Rule2021-20042
Airworthiness Directives; General Electric Company Turbofan Engines
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 17, 2021
Effective
October 22, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for all General Electric Company (GE) CF34-8 model turbofan engines with a certain outer shell combustion liner (combustion outer liner shell) installed. This AD was prompted by two in-flight engine shutdowns (IFSDs) that occurred as a result of failures of the combustion outer liner shell. This AD requires a borescope inspection (BSI) or visual inspection of the combustion outer liner shell and, depending on the results of the inspection, possible replacement of the combustion outer liner shell. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 178 (Friday, September 17, 2021)</title>
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[Federal Register Volume 86, Number 178 (Friday, September 17, 2021)]
[Rules and Regulations]
[Pages 51792-51795]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-20042]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2019-0919; Project Identifier 2019-NE-24-AD; Amendment
39-21714; AD 2021-18-13]
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) CF34-8 model turbofan engines with a
certain outer shell combustion liner (combustion outer liner shell)
installed. This AD was prompted by two in-flight engine shutdowns
(IFSDs) that occurred as a result of failures of the combustion outer
liner shell. This AD requires a borescope inspection (BSI) or visual
inspection of the combustion outer liner shell and, depending on the
results of the inspection, possible replacement of the combustion outer
liner shell. The FAA is issuing this AD to address the unsafe condition
on these products.
DATES: This AD is effective October 22, 2021.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of October 22,
2021.
ADDRESSES: For service information identified in this final rule,
contact General Electric Company, GE Aviation, Room 285, 1 Neumann Way,
Cincinnati, OH 45215; phone: (513) 552-3272; email:
<a href="/cdn-cgi/l/email-protection#a6c7d0cfc7d2cfc9c888c0cac3c3d2d5d3d6d6c9d4d2e6c1c388c5c9cb"><span class="__cf_email__" data-cfemail="7716011e16031e181959111b121203040207071805033710125914181a">[email protected]</span></a>. 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a> by searching for and
locating Docket No. FAA-2019-0919.
Examining the AD Docket
You may examine the AD docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2019-0919; 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: Scott Stevenson, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7132; fax: (781) 238-7199; email:
<a href="/cdn-cgi/l/email-protection#095a6a667d7d2744275a7d6c7f6c677a6667496f6868276e667f"><span class="__cf_email__" data-cfemail="1a4979756e6e345734496e7f6c7f746975745a7c7b7b347d756c">[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 CF34-8C1, CF34-8C5,
CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-8E2A1,
CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model
turbofan engines with a certain combustion outer liner shell installed.
The NPRM published in the Federal Register on January 10, 2020 (85 FR
1292). The NPRM was prompted by reports of two IFSDs on GE CF34-8C and
-8E model turbofan engines. These IFSDs were due to the cracking and
collapsing of the combustion outer liner shell, which resulted in
thermal distress of the high-pressure turbine and low-pressure turbine
(LPT) including burn-through of the LPT case. In the NPRM, the FAA
proposed to require a BSI or visual inspection of the combustion outer
liner shell and, depending on the results of the inspection, possible
replacement of the combustion outer liner shell. 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 four commenters. The commenters were
Horizon Air, Japan Airlines, Endeavor Air, 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 Change the Initial Compliance Time
Horizon Air requested the FAA revise the initial inspection
threshold in proposed paragraph (g)(2) of the NPRM to ``17,499 flight
hours (FHs) time since new (TSN) or time since repair (TSR), or 12,000
flight cycles (FCs) TSN or TSR, whichever occurs later.'' Horizon Air
reasoned that the initial inspection threshold in paragraph (g)(2) of
the proposed AD would unfairly penalize operators, like Horizon Air,
with high FH to FC ratios. Horizon Air further stated that using the
higher FH to FC ratios, the proposed 17,499 FHs TSN or TSR inspection
threshold would equate to approximately 11,000 engine FCs. This FC
value is substantially below the GE targeted initial engine shop visit
threshold of 12,000 to 14,000 FCs and would potentially result in a
significant increase in the number of engine shop visits over the 6- to
12-year operating lifespan of each engine.
