2022-11550. Airworthiness Directives; Airbus SAS Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (SNPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier proposal to supersede Airworthiness Directive (AD) 2020-18-04, which applies to all Airbus SAS Model A350-941 and -1041 airplanes. This action revises the notice of proposed rulemaking (NPRM) by requiring a modification (replacement of each affected slat power control unit (PCU) with a slat PCU having a different part number), requiring an inspection report, and revising the limitations on the installation of affected parts, as specified in a European Union Aviation Safety Agency (EASA) AD, which is proposed for incorporation by reference. The FAA is proposing this AD to address the unsafe condition on these products. Since these actions would impose an additional burden over those in the NPRM, the FAA is reopening the comment period to allow the public the chance to comment on these changes.

DATES:

The FAA must receive comments on this SNPRM by July 18, 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: [phone].

• 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 that will be incorporated by reference (IBR) in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone [phone]; email [e-mail]; internet www.easa.europa.eu. You may find this material on the EASA website at https://ad.easa.europa.eu. 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-2021-0833.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0833; 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 SNPRM, 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, International Validation Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax [phone]; email [e-mail].

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-2021-0833; Project Identifier MCAI-2021-00245-T” 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 SNPRM.

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 Dan Rodina, Aerospace Engineer, Large Aircraft Section, International Validation Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax [phone]; email [e-mail]. 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 issued AD 2020-18-04, Amendment 39-21225 (85 FR 54896, September 3, 2020) (AD 2020-18-04), which applies to all Airbus SAS Model A350-941 and -1041 airplanes. AD 2020-18-04 requires a one-time health check of the slat PCU torque sensing unit (TSU) for discrepancies, and corrective actions if necessary; a detailed inspection of the left-hand (LH) and right-hand (RH) slat transmission systems for discrepancies, and corrective actions if necessary; and LH and RH track 12 slat gear rotary actuator (SGRA) water drainage and vent plug cleaning (which includes an inspection for moisture).

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD to supersede AD 2020-18-04 that would apply to all Airbus SAS Model A350-941 and -1041 airplanes. The NPRM published in the Federal Register on September 30, 2021 (86 FR 54136) (the NPRM). The NPRM was prompted by a determination that the one-time health check must be repetitive instead to monitor the TSU wear, and that the water drainage and vent plug cleaning is no longer required. The NPRM proposed to require repetitive health checks of the slat PCU TSU, a detailed visual inspection of the slat transmission systems, and corrective actions if necessary.

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, EASA determined that requiring modification of the PCU by replacing each affected slat PCU with a serviceable PCU (one having a different part number) is necessary. EASA issued a new AD to require this modification. In addition, in its new AD, EASA clarified the limitations related to when an affected slat PCU may be installed on an airplane.

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2021-0275, dated December 10, 2021 (EASA AD 2021-0275) (also referred to after this as the MCAI), to correct an unsafe condition for all Airbus SAS Model A350-941 and -1041 airplanes. You may examine the MCAI in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0833.

This proposed AD was prompted by a report of a slat system jam during landing, the determination that health checks must be repetitive to monitor TSU wear, and the development of a modification that terminates the repetitive health checks. The FAA is proposing this AD to address a slat system jam during landing, which could lead to a double shaft disconnection/rupture, potentially causing one or more slat surfaces to be no longer connected to either the slat wing tip brake or the slat PCU, possibly resulting in reduced control of the airplane. See the MCAI for additional background information.

Explanation of Retained Requirements

Although this proposed AD does not explicitly restate the requirements of AD 2020-18-04, this proposed AD would retain certain requirements of AD 2020-18-04. Those requirements are referenced in EASA AD 2021-0275, which, in turn, is referenced in paragraph (g) of this proposed AD.

