Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 85, Number 210 (Thursday, October 29, 2020)]
[Rules and Regulations]
[Pages 68431-68434]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-23947]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0592; Project Identifier 2019-NE-19-AD; Amendment 
39-21298; AD 2020-22-02]
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 all 
General Electric Company (GE) CF6-80C2A5F, -80C2B1F, -80C2B2F, -
80C2B4F, -80C2B5F, -80C2B6F, -80C2B6FA, -80C2B7F, -80C2B8F, -80C2D1F, -
80C2K1F, -80C2L1F, -80E1A2, -80E1A3, -80E1A4, and -80E1A4/B model 
turbofan engines with a certain hydromechanical unit (HMU) installed. 
This AD was prompted by a report of fuel coking of the HMU fuel 
metering valve (FMV) electro-hydraulic servo valves (EHSV) resulting in 
tailpipe fire. This AD requires removal of the HMU and its replacement 
with a part eligible for installation. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective December 3, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of December 3, 
2020.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: 513-552-3272; email: [email protected]. 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 on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0592.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0592; 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: Stephen Elwin, Aerospace Engineer, ECO 
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7236; fax: 781-238-7199; email: [email protected].

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 GE CF6-80C2A5F, -
80C2B1F, -80C2B2F, -80C2B4F, -80C2B5F, -80C2B6F, -80C2B6FA, -80C2B7F, -
80C2B8F, -80C2D1F, -80C2K1F, -80C2L1F, -80E1A2, -80E1A3, -80E1A4, and -
80E1A4/B model turbofan engines with a certain HMU installed. The NPRM 
published in the Federal Register on September 6, 2019 (84 FR 46896). 
The NPRM was prompted by a report of fuel coking of the HMU FMV EHSV 
resulting in tailpipe fire. The NPRM proposed to require the removal of 
the HMU and its replacement with a part eligible for installation. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Update Applicability To Exclude Engines With Updated 
Electronic Control Unit (ECU) Software

    GE requested that the FAA update paragraph (c), Applicability, of 
this AD, to include ``For CF6-80E engines that have complied with [GE 
Service Bulletin (SB)] CF6-80E1 SB 73-0129 `Introduction of ECU 
Software Version E.1.Q' no action is required.'' GE reasoned that CF6-
80E1 ECU Software Version E.1.Q was designed to avoid tailpipe fires 
caused by the malfunction of the HMU FMV EHSV. There have been no 
reported tailpipe fires on GE CF6-80E1 model turbofan engines that have 
installed ECU Software Version E.1.Q.
    The FAA disagrees with updating the applicability of this AD to 
exclude engines with updated ECU Software Version E.1.Q. Although GE 
CF6-80E1 ECU Software Version E.1.Q addresses the known sequence of 
tailpipe fires by monitoring the HMU FMV position at low N2 speeds, 
which may relate to the unsafe condition in this AD, the FAA would need 
additional data that shows how the ECU software update addresses the 
potential for this failure to occur at other phases of flight. If the 
data reveal information relevant to this unsafe condition, the FAA will 
consider future rulemaking. The FAA did not change this AD.

Request To Allow Modification of the HMU as an Alternative Method of 
Compliance (AMOC)

    An anonymous commenter requested that the FAA consider whether the

[[Page 68432]]

modification of the HMU using GE CF6-80C2 SB 73-0378 R00, dated July 
14, 2010 (``GE SB 73-0378''), is an AMOC [alternative method of 
compliance] to this AD. The commenter reasoned that the modification 
results in an HMU FMV EHSV with a new part number (P/N).
    The FAA disagrees. GE SB 73-0378 introduces material properties to 
the HMU that improves corrosion resistance. GE SB 73-0378 does not, 
however, require the installation of a new or overhauled HMU FMV EHSV. 
The HMU with improved corrosion resistance introduced by GE SB 73-0378 
is not related to the unsafe condition of this AD. Additionally, 
although GE SB 73-0378 results in a new HMU P/N after modification of 
the HMU, this AD still applies to this new P/N.