The FAA partially agrees. While the failure mode is partially
related to FCs, the compliance is published in FHs to align with
existing maintenance intervals. Incorporating both measures as
intervals into this AD is impractical; however, operators may request
an alternative method of compliance (AMOC) in accordance with the
procedures specified in paragraph (k) of this AD to use alternate
intervals. The FAA did not change this AD as a result of this comment.
Request To Change the Installation Prohibition
Horizon Air requested the FAA revise paragraph (h), Installation
Prohibition, as proposed in the NPRM, so it does not conflict with the
proposed required actions specified in paragraph (g)(1) of the NPRM.
Horizon Air stated that paragraph (h) of the proposed AD prohibits
installation of a combustion outer liner shell with greater than 17,500
FHs TSN or TSR, without first inspecting it in accordance with
paragraph (g)(1) of the proposed AD. However, paragraph (g)(1) of the
proposed AD requires inspection of the combustion outer liner shell
within 500 engine FHs TSN or TSR for those combustion outer liner
shells that have accumulated 17,500 FHs TSN or TSR. Horizon Air
concluded that the 18,000 FHs TSN or TSR limitation specified in
paragraph (g)(1) of the proposed AD conflicts with the 17,500 FHs TSN
or
[[Page 51793]]
TSR limit specified in paragraph (h) of the proposed AD.
The FAA disagrees. The initial inspection threshold is 17,500 FHs
for affected engines. This AD provides a grace period of 500 FHs for
in-service engines to prevent the unintentional grounding of airplanes
with affected engines. The FAA did not change this AD as a result of
this comment.
Request To Include a Terminating Action
Horizon Air requested the FAA petition GE for a terminating action
to the inspection requirements in the proposed AD. Horizon Air
commented the financial cost and maintenance burden of performing the
repetitive inspections are significant.
The FAA disagrees. The FAA considers this AD to be interim action
and will consider further rulemaking if the manufacturer develops a
terminating action. The FAA included all estimated costs in the Costs
of Compliance section in the preamble of this AD. The FAA did not
change this AD as a result of this comment.
Request To Revise Service Information References
Horizon Air, Japan Airlines, and Endeavor Air requested the FAA
update references to GE CF34-8E Alert Service Bulletin (SB) 72-A0221
and GE CF34-8C Alert SB 72-A0335 in the Required Actions section,
paragraph (g), of the proposed AD. Japan Airlines requested that GE
CF34-8E-AL S/B 72-A0221, Original Issue, dated June 27, 2019, be added
to the compliance paragraphs because the Original Issue and R01 have
the same inspection methods and limits. Horizon Air requested that the
FAA reference only GE CF34-8E Alert SB 72-A0221 R01 in paragraph (g) of
the proposed AD and add a Previous Credit section to allow previous
compliance using the Original Issue. Endeavor Air requested that the
FAA reference the latest revision of GE CF34-8C Alert SB 72-A0335 in
proposed paragraph (g). Endeavor Air indicated that GE planned to issue
R02 of CF34-8C Alert SB 72-A0335 on February 24, 2020.
The FAA agrees to reference the latest revision of these Alert SBs,
which is R02 for both GE CF34-8C Alert SB 72-A0335 and GE CF34-8E Alert
SB 72-A0221, in paragraph (g) of this AD. The FAA disagrees with the
need to reference prior revisions of these Alert SBs in paragraphs (g)
of this AD but agrees to add Credit for Previous Actions, paragraph
(j), to this AD to allow credit for performing inspections prior to the
effective date of this AD. These changes impose no additional burden on
operators who are required to comply with this AD.
