[Federal Register Volume 86, Number 139 (Friday, July 23, 2021)]
[Rules and Regulations]
[Pages 38912-38914]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15694]


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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; 
Amendment 39-21638; AD 2021-14-11]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) CF6-80A and CF6-80C2 model 
turbofan engines. This AD was prompted by an inspection by the 
manufacturer that revealed cracking of the high-pressure turbine (HPT) 
rotor stage 1 disk. This AD requires 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 issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective August 27, 2021.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: <a href="/cdn-cgi/l/email-protection#f392859a92879a9c9ddd959f969687808683839c8187b39296dd9496dd909c9e"><span class="__cf_email__" data-cfemail="610017080015080e0f4f070d040415121411110e13152100044f06044f020e0c">[email protected]</span></a>; 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. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-1179.

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 final rule, any 
comments received, and other information. The address for Docket 
Operations is 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: Kevin M. Clark, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7088; fax: (781) 238-7199; email: 
<a href="/cdn-cgi/l/email-protection#155e70637c7b3b583b567974677e557374743b727a63"><span class="__cf_email__" data-cfemail="eda6889b8483c3a0c3ae818c9f86ad8b8c8cc38a829b">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply 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. The NPRM published in the Federal 
Register on February 22, 2021 (86 FR 10496). The NPRM was prompted by 
an inspection by the manufacturer that revealed cracking of the HPT 
rotor stage 1 disk caused by increased stress on the HPT rotor stage 1 
disk as a result of flange-to-flange cracking on the HPT thermal 
shield. In the NPRM, the FAA proposed to require visual inspection and 
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 issuing this AD to address the unsafe 
condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from five commenters. The commenters were 
Atlas Air, Boeing Commercial Airplanes (Boeing), Delta Air Lines 
(Delta), United Airlines (United) and the Air Line Pilots Association, 
International (ALPA). The following presents the comments received on 
the NPRM and the FAA's response to each comment.

Request To Update Shop Manual

    Atlas Air requested that the FAA revise GE CF6-80C2, ESM 72-53-05, 
High Pressure Turbine (HPT) Rotor Thermal Shield--Inspection to add the 
proposed requirement to remove from service the HPT thermal shield, the 
HPT rotor stage 1 disk, and the HPT rotor stage 2 disk from service if 
a crack is found, since the thermal shield can be sent to different 
vendors outside the engine shop. Delta also suggested that the 
technical data within the Engine Shop Manual (ESM) should be updated to 
ensure inspection requirements are equivalent across all tasks within 
the ESM.
    The FAA disagrees. Requiring updates to the ESM is unnecessary to 
correct the unsafe condition identified in this AD. The visual and FPI 
inspections in the required actions of this AD are the necessary 
actions to correct the unsafe condition. Operators, at their 
discretion, may work with the original equipment manufacturer to 
suggest changes to the ESM to include the inspections required by this 
AD.

[[Page 38913]]

Request To Revise References to Engine Manual

    Boeing requested that the FAA update reference to the service 
information in the Related Service Information section of the NPRM by 
referencing Revision 90 of the GE CF6-80A Engine Manual and Revision 91 
of the CF6-80C2 Engine Manual. These revisions of the respective 
engines manuals include updated procedures regarding HPT rotor Stage 1 
and Stage 2 disk serviceability for these model engines with respect to 
HPT thermal shield inspection findings.
    The FAA agrees and has updated the Related Service Information 
section of this AD as suggested by the commenter.

Request To Clarify Inspection Instructions

    Delta requested that the FAA clarify that the mandated visual and 
FPI inspections should be accomplished in accordance with the engine 
manual for the affected engine models.
    The FAA disagrees. Operators may use any approved method to perform 
the visual and FPI inspections required by this AD.

Request To Clarify Engine Applicability

    United requested that the FAA remove CF6-80C2B8F model turbofan 
engines from the applicability of this AD. United commented that two 
HPT thermal shield configurations exist, part number (P/N) 2787M85P01 
and P/N 9315M41P20. Neither of these configurations are applicable to 
the R88DT HPT rotor installed on CF6-80C2B8F model turbofan engines. 
United requested that if the FAA considers the CF6-80C2B8F turbofan 
engine model affected by this AD, then the applicable engine manual 
should be updated to reflect the inspections required by this AD.
    The FAA agrees. This AD is not applicable to the R88DT HPT rotor 
installed on CF6-80C2B8F model turbofan engines because that rotor 
configuration does not have an affected thermal shield. The FAA added 
the applicable part numbers for HPT thermal shields installed on CF6-
80A and CF6-80C2 model turbofan engines to the applicability paragraph 
of this AD.

Support for the NPRM

    ALPA supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes and any 
other changes described previously, this AD is adopted as proposed in 
the NPRM. None of the changes will increase the economic burden on any 
operator.

Related Service Information

    The FAA reviewed ESM 72-53-00 High Pressure Turbine Rotor 
Assembly--Disassembly (CF6-80A ESM 72-53-00), dated February 15, 2020 
from the GE CF6-80A Engine Manual GEK72501--Rev 90, dated February 15, 
2021. CF6-80A 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 installed on CF6-80A model turbofan engines.
    The FAA also reviewed ESM 72-53-00 High Pressure Turbine Rotor 
Assembly--Disassembly (CF6-80C2 ESM 72-53-00), dated December 1, 2019 
from the GE CF6-80C2 Engine Manual GEK92451--Rev 91, dated December 1, 
2020. CF6-80C2 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 installed on CF6-80C2 model turbofan engines.

Costs of Compliance

    The FAA estimates that this AD affects 1,084 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this 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.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
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.
----------------------------------------------------------------------------------------------------------------

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 38914]]

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) Will not affect intrastate aviation in Alaska, and
    (3) 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.

List of Subjects in 14 CFR Part 39

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

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

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:

2021-14-11 General Electric Company: Amendment 39-21638; Docket No. 
FAA-2020-1179; Project Identifier AD-2020-00818-E.

(a) Effective Date

    This airworthiness directive (AD) is effective August 27, 2021.

(b) Affected ADs

    None.

(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-
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 with an installed thermal shield 
having one of the following part numbers: 2787M85P01, 9315M41P09, 
9315M41P13, 9315M41P14, 9315M41P15, 9315M41P16, 9315M41P20, 
9348M13P01, 9367M63P01, 9367M63P02, 9367M63P03, 9367M63P04, 
9367M63P05, 9367M63P06, 9367M63P07, or 9315M41P20.

(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 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: <a href="/cdn-cgi/l/email-protection#1958575c34585d345854565a597f7878377e766f"><span class="__cf_email__" data-cfemail="f7b6b9b2dab6b3dab6bab8b4b7919696d9909881">[email protected]</span></a>.
    (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

    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: <a href="/cdn-cgi/l/email-protection#074c62716e69294a29446b66756c4761666629606871"><span class="__cf_email__" data-cfemail="6b200e1d020545264528070a19002b0d0a0a450c041d">[email protected]</span></a>.

(l) Material Incorporated by Reference

    None.

    Issued on June 25, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-15694 Filed 7-22-21; 8:45 am]
BILLING CODE 4910-13-P


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