it to the attention of the person identified in 
Related Information. You may email your request to: [email protected].
    (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 Kevin M. Clark, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7088; fax: (781) 238-7199; 
email: [email protected].
    (2) For service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: [email protected]; 
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 January 20, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-01814 Filed 2-19-21; 8:45 am]
BILLING CODE 4910-13-P