Request To Clarify Compliance
Japan Airlines requested that the FAA clarify whether the
inspection should occur ``before'' or ``within'' 500 FHs after the
effective date of this AD. Japan Airlines reasoned that the service
bulletin specifies to inspect ``before'' 500 FHs, while the NPRM
proposed to inspect ``within'' 500 FHs.
The FAA agrees. The FAA revised Required Actions, paragraphs (g)(1)
and (2) of this AD to specify, ``before accumulating 500 engine FHs.''
Support for the AD
ALPA expressed support for the NPRM as written.
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 Under 1 CFR Part 51
The FAA reviewed General Electric CF34-8C Alert SB 72-A0335 R02 and
General Electric CF34-8E Alert SB 72-A0221 R02, both dated February 25,
2020. The Alert SBs specify procedures for performing a BSI of the
combustion outer liner shell. These documents are distinct since they
apply to different engine models. 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.
Interim Action
The FAA considers this AD to be an interim action. If final action
is later identified, the FAA might consider further rulemaking.
Costs of Compliance
The FAA estimates that this AD affects 1,535 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
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BSI or visually inspect the combustion 3 work-hours x $85 per $0 $255 $391,425
outer liner shell. hour = $255.
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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
inspection. The agency has no way of determining the number of engines
that might need this replacement:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
----------------------------------------------------------------------------------------------------------------
Replace the combustion outer liner shell...... 812 work-hours x $85 per hour = $80,000 $149,020
$69,020.
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[[Page 51794]]
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.
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:
2021-18-13 General Electric Company: Amendment 39-21714; Docket No.
FAA-2019-0919; Project Identifier 2019-NE-24-AD.
(a) Effective Date
This airworthiness directive (AD) is effective October 22, 2021.
(b) Affected ADs
None.
(c) Applicability
This AD applies to General Electric Company (GE) CF34-8C1, CF34-
8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-
8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1
model turbofan engines with an outer shell combustion liner
(combustion outer liner shell), part number (P/N) 4124T04G04, P/N
4124T04G05, or P/N 5159T35G02, installed.
(d) Subject
Joint Aircraft System Component (JASC) Code 7240, Turbine Engine
Combustion Section.
(e) Unsafe Condition
This AD was prompted by two in-flight engine shutdowns (IFSDs)
that occurred as a result of failures of the combustion outer liner
shell. The FAA is issuing this AD to prevent failure of the
combustion outer liner shell. The unsafe condition, if not
addressed, could result in burn-through of the low-pressure turbine
case, 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) For an affected engine with a combustion outer liner shell
that on the effective date of this AD has accumulated 17,500 flight
hours (FHs) or greater time since new (TSN), or time since repair
(TSR), perform an initial borescope inspection (BSI) or visual
inspection of the combustion outer liner shell for cracks before
accumulating 500 engine FHs after the effective date of this AD.
(i) For GE CF34-8C engines, inspect using the Accomplishment
Instructions, paragraphs 3.A.(4) and 3.A.(5), of GE CF34-8C Alert
Service Bulletin (SB) 72-A0335 R02, dated February 25, 2020 (CF34-8C
Alert SB 72-A0335).
(ii) For GE CF34-8E engines, inspect using the Accomplishment
Instructions, paragraphs 3.A.(4) and 3.A.(5), of GE CF34-8E Alert SB
72-A0221 R02, dated February 25, 2020 (CF34-8E Alert SB 72-A0221).
Note 1 to paragraph (g)(1): GE has identified the service
information as an ``Alert Service Bulletin,'' which is stated only
in the body of the Alert SB.
(2) For an affected engine with a combustion outer liner shell
that on the effective date of this AD has accumulated 17,499 FHs or
fewer TSN or TSR, before accumulating 500 engine FHs after the
combustion outer liner shell has accumulated 17,500 FHs TSN or TSR,
perform an initial BSI or visual inspection on the combustion outer
liner shell for cracks.