Related Service Information Under 1 CFR Part 51

EASA AD 2021-0275 specifies procedures for repetitive health checks of the slat PCU TSU for discrepancies, and corrective actions (replacement) if necessary; a detailed visual inspection of the LH and RH slat transmission systems for discrepancies, inspection report, and corrective actions (repair) if necessary; and a modification of the PCU (replacement of each slat PCU having part number (P/N) 4785A0000-04 or 4785A0000-05 with a slat PCU having P/N 4785A0000-06), which terminates the repetitive health checks. EASA AD 2021-0275 also specifies limitations for installing affected slat PCUs. 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.

Comments

The FAA received comments from one commenter, Air Line Pilots Association, International (ALPA), who supported the NPRM without change.

The FAA received additional comments from a commenter, Delta Air Lines (Delta). The following presents the comments received on the NPRM and the FAA's response to each comment.

Request To Refer to Most Recent MCAI

Delta requested that the FAA wait to publish the final rule until EASA releases an updated AD, and then revise paragraph (g) of the proposed AD to reference the new EASA AD instead. Delta noted that EASA planned AD (PAD) 21-157 proposed to supersede EASA AD 2021-0053R1, dated April 19, 2021 (EASA AD 2021-0053R1), which was specified in the NPRM. Delta reasoned that issuing two FAA ADs within a short period of time would create unnecessary paperwork and processing time.

The FAA agrees to reference the new MCAI. As discussed in the Actions Since the NPRM was Issued portion of this SNPRM, EASA has issued EASA AD 2021-0275 to add a modification action, and the FAA has determined that it is necessary to include the new action in the proposed requirements. The FAA has revised this SNPRM to reference EASA AD 2021-0275.

Request To Correct Reference to an Appendix

Delta requested that an exception to paragraph (h) of the proposed AD be provided to correct a reference in paragraph (4) of EASA AD 2021-0053R1. Delta requested that the exception remove reference to “Appendix 5 of the AOT,” which does not exist in Airbus Alert Operators Transmission A27P016-20, Revision 02, dated July 19, 2021, and instead, reference the title of the appendix.

The FAA agrees to revise paragraph (h) of this proposed AD. Paragraph (4) of EASA AD 2021-0275 also references an appendix number instead of the appendix title. The FAA has added paragraph (h)(3) to this proposed AD.

Request To Detail Corrective Actions

Delta requested that the FAA coordinate with Airbus to provide instructions for the complete slat transmission system inspection and corrective action. Delta stated that information should be added to the airplane maintenance manual (AMM) or provided in a technical information letter, and then addressed in the proposed AD with a new exception paragraph. Delta stated that Airbus Alert Operators Transmission A27P016-20, Revision 02, dated July 19, 2021, specifies that if there are any findings, the complete slat transmission system would have to be inspected and any damaged parts replaced. Delta reasoned that since EASA AD 2021-0053R1 states to contact Airbus for corrective action, Airbus might have instructions for the complete slat transmission. Delta noted that providing those instructions in advance would be beneficial to operators because of reduced delays in waiting for instructions.

The FAA disagrees with the request. The FAA notes that Airbus Alert Operators Transmission A27P016-20, Revision 02, dated July 19, 2021, specifies that “it is expected that” the complete slat transmission system would have to be inspected and any damaged parts replaced, not that these actions will be required. The corrective action instructions that would be provided are dependent on the inspection findings and would not be transferrable to other airplanes without further review. The FAA has not changed this proposed AD in this regard.

Request To Revise Paragraph (g) of Proposed AD

Delta requested that paragraph (g) of the proposed AD be revised to include reference to paragraph (i) of the proposed AD in regards to exceptions. Delta stated that if paragraph (g) of the proposed AD does not identify both paragraphs (h) and (i) of the proposed AD as exceptions, there could be confusion if only one exclusionary paragraph is identified in paragraph (g).

The FAA agrees. The FAA has revised paragraph (g) of the proposed AD to add reference to paragraph (i) of the proposed AD.

