2023-11064. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2020–26–08 which applies to The Boeing Company Model 787–8, 787–9, and 787–10 airplanes powered by Rolls-Royce Trent 1000 engines. AD 2020–26–08 requires repetitive inspections of the inner fixed structure (IFS) forward upper fire seal and thermal insulation blankets in the forward upper area of the thrust reverser (TR) for damage and applicable on-condition actions. Since the FAA issued AD 2020–26–08, it was determined a new upper splitter fairing assembly is needed to prevent the damage to the fire seal and thermal insulation blanket. This proposed AD would continue to require the actions specified in AD 2020–26–08 and would require determining if an affected part number of the upper splitter fairing assembly is installed on the engine, replacing an affected upper splitter fairing assembly part number with a new upper splitter fairing assembly part number, inspecting the IFS forward upper fire seal and thermal insulation blanket for any damage, and applicable on-condition actions. This proposed AD would also prohibit the installation of affected parts. 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 10, 2023.

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 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA–2023–1037; 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.

Material Incorporated by Reference:

• For service information identified in this NPRM, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Boulevard, MC 110–SK57, Seal Beach, CA 90740–5600; telephone [phone]; website: myboeingfleet.com.

• You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th Street, Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195. It is also available at regulations.gov by searching for and locating Docket No. FAA–2023–1037.

FOR FURTHER INFORMATION CONTACT:

Tak Kobayashi, Aerospace Engineer, Propulsion Section, West Certification Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712–4137; telephone: [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–2023–1037; Project Identifier AD–2023–00511–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 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 Tak Kobayashi, Aerospace Engineer, Propulsion Section, West Certification Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712–4137; telephone: [phone]; email: [e-mail]. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA issued AD 2020–26–08, Amendment 39–21363 (85 FR 83755, December 23, 2020) (AD 2020–26–08), for The Boeing Company Model 787–8, 787–9, and 787–10 airplanes powered by Rolls-Royce Trent 1000 engines. AD 2020–26–08 was prompted by reports of damage to the IFS forward upper fire seal and damage to the thermal insulation blankets in the forward upper area of the thrust reverser. AD 2020–26–08 requires repetitive inspections of the IFS forward upper fire seal and thermal insulation blankets in the forward upper area of the TR for damage and applicable on-condition actions. The FAA issued AD 2020–26–08 to address the damage to the IFS forward upper fire seal and the thermal insulation blankets of the TR due to airflow through structural gapping that could occur at the interface between the leading edge of the IFS and the engine splitter structure during flight. Failure of the IFS forward upper fire seal could cause the loss of seal pressurization and degrade the ability to detect and extinguish an engine fire, resulting in an uncontrolled fire. Damage to the TR insulation blanket could result in thermal damage to the TR inner wall, the subsequent release of engine exhaust components, and consequent damage to critical areas of the airplane. Furthermore, damage to the TR inner wall and IFS forward upper fire seal could compromise the integrity of the firewall and its ability to contain an engine fire, resulting in an uncontrolled fire, which could lead to loss of airplane control.

Actions Since AD 2020–26–08 Was Issued

The preamble to AD 2020–26–08 specifies that the FAA considers that AD “interim action” and that the FAA might consider further rulemaking if a modification is developed, approved, and available. The manufacturer has since developed such a modification (installation of upper splitter fairing assembly part number KH99185), which would terminate the repetitive inspections required by AD 2020–26–08. The FAA has determined that this modification should be required.

AD 2020–26–08 specifies doing actions in accordance with Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020. Boeing has since issued Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021. Issue 002 adds two variable numbers to the effectivity that were missing in Issue 001; however, Issue 002 does not change the procedures in the Accomplishment Instructions or the compliance times. The FAA has added Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021, as an optional method of compliance to paragraph (g) of this proposed AD.

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 Under 1 CFR Part 51

The FAA reviewed Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022. This service information specifies procedures for replacing the upper splitter fairing assembly with a new upper splitter fairing assembly with ramp fairing incorporated, doing a general visual inspection of the IFS forward upper fire seal and thermal insulation blanket of the left and right TR halves for any damage, and applicable on-condition actions. On-condition actions include replacing the IFS forward upper fire seal and thermal insulation blanket of each TR half if damage is found. Those procedures in the service information apply to each affected engine.

