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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2022-0516; Project Identifier AD-2022-00262-E]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for all General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines and certain GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. This proposed AD was prompted by the detection of melt-related freckles in the forgings and billets, which may reduce the life of certain rotating compressor discharge pressure (CDP) high-pressure turbine (HPT) seals (rotating CDP seals), interstage HPT rotor seals, and HPT rotor stage 2 disks. This proposed AD would require revising the airworthiness limitations section (ALS) of the applicable GE90-100 Engine Manual (EM) and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate reduced life limits for these parts. This proposed AD would also require the removal and replacement of certain interstage HPT rotor seals, identified by serial number (S/N), installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. The FAA is proposing this AD to address the unsafe condition on these products.
 DATES: The FAA must receive comments on this proposed AD by July 11, 2022.
 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 
                        *https://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:*
                         Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service information identified in this NPRM, contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: 
                        *aviation.fleetsupport@ge.com*; website: 
                        *https://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 (817) 222-5110. Examining the AD Docket You may examine the AD docket at 
                    *https://www.regulations.gov*
                     by searching for and locating Docket No. FAA-2022-0516; 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 NPRM, any comments received, and other information. The street address for Docket Operations is listed above.
 FOR FURTHER INFORMATION CONTACT: Alexei Marqueen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7178; email: 
                        *Alexei.T.Marqueen@faa.gov*.


SUPPLEMENTARY INFORMATION:  Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under 
                    **ADDRESSES**
                    . Include “Docket No. FAA-2022-0516; Project Identifier AD-2022-00262-E” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to 
                    *https://www.regulations.gov,*
                     including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. Confidential Business Information CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Alexei Marqueen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background The FAA was notified by the engine manufacturer of the detection of melt-related freckles in the forgings and billets, which may reduce the life of certain rotating CDP seals, interstage HPT rotor seals, and HPT rotor stage 2 disks on GE90-110B1 and GE90-115B model turbofan engines and may reduce the life of certain interstage HPT rotor seals on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. The manufacturer's investigation determined that, as a result of such freckles forming in the forgings and billets, certain rotating CDP seals, interstage HPT rotor seals, and HPT rotor stage 2 disks (life-limited parts (LLPs)) may have undetected subsurface anomalies that developed during the manufacturing process, 
                    ( print page 32099)
                    resulting in reduced material properties and a lower fatigue life capability. Reduced material properties may cause premature LLP fracture, which could result in uncontained debris release. As a result of its investigation, the manufacturer determined the need to reduce the life limits of certain LLPs. To reflect these reduced life limits, the manufacturer revised the ALS of the affected GE90-100 EMs. Additionally, the manufacturer published service information that specifies procedures for the removal and replacement of certain interstage HPT rotor seals installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. This condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane. FAA's Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. Related Service Information The FAA reviewed GE GE90-100 Service Bulletin (SB) 72-0851 R00, dated August 17, 2021. This SB provides the reduced life limits for certain LLPs. The FAA also reviewed GE GE90 SB 72-1211 R00, dated March 9, 2022. This SB describes procedures for removing and replacing certain interstage HPT rotor seals. Proposed AD Requirements in This NPRM This proposed AD would require revising the ALS of the applicable GE90-100 EM and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate reduced life limits for certain LLPs. This proposed AD would also require the removal and replacement of certain interstage HPT rotor seals. Differences Between This Proposed AD and the Service Information GE90-100 SB 72-0851 R00, dated August 17, 2021, uses the term “HPT rotor interstage seals,” while this proposed AD uses the term “interstage HPT rotor seals.” Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 248 engines installed on airplanes of U.S. registry. The FAA estimates that zero engines installed on airplanes of U.S. registry would require replacement of the interstage HPT rotor seal. The FAA estimates the following costs to comply with this proposed AD: Estimated Costs
Action
Labor cost
Parts cost
Cost per 
                             product
Cost on U.S. 
                             operatorsRevise ALS of EM and the operator's existing approved maintenance program or inspection program
1 work-hour × $85 per hour = $85
$0
$85
$21,080Replace interstage HPT rotor seal
1,500 work-hours × $85 per hour = $127,500
286,331
413,831
0
 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 The FAA 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) Would not affect intrastate aviation in Alaska, and (3) Would 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
 1.The authority citation for part 39 continues to read as follows: Authority:
                    49 U.S.C. 106(g), 40113, 44701. § 39.13
 2.The FAA amends § 39.13 by adding the following new airworthiness directive: **General Electric Company:**
                         Docket No. FAA-2022-0516; Project Identifier AD-2022-00262-E. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by July 11, 2022. (b) Affected ADs None. (c) Applicability This AD applies to: (1) General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines; and (2) GE GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines with an installed interstage high-pressure turbine (HPT) rotor seal with part number (P/N) 2629M47P01 and serial number (S/N) NCU5430D. (d) Subject Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section, and JASC Code 7250, Turbine Section. (e) Unsafe Condition This AD was prompted by the detection of melt-related freckles in the forgings and 
                        ( print page 32100)
                        billets, which may reduce the life of certain rotating compressor discharge pressure (CDP) HPT seals (rotating CDP seal), interstage HPT rotor seals, and HPT rotor stage 2 disks. The FAA is issuing this AD to prevent failure of the rotating CDP seal, interstage HPT rotor seal, and HPT rotor stage 2 disk. The unsafe condition, if not addressed, could result in uncontained debris 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 (1) For affected GE90-110B1 and GE90-115B model turbofan engines, within 90 days after the effective date of this AD, revise the airworthiness limitations section (ALS) of the existing GE90-100 Engine Manual (EM) and the operator's existing approved maintenance program or inspection program, as applicable, by inserting the following information: (i) For rotating CDP seal P/N 2479M03P01, insert the information in Table 1 to paragraph (g)(1)(i) of this AD.  (ii) For interstage HPT rotor seal P/N 2505M72P01, insert the information in Table 2 to paragraph (g)(1)(ii) of this AD. 
 
  (iii) For HPT rotor stage 2 disk P/N 2505M73P03, insert the information in Table 3 to paragraph (g)(1)(iii) of this AD. 
 
  (2) For affected GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines, before the interstage HPT rotor seal, P/N 2629M47P01 and S/N NCU5430D, accumulates 7,400 cycles since new, remove the affected interstage HPT rotor seal from service and replace with a part eligible for installation. (h) Definitions For the purpose of this AD, a “part eligible for installation” is any interstage HPT rotor seal that does not have P/N 2629M47P01 and S/N NCU5430D. (i) 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)(1) of this AD and email to: 
                        *ANE-AD-AMOC@faa.gov.* (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. (j) Related Information (1) For more information about this AD, contact Alexei Marqueen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7178; email: 
                        *Alexei.T.Marqueen@faa.gov*.
                        ( print page 32103) (2) For service information identified in this AD, contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: 
                        *aviation.fleetsupport@ge.com*; website: 
                        *https://www.ge.com.*
                         You may view this referenced 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 (817) 222-5110. Issued on May 5, 2022. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service.


BILLING CODE 4910-13-P [FR Doc. 2022-11346 Filed 5-26-22; 8:45 am] BILLING CODE 4910-13-C