Request To Remove Calendar Time From Compliance Times

Delta requested the FAA revise the proposed AD to add a new exception removing a calendar-based compliance time to paragraph (h) of the proposed AD. Delta specified a request for removal of the 6-month compliance time specified in table 1 of EASA AD 2021-0053R1. Delta reasoned that the 6-month compliance time is irrelevant to the airworthiness of the airplane and an unnecessary burden to operators because slat PCU failure is associated with operation cycles and the wear-out mode for the TSU is flight cycles.

The FAA disagrees with the request. The operator did not provide data to substantiate its request. EASA, as the State of Design Authority for these airplanes, based on a risk assessment, determined the compliance time provides an acceptable level of safety. In addition, the FAA considered not only the urgency associated with the subject unsafe condition, but also the manufacturer's and EASA's recommendations. After considering all the available information, the FAA determined that the compliance time, as proposed, represents an appropriate interval of time in which the required actions can be performed in a timely manner within the affected fleet, while still maintaining an adequate level of safety. However, under the provisions of paragraph (i) of this proposed AD, the FAA may consider requests for an alternative method of compliance (AMOC) after the publication of the final rule. The FAA has not revised this proposed AD in this regard.

Request To Clarify MCAI Wording in Note 2 of MCAI

Delta requested adding an exception to paragraph (h) of the proposed AD to revise wording in note 2 of EASA AD 2021-0053R1. Delta suggested revising the phrase “certificate of release accompanying the replacement part will clarify” to “. . . may be used to clarify.” Delta stated that it interprets the intention of note 2 of EASA AD 2021-0053R1 is to provide an additional means of calculating the compliance time of the next TSU health check. Delta added that leaving the wording as-is could lead to interpreting note 2 as an AD requirement and mandate that the operator ensure all future certificates of release include this clarifying information.

The FAA agrees with the commenter's request and notes that the same wording exists in EASA AD 2021-0275. The FAA has added paragraph (h)(4) to this proposed AD to provide the requested clarification.

FAA's Determination

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the State of Design Authority, the FAA has been notified of the unsafe condition described in the MCAI and service information referenced above. The FAA is proposing this AD because the FAA evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Certain changes described above expand the scope of the NPRM. As a result, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this SNPRM.

Proposed AD Requirements of This SNPRM

This proposed AD would require accomplishing the actions specified in EASA AD 2021-0275 described previously, except for any differences identified as exceptions in the regulatory text of this proposed AD. This proposed AD would also limit the installation of affected parts under certain conditions. Finally, this proposed AD would require reporting all inspection results to Airbus.

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, the FAA proposes to incorporate EASA AD 2021-0275 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2021-0275 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2021-0275 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 2021-0275. Service information required by EASA AD 2021-0275 for compliance will be available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0833 after the FAA final rule is published.

Interim Action

The preamble to the AD 2020-18-04 explains that the FAA considers those requirements “interim action” and that the manufacturer is developing a final action to address the unsafe condition. That AD explains that the FAA might consider further rulemaking if a final action is identified. The same explanation was in the preamble of the NPRM. Since the FAA issued AD 2020-18-04 and the NPRM, the manufacturer has developed a modification to the PCU, and the FAA has determined that further rulemaking is indeed necessary; this proposed AD follows from that determination.

Costs of Compliance

The FAA estimates that this proposed AD affects 15 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs for Required Actions *

Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Up to 40 work-hours × $85 per hour = $3,400	$275,300	Up to $278,700	Up to $4,180,500.
* Table does not include estimated costs for reporting.

The FAA estimates that it would take about 1 work-hour per product to comply with the proposed reporting requirement in this proposed AD. The average labor rate is $85 per hour. Based on these figures, the FAA estimates the cost of reporting the inspection results on U.S. operators to be up to $1,275, or $85 per product.

The FAA has received no definitive data on which to base the cost estimates for the on-condition repairs specified in this proposed AD.

According to the manufacturer, some or all of the costs of this proposed 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.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to take approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.

