Document ID: FAA-2017-0792-0011
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2018-03-30T04:00Z

[Federal Register Volume 83, Number 62 (Friday, March 30, 2018)]
[Proposed Rules]
[Pages 13703-13706]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-06390]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0792; Product Identifier 2017-NE-28-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening 
of comment period.

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SUMMARY: We are revising an earlier proposal for certain 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 turbofan engines. 
This action revises the notice of proposed rulemaking (NPRM) by 
removing certain engine models and adding a new part number (P/N) to 
the applicability and by revising the references to the service 
information. We are proposing this airworthiness directive (AD) to 
address the unsafe condition on these products. Since these actions 
would impose an additional burden over those in the NPRM, we are 
reopening the comment period to allow the public the chance to comment 
on these changes.

DATES: The comment period for the NPRM published in the Federal

[[Page 13704]]

Register on September 7, 2017 (82 FR 42261) is reopened.
    We must receive comments on this SNPRM by May 14, 2018.

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 http://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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this SNPRM, contact General 
Electric Company, GE Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 
45215; phone: 513-552-3272; email: [email protected]. You 
may view this service information at the FAA, Engine and Propeller 
Standards Branch, 1200 District Avenue, Burlington, MA. 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 on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-
0792; 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 SNPRM, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations (phone: 800-647-
5527) is listed above. Comments will be available in the AD docket 
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Herman Mak, Aerospace Engineer, ECO 
Branch, FAA, 1200 District Ave., Burlington, MA 01803; phone: 781-238-
7147; fax: 781-238-7199; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2017-0792; 
Product Identifier 2017-NE-28-AD'' at the beginning of your comments. 
We specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this SNPRM. We will consider all 
comments received by the closing date and may amend this SNPRM because 
of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this SNPRM.

Discussion

    We issued an NPRM to amend 14 CFR part 39 by adding an AD that 
would apply to GE turbofan engines, models 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, CF6-80C2L1F, and CF6-80C2K1F with high-pressure turbine (HPT) 
disks with part numbers and serial numbers (S/Ns) listed in Table 1 and 
2 of Appendix A in GE Service Bulletin (SB) CF6-80C2 S/B 72-1562, 
Revision 01, dated July 28, 2017. The NPRM published in the Federal 
Register on September 7, 2017 (82 FR 42261). The NPRM was prompted by 
an uncontained failure of an HPT stage 2 disk that resulted in a fire. 
The NPRM proposed to require ultrasonic inspection (UI) of HPT stage 1 
and 2 disks.

Actions Since the NPRM Was Issued

    Since we issued the NPRM, we determined the need to remove certain 
engine models and to add a new part number to the applicability of this 
AD. We determined the need to revise references to the service 
information in this AD because, since the publication of the NPRM, GE 
published the list of affected HPT S/Ns in two separate SBs applicable 
to the CF6-80A and CF6-80C2 engines.

Comments

    We gave the public the opportunity to comment on the NPRM. The 
following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Change Definition

    MTU Maintenance Hannover, Lufthansa Technik AG, and GE requested 
modification of the definition of ``piece part exposure.'' They 
reasoned a modification of the definition would prevent unintended 
inspections on disks.
    We agree. Modification of the definition of ``piece part exposure'' 
will clarify the intent of when the inspections are to be accomplished. 
We changed the Definition paragraph in this AD to clarify that ``piece-
part exposure'' involves separation of the HPT disk from its mating 
rotor parts.

Request To Clarify the Unsafe Condition

    The Boeing Company (Boeing) and GE requested we add wording 
identifying the HPT stage 1 or HPT stage 2 disk, as appropriate, with 
the associated CF6-80A and CF6-80C2 engine models in the unsafe 
condition paragraph of this AD. These commenters requested the change 
to provide clarification and avoid confusion.
    We agree. We changed the Unsafe Condition paragraph in this AD as 
requested by the commenters.