Request To Change the Compliance Time

    Honeywell requested that the FAA reduce the compliance time of 
paragraph (g), Required Actions, of this AD from 40,000 to 20,000 
flight hours (FHs) since new or since last overhaul.
    The FAA disagrees. The FAA does not have data to support reducing 
the removal and replacement of the HMU from 40,000 FHs to 20,000 FHs. 
According to reports from GE, which were considered by the FAA when 
preparing the NPRM, the related tailpipe fire incidents occurred in 
engines with HMUs exceeding 40,000 FHs since new or since the last 
overhaul. The FAA did not change this AD.
    Delta Air Lines (DAL) requested that the FAA increase the initial 
compliance time to remove and replace the HMU from 180 days to 12 
months or to a number of hours or cycles greater than 40,000 FHs, based 
on the level of risk. DAL stated that they have attempted to purchase 
additional units to support the compliance time of 40,000 FHs or 180 
days proposed in the NPRM; however, there are few spares on the market. 
Additionally, DAL reasoned that the turnaround time for an overhaul of 
the HMU has not allowed DAL to progress as fast as required to meet the 
expected compliance deadline for units in their fleet.
    Atlas Air Inc. (Atlas Air) also indicated that the volume of HMUs 
wherein operators will be unable to determine HMU FMV EHSV compliance 
will exceed the available compliant spares in the market. The lack of 
available HMUs will cause the grounding of a significant number of 
aircraft unless the AD allows for the completed overhaul to count as 
evidence of compliance (EoC) as documented by FAA Form 8130-3, 
Authorized Release Certificate, Airworthiness Approval Tag.
    The FAA disagrees with increasing the compliance time for the 
required actions of this AD. The FAA infers that DAL's and Atlas Air's 
request to increase the compliance time of this AD, while mentioning 
the lack of spares and delays with the overhaul of the HMU, is the 
result of the definition of ``an overhaul of the HMU'' in paragraph 
(h)(2), Definitions, in the NPRM. The concern is that operators do not 
track usage time on the HMU FMV EHSV separately from the HMU and, 
therefore, would need to replace the complete HMU in all scenarios 
within 180 days. The FAA changed the definition of ``an overhaul of the 
HMU'' in this AD to clarify the methods that an HMU may be overhauled.

Request To Require Complete Overhaul of HMU

    Honeywell requested that the FAA revise the definition of ``an 
overhaul of the HMU'' in the Definitions, paragraph (h)(2), of this AD, 
to clarify that an overhaul of the HMU is a ``complete overhaul'' of 
the HMU rather than just an overhaul of HMU FMV EHSV.
    Based on its requested change to the definition, Honeywell also 
requested that the FAA add additional estimated costs to the Cost of 
Compliance section of this AD to include the estimated costs of a 
complete HMU overhaul.
    The FAA agrees that performing a complete overhaul of the HMU 
addresses the unsafe condition of this AD. The FAA disagrees with 
requiring a complete overhaul of the HMU as only an overhaul of the HMU 
FMV EHSV is required to prevent fuel coking or fuel deposits in the HMU 
FMV EHSV. The FAA, however, changed the definition of ``an overhaul of 
the HMU'' to include either overhaul of the HMU (complete) or overhaul 
of the HMU FMV EHSV. The FAA added an estimate for the cost of a 
complete HMU overhaul since this is an acceptable means of complying 
with the requirements of this AD.

Request To Clarify the Definition of an Overhaul of the HMU

    Several commenters requested clarification, as described below, of 
the definition of ``an overhaul of the HMU'' provided in paragraph 
(h)(2) of this AD.

Clarification of Other FAA-Approved Methods

    FedEx Express (FedEx) and United Airlines (UAL) requested that the 
FAA clarify overhauled by ``other FAA-approved methods.'' FedEx asked 
what is the intended scope of this phrase and if it includes 
accomplishment of earlier revisions of GE SB CF6-80C2 SB 73-0436, as 
well as work performed using the applicable component maintenance 
manual (CMM) which was classified as an overhaul in block 11 of FAA 
Form 8130-3, Authorized Release Certificate, Airworthiness Approval Tag 
(or equivalent). UAL also asked if ``other FAA-approved methods'' 
included work accomplished using the CMM for the HMU FMV EHSV.
    The FAA agrees ``other FAA-approved methods'' was unclear and has 
removed it from the definition for ``an overhaul of the HMU.'' The FAA 
added a credit for previous actions paragraph to provide credit for the 
initial removal and replacement required actions contained in paragraph 
(g)(1) of this AD if the HMU FMV EHSV was overhauled before the 
effective date of this AD using GE SB CF6-80C2 SB 73-0436 R01, dated 
May 14, 2019, or GE SB CF6-80C2 73-0142 R01, dated May 14, 2019. The 
FAA also changed the definition of ``an overhaul of the HMU'' in this 
AD to clarify that an HMU may be overhauled using Honeywell-approved 
maintenance procedures.