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

[Amended]

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive (AD) 2020-18-04, Amendment 39-21225 ( 85 FR 54896, September 3, 2020); and

b. Adding the following new AD:

Airbus SAS: Docket No. FAA-2021-0833; Project Identifier MCAI-2021-00245-T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by July 18, 2022.

(b) Affected ADs

This AD replaces AD 2020-18-04, Amendment 39-21225 (85 FR 54896, September 3, 2020) (AD 2020-18-04).

(c) Applicability

This AD applies to all Airbus SAS Model A350-941 and -1041 airplanes, certificated in any category.

(d) Subject

Air Transport Association (ATA) of America Code 27, Flight Controls.

(e) Reason

This AD was prompted by a report of a slat system jam during landing, the determination that health checks must be repetitive to monitor torque sensor unit (TSU) wear, and the development of a modification that terminates the repetitive health checks. The FAA is issuing this AD to address a slat system jam during landing, which could lead to a double shaft disconnection/rupture, potentially causing one or more slat surfaces to be no longer connected to either the slat wing tip brake or the slat power control unit (PCU), possibly resulting in reduced control of the airplane.

(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 2021-0275, dated December 10, 2021 (EASA AD 2021-0275).

(h) Exceptions to EASA AD 2021-0275

(1) Where EASA AD 2021-0275 refers to March 11, 2021 (the effective date of EASA AD 2021-0053, dated February 25, 2021), this AD requires using the effective date of this AD.

(2) Where paragraph (2) of EASA AD 2021-0275 specifies compliance times for accomplishment of certain actions, replace the text “but not exceeding the compliance time for the repeat health check as determined in accordance with the instructions of AOT [Alert Operators Transmission] A27P015-20, or AOT A27P016-20,” with “but within the applicable compliance time specified in paragraph 4.2.3.1 of AOT A27P015-20; or 4.2.2.2.2 or 4.2.2.3.2 of AOT A27P016-20; as applicable.”

(3) Where paragraph (4) of EASA AD 2021-0275 specifies “Appendix 5 of the AOT,” use “the Appendix labeled TSU Condition Check Flowchart of the AOT.”

(4) Where note 2 of EASA AD 2021-0275 states that the certificate of release accompanying a replacement part “will clarify,” use “may be used to clarify.”

(5) The “Remarks” section of EASA AD 2021-0275 does not apply to this AD.

(6) Where EASA AD 2021-0275 refers to its effective date, this AD requires using the effective date of this AD.

(7) Where any service information referenced in EASA AD 2021-0275 specifies reporting, this AD requires only reporting of damage findings at the applicable time specified in paragraph (h)(7)(i) or (ii) of this AD. If operators have reported findings as part of obtaining any corrective actions approved by Airbus SAS's EASA Design Organization Approval (DOA), operators are not required to report those findings as specified in this paragraph.

(i) If the inspection was done on or after the effective date of this AD: Submit the report within 30 days after the inspection.

(ii) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

(i) Additional FAA 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 (j)(2) of this AD. Information may be emailed to: [e-mail]. 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.

(3) Required for Compliance (RC): Except as required by paragraph (i)(2) of this AD, if any service information referenced in EASA AD 2021-0275 contains paragraphs that are labeled as RC, the instructions in RC paragraphs, including subparagraphs under an RC paragraph, must be done to comply with this AD; any paragraphs, including subparagraphs under those paragraphs, that are not identified as RC are recommended. The instructions in paragraphs, including subparagraphs under those paragraphs, not identified as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the instructions identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to instructions identified as RC require approval of an AMOC.

(j) Related Information

(1) For EASA AD 2021-0275, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone [phone]; email [e-mail]; internet www.easa.europa.eu. You may find this EASA AD on the EASA website at https://ad.easa.europa.eu. 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. This material may be found in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0833.

(2) For more information about this AD, contact Dan Rodina, Aerospace Engineer, Large Aircraft Section, International Validation Branch, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone and fax [phone]; email [e-mail].

Issued on May 24, 2022.

Gaetano A. Sciortino,

Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.