Request To Remove Engines Models From Applicability

    Boeing and GE requested we modify the applicability of this AD by 
removing certain GE engine models. GE commented that the affected HPT 
disks are not certified for use in the GE CF6-80C2B8F engine model and, 
therefore, this model should be removed from the AD. Boeing commented 
that GE CF6-80C2B3F, CF6-80C2L1F and CF6-80C2K1F engine models are not 
part of the Boeing 767/747 type certificate data sheet (TCDS) and, 
therefore, these models should be removed from the AD.
    In addition, we learned from discussions with GE that GE CF6-
80C2B1F1 and CF6-80C2B1F2 engine models have never been produced and 
therefore should be removed from this AD.
    We partially agree. We disagree with removing GE CF6-80C2L1F and 
CF6-80C2K1F engine models from applicability. These models are present 
on the engine TCDS. Further, the applicable HPT disks are eligible for 
installation on GE engine models CF6-80C2L1F and CF6-80C2K1F and these 
engine models may be exposed to the applicable HPT disks during an 
engine overhaul.
    We agree with removing the GE CF6-80C2B1F1, CF6-80C2B1F2, CF6-
80C2B3F, and CF6-80C2B8F engine models from the applicability section 
of this AD because these engine models were never produced or the 
applicable HPT disks in this AD are not eligible for installation in 
these engine models. We

[[Page 13705]]

removed the GE CF6-80C2B1F1, CF6-80C2B1F2, CF6-80C2B3F, and CF6-80C2B8F 
engine models from this AD.

Revision to Part Numbers in Applicability

    GE further commented that it had added HPT Stage 1 disk P/N 
2047M32G06 to the Effectivity paragraph of the GE SB CF6-80C2 S/B 72-
1562. This is a field rework part number that is created from P/N 
1531M84G08 and the serial number is not changed by the re-work 
procedure. GE noted that operators could have re-worked one or more of 
affected HPT disks, P/N 1531M84G08, into HPT disks, P/N 2047M32G06. 
Therefore, GE added this P/N to the SB.
    We considered this comment and determined the need to add P/N 
2047M32G06 to the applicability of this AD. We are issuing this SNPRM 
to allow the public the opportunity to comment on this change.

Request To Change Service Information

    Boeing, Delta Air Lines, and GE requested inclusion of GE SB CF6-
80A SB 72-0869 R01, dated October 19, 2017, in the applicability 
section of this AD.
    We agree. Since the publication of the NPRM, GE has published the 
list of affected HPT S/Ns in two SBs applicable to the CF6-80A and CF6-
80C2 engine models. We are issuing this SNPRM to allow the public the 
opportunity to comment on this change.

Request To Change Service Information

    Delta Air Lines and GE requested an update to the latest revision 
of GE CF6-80C2 SB 72-1562.
    We agree. We revised the reference to GE CF6-80C2 SB 72-1562 to 
include Revision 3, dated January 10, 2018. We are issuing this SNPRM 
to allow the public the opportunity to comment on this change.

Request To Change Costs of Compliance

    FedEx Express requested revising the Costs of Compliance paragraph 
to provide a better estimate of costs associated with the HPT stage 1 
and 2 disk inspections as well as to account for repetitive 
inspections. FedEx Express commented that the ``Estimated Costs'' table 
in the NPRM indicates 10 work-hours to perform the UI of each HPT disk. 
FedEx Express commented that this calculation does not appear to 
consider an engine with both a Stage 1 and a Stage 2 HPT Disk affected 
by GE SB 72-1562. FedEx Express indicated that it has learned from GE 
that 10 work-hours is the expected inspection time per disk (either 
Stage 1 or Stage 2), not per engine. Therefore, an inspection of 
engines with two affected disks would require 20 work-hours per shop 
visit. Further, this cost estimate only takes into account the initial 
inspection and does not reflect that the proposed action is to be 
performed at every ``piece-part exposure.''
    We disagree. Our estimate in the NPRM was based on an estimated 
population of 640 installed disks. Therefore, our labor estimate of 10 
hours per disk and our total cost estimate remain accurate. We only 
account for initial inspections in our cost estimates. Repetitive 
inspection costs are not included. We, however, did change the Cost of 
Compliance section of this AD to provide better clarification.

Support for the NPRM

    The National Transportation Safety Board and Air Line Pilots 
Association supported the NPRM.