Clarification of Approved Facility

    DAL, Kalitta Air Group (Kalitta Air), and United Parcel Service 
(UPS) requested that an overhaul of the HMU at an FAA or Honeywell-
approved facility be considered an overhaul of the HMU that resets the 
40,000 FHs requirement.
    The FAA agrees and clarified the definition of ``an overhaul of the 
HMU'' in this AD to include ``An overhaul of the HMU (complete) using 
Honeywell-approved maintenance procedures.''

Clarification That HMU Overhaul Includes HMU EHSVs

    All Nippon Airways (ANA) asked if an overhaul of the HMU includes 
overhauling all HMU EHSVs.
    The FAA agrees that the overhaul of the HMU includes overhauling 
all HMU EHSVs. The FAA changed the definition of ``an overhaul of the 
HMU'' to include either overhaul of the HMU (complete) or overhaul of 
the HMU FMV EHSV. The FAA notes, however, that complete overhaul of the 
HMU is not required by this AD.

Clarification of Tracking of HMU FMV EHSVs

    ANA, Atlas Air, DAL, FedEx, Kalitta Air, Thai Airways, and UPS 
stated that the HMU EHSVs are sub-assemblies of the HMU and repair or 
overhaul of these sub-components is not typically tracked separately 
from the HMU at an engine shop visit level. Therefore, overhaul of

[[Page 68433]]

the HMU FMV EHSV is not recorded by most operators in a separate 
maintenance program record. The commenters reasoned that they received 
FAA Form 8130-3, Authorized Release Certificate, Airworthiness Approval 
Tag, documenting the HMU approval for return to service, but FAA Form 
8130-3 does not include information about the EHSVs within the HMU. 
Atlas Air suggested that if the time since the most recent replacement 
of the HMU FMV EHSVs cannot be determined, then the time since overhaul 
(TSO) based on FAA Form 8130-3 be used as EoC to the AD for HMUs 
overhauled before the effective date of this AD.
    The FAA acknowledges that the HMU FMV EHSVs are not typically 
tracked separately from the HMU. The FAA agrees that in cases where the 
overhaul of the HMU FMV EHSV cannot be determined, the TSO can be used 
as EoC to the AD for HMUs overhauled before the effective date of this 
AD. The FAA changed the definition of ``an overhaul of the HMU'' to 
include either overhaul of the HMU (complete) or overhaul of the HMU 
FMV EHSV.

Request To Clarify Previous Compliance With the AD

    DAL stated that paragraph (f) of this AD states, ``Comply with this 
AD within the compliance times specified, unless already done.'' Yet, 
the NPRM does not address what constitutes previous compliance.
    The FAA notes that ``unless already done,'' as used in this AD, 
means performing the actions in paragraph (g), Required Actions, before 
the effective date of this AD.

Request To Clarify if This AD Affects SAIB NE-09-25R2

    An anonymous commenter asked if this AD affects the following 
statements in SAIB NE-09-25R2: ``The FAA has determined that the 
performance properties of aviation turbine fuel are not impacted with 
up to 50 mg/kg of FAME [fatty acid methyl ester] under continuous usage 
. . .'' and ``At high enough concentrations, FAME can impact the 
thermal stability of the fuel that could lead to coke deposits in the 
fuel system.''
    While FAME can impact the thermal stability of the fuel, leading to 
coke deposits in the fuel system, the HMU FMV EHSV fuel coking and fuel 
deposits of this AD is not related to FAME. The HMU FMV EHSV fuel 
coking and fuel deposits unsafe condition of this AD neither 
substantiates nor refutes SAIB NE-09-25R2. Therefore, this AD does not 
affect the SAIB guidance.

