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Federal Register / Vol. 86, No. 178 / Friday, September 17, 2021 / Rules and Regulations
St., Des Moines, WA. For information on the availability of this material at the FAA, call 2062313195.
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 fr.inspection@nara.gov, or go to:
https www.archives.gov/federal-register/cfr/
ibr-locations.html.
Issued on August 25, 2021.
Gaetano A. Sciortino, Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.
FR Doc. 202120035 Filed 91621; 8:45 am BILLING CODE 491013P

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration 14 CFR Part 39
Docket No. FAA20190919; Project Identifier 2019NE24AD; Amendment 39
21714; AD 20211813
RIN 2120AA64

Airworthiness Directives; General Electric Company Turbofan Engines Federal Aviation Administration FAA, DOT.
ACTION: Final rule.
AGENCY:

The FAA is adopting a new airworthiness directive AD for all General Electric Company GE CF348
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 5523272;
email: aviation.fleetsupport@ge.com.
You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, SUMMARY:

VerDate Sep<11>2014

15:31 Sep 16, 2021

Jkt 253001

1200 District Avenue, Burlington, MA
01803. For information on the availability of this material at the FAA, call 781 2387759. It is also available at https www.regulations.gov by searching for and locating Docket No.
FAA20190919.

Air, and the Air Line Pilots Association, International ALPA. The following presents the comments received on the NPRM and the FAAs response to each comment.

Request To Change the Initial Compliance Time Examining the AD Docket Horizon Air requested the FAA revise the initial inspection threshold in You may examine the AD docket at proposed paragraph g2 of the NPRM
https www.regulations.gov by to 17,499 flight hours FHs time since searching for and locating Docket No.
FAA20190919; or in person at Docket new TSN or time since repair TSR, or 12,000 flight cycles FCs TSN or TSR, Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal whichever occurs later. Horizon Air reasoned that the initial inspection holidays. The AD docket contains this threshold in paragraph g2 of the final rule, any comments received, and proposed AD would unfairly penalize other information. The address for Docket Operations is U.S. Department of operators, like Horizon Air, with high FH to FC ratios. Horizon Air further Transportation, Docket Operations, M
stated that using the higher FH to FC
30, West Building Ground Floor, Room ratios, the proposed 17,499 FHs TSN or W12140, 1200 New Jersey Avenue SE, TSR inspection threshold would equate Washington, DC 20590.
to approximately 11,000 engine FCs.
FOR FURTHER INFORMATION CONTACT:
This FC value is substantially below the Scott Stevenson, Aviation Safety GE targeted initial engine shop visit Engineer, ECO Branch, FAA, 1200
District Avenue, Burlington, MA 01803; threshold of 12,000 to 14,000 FCs and would potentially result in a significant phone: 781 2387132; fax: 781 238
7199; email: Scott.M.Stevenson@faa.gov. increase in the number of engine shop visits over the 6- to 12-year operating SUPPLEMENTARY INFORMATION:
lifespan of each engine.
The FAA partially agrees. While the Background failure mode is partially related to FCs, The FAA issued a notice of proposed the compliance is published in FHs to rulemaking NPRM to amend 14 CFR
align with existing maintenance part 39 by adding an AD that would intervals. Incorporating both measures apply to all CF348C1, CF348C5, as intervals into this AD is impractical;
CF348C5A1, CF348C5B1, CF34
however, operators may request an 8C5A2, CF348C5A3, CF348E2, CF34 alternative method of compliance 8E2A1, CF348E5, CF348E5A1, CF34 AMOC in accordance with the 8E5A2, CF348E6, and CF348E6A1
procedures specified in paragraph k of model turbofan engines with a certain this AD to use alternate intervals. The combustion outer liner shell installed.
FAA did not change this AD as a result The NPRM published in the Federal of this comment.
Register on January 10, 2020 85 FR
Request To Change the Installation 1292. The NPRM was prompted by Prohibition reports of two IFSDs on GE CF348C
and 8E model turbofan engines. These Horizon Air requested the FAA revise IFSDs were due to the cracking and paragraph h, Installation Prohibition, collapsing of the combustion outer liner as proposed in the NPRM, so it does not shell, which resulted in thermal distress conflict with the proposed required of the high-pressure turbine and lowactions specified in paragraph g1 of pressure turbine LPT including burnthe NPRM. Horizon Air stated that through of the LPT case. In the NPRM, paragraph h of the proposed AD
the FAA proposed to require a BSI or prohibits installation of a combustion visual inspection of the combustion outer liner shell with greater than outer liner shell and, depending on the 17,500 FHs TSN or TSR, without first results of the inspection, possible inspecting it in accordance with replacement of the combustion outer paragraph g1 of the proposed AD.
liner shell. The FAA is issuing this AD
However, paragraph g1 of the to address the unsafe condition on these proposed AD requires inspection of the products.
combustion outer liner shell within 500
engine FHs TSN or TSR for those Discussion of Final Airworthiness combustion outer liner shells that have Directive accumulated 17,500 FHs TSN or TSR.
Comments Horizon Air concluded that the 18,000
FHs TSN or TSR limitation specified in The FAA received comments from four commenters. The commenters were paragraph g1 of the proposed AD
conflicts with the 17,500 FHs TSN or Horizon Air, Japan Airlines, Endeavor
PO 00000

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