(i) For GE CF34-8C engines, inspect using the Accomplishment
Instructions, paragraphs 3.A.(4) and 3.A.(5), of CF34-8C Alert SB
72-A0335.
(ii) For GE CF34-8E engines, inspect using the Accomplishment
Instructions paragraphs 3.A.(4) and 3.A.(5), of CF34-8E Alert SB 72-
A0221.
(3) For an affected engine with a combustion outer liner shell
for which it is not possible to determine the TSN or TSR, use the
engine FHs since new to determine when to perform the initial BSI or
visual inspection.
(4) After the effective date of this AD, and after the initial
inspection required by paragraph (g)(1) or (2) of this AD, re-
inspect or remove the combustion outer liner shell using inspection
criteria as follows:
(i) For GE CF34-8C engines, use Table 1 of CF34-8C Alert SB 72-
A0335.
(ii) For GE CF34-8E engines, use Table 1 of CF34-8E Alert SB 72-
A0221.
(h) Installation Prohibition
After the effective date of this AD, do not install a combustion
outer liner shell with greater than 17,500 FHs TSN or TSR without
first inspecting the combustion outer liner shell in accordance with
paragraph (g)(1) of this AD.
(i) Definition
For the purpose of this AD, ``time since repair (TSR)'' is the
amount of FHs accumulated on the combustion outer liner shell since
performing GEK 105091 or GEK 112031, 72-44-06, REPAIR 023.
(j) Credit for Previous Actions
You may take credit for any initial BSI or visual inspection of
the combustion outer liner shell required by paragraphs (g)(1) and
(2) of this AD if you performed the initial BSI or visual inspection
before the effective date of this AD using:
(1) GE CF34-8C-AL S/B 72-A0335, Original Issue, dated June 27,
2019;
(2) GE CF34-8C Alert SB 72-A0335 R01, dated September 23, 2019;
(3) GE CF34-8E-AL S/B 72-A0221, Original Issue, dated June 27,
2019; or
(4) GE CF34-8E Alert SB 72-A0221 R01, dated September 23, 2019.
(k) 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 Related Information. You may email your request to:
<a href="/cdn-cgi/l/email-protection#9ddcd3d8b0dcd9b0dcd0d2deddfbfcfcb3faf2eb"><span class="__cf_email__" data-cfemail="90d1ded5bdd1d4bdd1dddfd3d0f6f1f1bef7ffe6">[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.
[[Page 51795]]
(l) Related Information
For more information about this AD, contact Scott Stevenson,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7132; fax: (781) 238-7199;
email: <a href="/cdn-cgi/l/email-protection#2073434f54540e6d0e73544556454e534f4e604641410e474f56"><span class="__cf_email__" data-cfemail="c596a6aab1b1eb88eb96b1a0b3a0abb6aaab85a3a4a4eba2aab3">[email protected]</span></a>.
(m) 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) GE CF34-8C Alert Service Bulletin (SB) 72-A0335 R02, dated
February 25, 2020.
(ii) GE CF34-8E Alert SB 72-A0221 R02, dated February 25, 2020.
(3) For GE 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:
<a href="/cdn-cgi/l/email-protection#ceafb8a7afbaa7a1a0e0a8a2ababbabdbbbebea1bcba8ea9abe0ada1a3"><span class="__cf_email__" data-cfemail="2f4e59464e5b4640410149434a4a5b5c5a5f5f405d5b6f484a014c4042">[email protected]</span></a>.
(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: <a href="/cdn-cgi/l/email-protection#d7b1a5f9beb9a4a7b2b4a3beb8b997b9b6a5b6f9b0b8a1"><span class="__cf_email__" data-cfemail="096f7b2760677a796c6a7d6066674967687b68276e667f">[email protected]</span></a>, or go to: <a href="https://www.archives.gov/federal-register/cfr/ibr-locations.html">https://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on August 26, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-20042 Filed 9-16-21; 8:45 am]
BILLING CODE 4910-13-P
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