AD 2022-07-15

22438 Federal Register / Vol. 87, No. 73 / Friday, April 15, 2022 / Rules and Regulations opinion, or expert testimony relating to official information, or for production of official records or information, in legal proceedings in which the United States or the DNFSB is not a named party. However, it does not apply to: * * * * * Dated: April 12, 2022. Joyce Connery, Chairperson. [FR Doc. 2022–08133 Filed 4–14–22; 8:45 am] BILLING CODE P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2022–0389; Project Identifier MCAI–2022–00291–T; Amendment 39–22003; AD 2022–07–15] RIN 2120–AA64 Airworthiness Directives; Airbus SAS Airplanes AGENCY : Federal Aviation Administration (FAA), DOT. ACTION : Final rule; request for comments. SUMMARY : The FAA is adopting a new airworthiness directive (AD) for all Airbus SAS Model A318, A319, A320, and A321 series airplanes. This AD was prompted by the detection of several channel failures on a newly developed braking and steering control unit (BSCU). This AD requires replacing affected BSCUs and revising the operator’s existing FAA-approved minimum equipment list (MEL), as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. This AD also limits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products. DATES : This AD becomes effective May 2, 2022. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 2, 2022. The FAA must receive comments on this AD by May 31, 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: 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 EASA material incorporated by reference (IBR) in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may find this IBR material on the EASA website at https://ad.easa.europa.eu. For Airbus SAS material IBR in this AD, contact Airbus SAS, Airworthiness Office—EIAS, Rond-Point Emile Dewoitine No: 2, 31700 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email account.airworth-eas@airbus.com; internet https://www.airbus.com. You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195. It is also available in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA–2022–0389. Examining the AD Docket You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA–2022–0389; 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 AD, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above. FOR FURTHER INFORMATION CONTACT : Dan Rodina, Aerospace Engineer, Large Aircraft Section, FAA, International Validation Branch, 2200 South 216th St., Des Moines, WA 98198; telephone 206–231–3225; email Dan.Rodina@ faa.gov. SUPPLEMENTARY INFORMATION : Comments Invited The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under ADDRESSES . Include ‘‘Docket No. FAA–2022–0389; Project Identifier MCAI–2022–00291–T’’ at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, 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 final rule 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 final rule. 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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Dan Rodina, Aerospace Engineer, Large Aircraft Section, FAA, International Validation Branch, 2200 South 216th St., Des Moines, WA 98198; telephone 206–231– 3225; email Dan.Rodina@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2022–0032, dated March 3, 2022 (EASA AD 2022– 0032) (also referred to as the MCAI), to correct an unsafe condition for all Airbus SAS Model A318–111, –112, –121, and –122 airplanes; Model A319– 111, –112, –113, –114, –115, –131, –132, –133, –151N, –153N, and –171N airplanes; Model A320–211, –212, –214, –215, –216, –231, –232, –233, –251N, –252N, –253N, –271N, –272N, and –273N airplanes; and Model A321–111, –112, –131, –211, –212, –213, –231, –232, –251N, –251NX, –252N, –252NX, –253N, –253NX, –271N, –271NX, –272N, and –272NX airplanes. Model VerDate Sep<11>2014 15:57 Apr 14, 2022 Jkt 256001 PO 00000 Frm 00006 Fmt 4700 Sfmt 4700 E:\FR\FM\15APR1.SGM 15APR1 jspears on DSK121TN23PROD with RULES1

22439 Federal Register / Vol. 87, No. 73 / Friday, April 15, 2022 / Rules and Regulations A320–215 airplanes are not certificated by the FAA and are not included on the U.S. type certificate data sheet; this AD therefore does not include those airplanes in the applicability. This AD was prompted by the detection of several BSCU channel failures on a newly developed BSCU, having part number (P/N) E21327307. In the case of a loss of a single channel, the remaining channel will control aircraft braking. However, in case of dual channel failures, a loss of anti-skid function together with the reversion to the alternate braking mode, and the loss of nose wheel steering on these airplanes, could be induced. The FAA is issuing this AD to address this condition, which, if not corrected, could lead to loss of braking performance with significant increase in airplane stopping distance, possibly resulting in runway excursion. See the MCAI for additional background information. Related Service Information Under 1 CFR Part 51 EASA AD 2022–0032 specifies procedures for replacing BSCUs with P/ N E21327307, on which a fault signature is triggered. EASA AD 2022–0032 also specifies procedures for implementing the instructions of master minimum equipment list (MMEL) updates on the basis of which the operator’s existing MEL must be amended—that is, procedures for revising the operator’s existing FAA-approved MEL with the provisions in the MMEL updates specified in the EASA AD. EASA AD 2022–0032 also limits the installation of affected parts. Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022, defines BSCU fault signatures that may be triggered on the airplane, and specifies procedures for replacing affected parts among other actions. This material 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 These products have been approved by the aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA’s bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI described above. The FAA is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of these same type designs. Requirements of This AD This AD requires accomplishing the actions specified in EASA AD 2022– 0032 described previously, except for any differences identified as exceptions in the regulatory text of this AD. EASA AD 2022–0032 requires operators to ‘‘inform all flight crews’’ of revisions to the MMEL, and thereafter to ‘‘operate the aeroplane accordingly.’’ However, this AD does not specifically require those actions as they are already required by FAA regulations. FAA regulations (14 CFR 121.628(a)(2)) require operators to provide pilots with access to all of the information contained in the operator’s existing MEL. Furthermore, 14 CFR 121.628 (a)(5) requires airplanes to be operated under all applicable conditions and limitations contained in the operator’s existing MEL. Therefore, including a requirement in this AD to operate the airplane according to the revised MEL would be redundant and unnecessary. Further, compliance with such a requirement in an AD would be impracticable to demonstrate or track on an ongoing basis; therefore, a requirement to operate the airplane in such a manner would be unenforceable. Explanation of Required Compliance Information In the FAA’s ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, EASA AD 2022–0032 is incorporated by reference in this AD. This AD requires compliance with EASA AD 2022–0032 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Using common terms that are the same as the heading of a particular section in EASA AD 2022–0032 does not mean that operators need comply only with that section. For example, where the AD requirement refers to ‘‘all required actions and compliance times,’’ compliance with this AD requirement is not limited to the section titled ‘‘Required Action(s) and Compliance Time(s)’’ in EASA AD 2022–0032. Service information required by EASA AD 2022–0032 for compliance will be available at https://www.regulations.gov by searching for and locating Docket No. FAA–2022–0389 after this AD is published. Interim Action The FAA considers this AD interim action. If final action is later identified, the FAA might consider further rulemaking then. FAA’s Justification and Determination of the Effective Date Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq. ) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for ‘‘good cause,’’ finds that those procedures are ‘‘impracticable, unnecessary, or contrary to the public interest.’’ Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause. An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because dual BSCU channel failures can induce loss of anti-skid function together with the reversion to the alternate braking mode, and the loss of nose wheel steering, and lead to loss of braking performance with significant increase in airplane stopping distance, possibly resulting in runway excursion. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b)(3)(B). In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment. Regulatory Flexibility Act (RFA) The requirements of the RFA do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required. Costs of Compliance The FAA estimates that this AD affects 1,500 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: VerDate Sep<11>2014 15:57 Apr 14, 2022 Jkt 256001 PO 00000 Frm 00007 Fmt 4700 Sfmt 4700 E:\FR\FM\15APR1.SGM 15APR1 jspears on DSK121TN23PROD with RULES1

22440 Federal Register / Vol. 87, No. 73 / Friday, April 15, 2022 / Rules and Regulations E STIMATED C OSTS FOR R EQUIRED A CTIONS Labor cost Parts cost Cost per product Cost on U.S. operators Up to 4.5 work-hours × $85 per hour = $382.50 ........................................................ $0 Up to $382.50 ........ Up to $573,750. The FAA has received no definitive data on which to base the cost estimates for the replacement parts specified in this AD. According to the manufacturer, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. The FAA does not control warranty coverage for affected individuals. As a result, the FAA has included all known costs in the cost estimate. 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, and (2) Will not affect intrastate aviation in Alaska. 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 ■ 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] ■ 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2022–07–15 Airbus SAS: Amendment 39– 22003; Docket No. FAA–2022–0389; Project Identifier MCAI–2022–00291–T. (a) Effective Date This airworthiness directive (AD) is effective May 2, 2022. (b) Affected ADs None. (c) Applicability This AD applies to the Airbus SAS airplanes, certificated in any category, identified in paragraphs (c)(1) through (4) of this AD. (1) All Model A318–111, –112, –121, and –122 airplanes. (2) All Model A319–111, –112, –113, –114, –115, –131, –132, –133, –151N, –153N, and –171N airplanes. (3) All Model A320–211, –212, –214, –216, –231, –232, –233, –251N, –252N, –253N, –271N, –272N, and –273N airplanes. (4) All Model A321–111, –112, –131, –211, –212, –213, –231, –232, –251N, –251NX, –252N, –252NX, –253N, –253NX, –271N, –271NX, –272N, and –272NX airplanes. (d) Subject Air Transport Association (ATA) of America Code 32, Landing gear. (e) Unsafe Condition This AD was prompted by the detection of several channel failures on a newly developed braking and steering control unit (BSCU), inducing, in case of dual channel failures, loss of anti-skid function together with the reversion to the alternate braking mode, and the loss of nose wheel steering. The FAA is issuing this AD to address this condition, which could lead to loss of braking performance with significant increase in airplane stopping distance, possibly resulting in runway excursion. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2022–0032, dated March 3, 2022 (EASA AD 2022–0032). (h) Exceptions to EASA AD 2022–0032 (1) Where EASA AD 2022–0032 defines ‘‘the AOT’’ as ‘‘Airbus Alert Operators Transmission (AOT) A32N025–22 [undated],’’ this AD requires using Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022. (2) Where paragraph (1) of EASA AD 2022– 0032 specifies replacement of affected parts, replace the affected part in accordance with the ‘‘Remove and replace BSCU P/N E21327307’’ step in paragraph 5.6., ‘‘Instructions,’’ of Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022. No other actions in Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022, are required for compliance for the replacement. (3) Where EASA AD 2022–0032 refers to its effective date, this AD requires using the effective date of this AD. (4) Where paragraph (2) of EASA AD 2022– 0032 requires operators to ‘‘implement the instructions of the MMEL [master minimum equipment list] update,’’ this AD requires revising the operator’s existing FAA- approved minimum equipment list (MEL) with the provisions specified in ‘‘The MMEL update’’ as identified in EASA AD 2022– 0032. (5) Where paragraph (2) of EASA AD 2022– 0032 specifies to ‘‘inform all flight crews, and, thereafter, operate the aeroplane accordingly,’’ this AD does not require those actions as those actions are already required by existing FAA operating regulations. (6) The ‘‘Remarks’’ section of EASA AD 2022–0032 does not apply to this AD. (i) No Reporting Requirement Although Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022, specifies to report certain information and send affected parts to the manufacturer, this AD does not include those actions. 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22441 Federal Register / Vol. 87, No. 73 / Friday, April 15, 2022 / Rules and Regulations (j) Additional AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, Large Aircraft Section, International Validation 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 responsible Flight Standards Office, as appropriate. If sending information directly to the Large Aircraft Section, International Validation Branch, send it to the attention of the person identified in paragraph (k) of this AD. Information may be emailed to: 9-AVS-AIR- 730-AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, Large Aircraft Section, International Validation Branch, FAA; or EASA; or Airbus SAS’s EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (k) Related Information For more information about this AD, contact Dan Rodina, Aerospace Engineer, Large Aircraft Section, FAA, International Validation Branch, 2200 South 216th St., Des Moines, WA 98198; telephone 206–231– 3225; email Dan.Rodina@faa.gov. (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference 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 this AD specifies otherwise. (i) European Union Aviation Safety Agency (EASA) AD 2022–0032, dated March 3, 2022. (ii) Airbus Alert Operators Transmission A32N025–22, Rev 00, dated February 24, 2022, including Appendixes 1 through 4, dated February 21, 2022. (3) For EASA AD 2022–0032, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may find this EASA AD on the EASA website at https:// ad.easa.europa.eu. For Airbus service information identified in this AD, contact Airbus SAS, Airworthiness Office—EIAS, Rond-Point Emile Dewoitine No: 2, 31700 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email account.airworth-eas@airbus.com; internet https://www.airbus.com. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195. (5) You may view this material 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 March 29, 2022. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2022–08213 Filed 4–13–22; 11:15 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2022–0386; Project Identifier AD–2022–00336–E; Amendment 39–22001; AD 2022–07–13] RIN 2120–AA64 Airworthiness Directives; Pratt & Whitney Division Turbofan Engines AGENCY : Federal Aviation Administration (FAA), DOT. ACTION : Final rule; request for comments. SUMMARY : The FAA is adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090–3 model turbofan engines. This AD was prompted by an in-flight shutdown (IFSD) of an engine due to an air/oil heat exchanger leak caused by corrosion and subsequent investigation by the manufacturer that revealed additional air/oil heat exchanger leaks. This AD requires an inspection of the air/oil heat exchanger and, depending on the results of the inspection, replacement of the air/oil heat exchanger. This AD also provides instructions for storing an air/ oil heat exchanger after inspection. The FAA is issuing this AD to address the unsafe condition on these products. DATES : This AD is effective May 2, 2022. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 2, 2022. The FAA must receive comments on this AD by May 31, 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 final rule, contact Pratt & Whitney Division, 400 Main Street, East Hartford, CT 06118; phone: (860) 565–0140; email: help24@prattwhitney.com; website: https:// connect.prattwhitney.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. It is also available at https:// www.regulations.gov by searching for and locating Docket No. FAA–2022– 0386. Examining the AD Docket You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA–2022–0386; 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 street address for the Docket Operations is listed above. FOR FURTHER INFORMATION CONTACT : Carol Nguyen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238–7655; email: carol.nguyen@ faa.gov . SUPPLEMENTARY INFORMATION : Background On November 9, 2021, a Boeing Model 777 airplane, powered by PW PW4077 engines, on a ferry flight from San Francisco, CA to Honolulu, HI, experienced an oil leak on the number 1 engine that resulted in an IFSD and air turnback to San Francisco, CA. A post- flight inspection revealed that the oil leak was from the air/oil heat exchanger. After this event, on December 19, 2021, the manufacturer was made aware of another oil leak related to the air/oil heat exchanger that was discovered during a post-flight inspection after the first flight out of storage. Subsequent investigation revealed 19 air/oil heat exchanger leaks occurred on the affected engines during the past year, which is significantly higher than the three to four air/oil heat exchanger leaks typically occurring each year. After VerDate Sep<11>2014 15:57 Apr 14, 2022 Jkt 256001 PO 00000 Frm 00009 Fmt 4700 Sfmt 4700 E:\FR\FM\15APR1.SGM 15APR1 jspears on DSK121TN23PROD with RULES1