Related Service Information Under 1 CFR Part 51

    We reviewed GE CF6-80C2 SB 72-1562 R03, dated January 10, 2018. The 
SB describes procedures for UI of HPT stage 1 and 2 disks. We also 
reviewed GE CF6-80A SB 72-0869 R01, dated October 19, 2017. The SB 
describes procedures for UI of HPT stage 2 disks. This SB information 
is reasonably available because the interested parties have access to 
it through their normal course of business or by the means identified 
in the ADDRESSES section.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
Certain changes described above expand the scope of the NPRM. As a 
result, we have determined that it is necessary to reopen the comment 
period to provide additional opportunity for the public to comment on 
this SNPRM.

Proposed Requirements of This SNPRM

    This SNPRM would require accomplishing the actions specified in the 
service information described previously.

Costs of Compliance

    We estimate that this proposed AD affects 640 HPT disks on engines 
installed on airplanes of U.S. registry.
    We estimate 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 disk........................  10 work-hours x $85 per               $0            $850        $544,000
                                         hour = $850.
----------------------------------------------------------------------------------------------------------------

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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to engines, propellers, and 
associated appliances to the Manager, Engine and Propeller Standards 
Branch, Policy and Innovation Division.

[[Page 13706]]

Regulatory Findings

    We 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) Is not a ``significant rule'' under the 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.

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 (AD):

General Electric Company: Docket No. FAA-2017-0792; Product 
Identifier 2017-NE-28-AD.

(a) Comments Due Date

    We must receive comments by May 14, 2018.

(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-
80C2B2, CF6-80C2B2F, CF6-80C2B4, CF6-80C2B4F, CF6-80C2B5F, CF6-
80C2B6, CF6-80C2B6F, CF6-80C2B6FA, CF6-80C2B7F, CF6-80C2D1F, CF6-
80C2L1F, and CF6-80C2K1F turbofan engines with high-pressure turbine 
(HPT) disks with serial numbers listed in Table 1 and 2 of Appendix 
A in GE CF6-80C2 Service Bulletin (SB) 72-1562 R03, dated January 
10, 2018; and Table 1 of Appendix A in GE CF6-80A SB 72-0869 R01, 
dated October 19, 2017.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine/
Turboprop Engine--Turbine Section.

(e) Unsafe Condition

    This AD was prompted by an uncontained failure of an HPT stage 2 
disk. We are issuing this AD to prevent failure of the HPT Stage 1 
disk (CF6-80C2) and the HPT Stage 2 disk (CF6-80C2 and CF6-80A). 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

    After the effective date of this AD, perform an ultrasonic 
inspection (UI) for cracks in stage 1 and stage 2 HPT disks on the 
CF6-80C2 engine model and in stage 2 HPT disks on the CF6-80A engine 
model at each piece-part level exposure in accordance with the 
Accomplishment Instructions, paragraph 3.A.(2), in GE CF6-80C2 SB 
72-1562 R03, dated January 10, 2018, or the Accomplishment 
Instructions, paragraph 3.A.(2) in GE CF6-80A SB 72-0869 R01, dated 
October 19, 2017, as applicable to the engine model.

(h) Non-Required Actions

    The reporting requirements specified in the Accomplishment 
Instructions, paragraphs 3.A.(2)(c) and 3.A.(2)(f), of GE CF6-80C2 
SB 72-1562 R03, dated January 10, 2018, are not required by this AD.

(i) Definition

    For the purpose of this AD, ``piece-part exposure'' of the stage 
1 or stage 2 HPT disk is 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 (j) of this AD. 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 Herman Mak, 
Aerospace Engineer, FAA, ECO Branch, Compliance and Airworthiness 
Division, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7147; fax: 781-238-7199; email: [email protected].
    (2) For service information identified in this AD, contact 
General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: 513-552-3272; email: 
[email protected]. You may view this referenced service 
information at the FAA, Engine and Propeller Standards Branch, 1200 
District Avenue, Burlington, MA 01803. For information on the 
availability of this material at the FAA, call 781-238-7759.

    Issued in Burlington, Massachusetts, on March 23, 2018.
Robert J. Ganley,
Manager, Engine and Propeller Standards Branch, Aircraft Certification 
Service.
[FR Doc. 2018-06390 Filed 3-29-18; 8:45 am]
 BILLING CODE 4910-13-P