Support for the AD

    The Boeing Company and The Air Line Pilots Association, 
International, expressed support for the AD as written.
    An anonymous commenter disagreed with Honeywell's suggestion to 
remove the HMU for a complete overhaul before reaching 20,000 FHs 
considering the root cause analysis is identified as high-time wear 
failure of the HMU FMV EHSV. The FAA infers that this comment 
represents support for the AD as written.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the changes described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Service Information Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed GE SB CF6-80C2 SB 73-0436 R02, dated August 15, 
2019, and GE SB CF6-80E1 SB 73-0142 R02, dated August 15, 2019. The SBs 
provide instructions, differentiated by the turbofan engine model, for 
repetitive overhauls of the HMU FMV EHSVs. 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 
the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 573 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
----------------------------------------------------------------------------------------------------------------
Removal and replacement of HMU......  5 work-hours x $85 per               $0             $425         $243,525
                                       hour = $425.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary overhaul. 
The FAA has no way of determining the number of aircraft that might 
perform the overhaul of the HMU FMV EHSV or overhaul of the complete 
HMU:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Overhaul HMU FMV EHSV.........................  5 work-hours x $85 per hour =             $4,000          $4,425
                                                 $425.
Overhaul HMU (complete).......................  25 work-hours x $85 per hour =            92,875          95,000
                                                 $2,125.
----------------------------------------------------------------------------------------------------------------

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.

[[Page 68434]]

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) 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 (AD):

2020-22-02 General Electric Company: Amendment 39-21298; Docket No. 
FAA-2019-0592; Project Identifier 2019-NE-19-AD.

(a) Effective Date

    This AD is effective December 3, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all General Electric Company (GE) CF6-
80C2A5F, -80C2B1F, -80C2B2F, -80C2B4F, -80C2B5F, -80C2B6F, -
80C2B6FA, -80C2B7F, -80C2B8F, -80C2D1F, -80C2K1F, -80C2L1F, -80E1A2, 
-80E1A3, -80E1A4, and -80E1A4/B model turbofan engines with a 
hydromechanical unit (HMU) with a part number (P/N) listed in 
paragraph 1.A., Table 1, of GE Service Bulletin (SB) CF6-80C2 SB 73-
0436 R02, dated August 15, 2019; or paragraph 1.A., Table 1, of GE 
SB CF6-80E1 SB 73-0142 R02, dated August 15, 2019; installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7300, Engine Fuel 
and Control.

(e) Unsafe Condition

    This AD was prompted by a report of fuel coking of the HMU fuel 
metering valve (FMV) electro-hydraulic servo valve (EHSV) resulting 
in tailpipe fire. The FAA is issuing this AD to prevent fuel coking 
or fuel deposits in the HMU FMV EHSV. The unsafe condition, if not 
addressed, could result in failure of the HMU, engine fire, and 
damage to the airplane.

(f) Compliance

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

(g) Required Actions

    (1) Remove the HMU and replace with a part eligible for 
installation before reaching 40,000 flight hours (FHs) since new or 
since the last overhaul, or within 180 days after the effective date 
of this AD, whichever is later. If the FHs since new or last 
overhaul are unknown and unable to be determined, replace the HMU 
with a part eligible for installation within 180 days after the 
effective date of this AD.
    (2) Thereafter, remove the HMU before reaching 40,000 FHs since 
new or since the last overhaul and replace with a part eligible for 
installation.

(h) Definitions

    (1) For the purpose of this AD, a ``part eligible for 
installation'' is an HMU that has fewer than 40,000 FHs since new or 
fewer than 40,000 FHs since an overhaul of the HMU.
    (2) For the purpose of this AD, ``an overhaul of the HMU'' is 
one of the following:
    (i) An overhaul of the HMU (complete) using Honeywell-approved 
maintenance procedures; or
    (ii) An overhaul of the HMU FMV EHSV using the Accomplishment 
Instructions, paragraph 3.C.(3), of GE SB CF6-80C2 SB 73-0436 R02, 
dated August 15, 2019, or paragraph 3.C.(3), of GE SB CF6-80E1 SB 
73-0142 R02, dated August 15, 2019.

(i) Credit for Previous Action

    You may take credit for the initial removal and replacement of 
the HMU required by paragraph (g)(1) of this AD if the HMU FMV EHSV 
was overhauled before the effective date of this AD using GE SB CF6-
80C2 SB 73-0436 R01, dated May 14, 2019, or GE SB CF6-80C2 73-0142 
R01, dated May 14, 2019.

(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) 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

    For more information about this AD, contact Stephen Elwin, 
Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: 781-238-7236; fax: 781-238-7199; email: 
[email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) General Electric (GE) Service Bulletin (SB) CF6-80C2 SB 73-
0436 R02, dated August 15, 2019.
    (ii) GE SB CF6-80E1 SB 73-0142 R02, dated August 15, 2019.
    (3) For GE service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: 513-552-3272; email: [email protected].
    (4) You may view this service information at 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 13, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-23947 Filed 10-28-20; 8:45 am]
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