The FAA also reviewed Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021. The service information describes procedures for repetitive inspections of the IFS forward upper fire seal and thermal insulation blanket of the left and right TR halves for any damage, and applicable on-condition actions. On-condition actions include replacing the IFS forward upper fire seal and thermal insulation blanket of each TR half if damage is found. Those procedures in the service information apply to each affected engine.

This proposed AD would also require Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020, which the Director of the Federal Register approved for incorporation by reference as of January 27, 2021 (85 FR 83755, December 23, 2020).

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 section.

Proposed AD Requirements in This NPRM

This proposed AD would retain all requirements of AD 2020–26–08. Accomplishing the new actions proposed in this AD would terminate the requirements of AD 2020–26–08.

This proposed AD would require accomplishing the actions specified in the service information already described, except as discussed under “Differences Between this Proposed AD and the Service Information” and except for any differences identified as exceptions in the regulatory text of this proposed AD. This proposed AD would also prohibit the installation of affected parts. For information on the procedures and compliance times, see this service information at regulations.gov under Docket No. FAA–2023–1037.

Differences Between This Proposed AD and the Service Information

The effectivity of Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022, is limited to Model 787–8, –9 and –10 airplanes having certain line numbers. However, the applicability of this proposed AD includes all Boeing Model 787–7, –8, and –9 airplanes with Rolls-Royce Trent 1000 engines installed. Because the affected upper splitter fairing assembly are rotable parts, the FAA has determined that these parts could later be installed on airplanes that were initially delivered with acceptable upper splitter fairing assembly, thereby subjecting those airplanes to the unsafe condition. The FAA has determined that the Accomplishment Instructions in Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022, can be applied to airplanes outside the effectivity of the service information if an affected part is installed on those airplanes. This proposed AD includes an inspection or records review to determine if an affected part is installed.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 13 airplanes of U.S. registry. 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. operators
Inspection (retained actions from AD 2020–26–08)	2 work-hours × $85 per hour = $170 per inspection cycle	$0	$170 per inspection cycle	$2,210 per inspection cycle.
Inspection or records review (new proposed action)	1 work-hour × $85 per hour = $85	0	$85	$1,105.
Replacement of each upper splitter fairing assembly (new proposed action)	71 work-hours × $85 per hour = $6,035	230,000	$236,035	$3,068,455.
Inspection (new proposed action)	2 work-hours × $85 per hour = $170	0	$170	$2,210.

The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the proposed inspection. The agency has no way of determining the number of aircraft that might need these replacements:

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Fire seal replacement	2 work-hours × $85 per hour = $170 per TR half	$1,383 per TR half	$1,553 per TR half (4 TR halves per airplane).
Thermal insulation blanket replacement	1 work-hour × $85 per hour = $85 per TR half	$18,214 per TR half	$18,299 per TR half.

According to the manufacturer, some of the costs of this AD may be covered under warranty by Goodrich, thereby reducing the cost impact on affected operators. The FAA does not control warranty coverage for affected operators. 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

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 2020–26–08, Amendment 39–21363 ( 85 FR 83755, December 23, 2020), and

b. Adding the following new Airworthiness Directive:

The Boeing Company: Docket No. FAA–2023–1037; Project Identifier AD–2023–00511–T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by July 10, 2023.

(b) Affected ADs

This AD replaces AD 2020–26–08, Amendment 39–21363 (85 FR 83755, December 23, 2020) (AD 2020–26–08).

(c) Applicability

This AD applies to The Boeing Company Model 787–8, 787–9, and 787–10 airplanes, certificated in any category, with Rolls-Royce Trent 1000 engines installed.

(d) Subject

Air Transport Association (ATA) of America Code: 72, Turbine/turboprop engine.

(e) Unsafe Condition

This AD was prompted by reports of Rolls-Royce Trent 1000 powered airplanes having damage to the thrust reverser inner fixed structure (IFS) forward upper fire seal and damage to thermal insulation blankets in the forward upper area of the thrust reverser (TR). The FAA is issuing this AD to address the damage to the IFS forward upper fire seal and the thermal insulation blankets of the TR due to airflow through structural gapping that could occur at the interface between the leading edge of the IFS and the engine splitter structure during flight. Failure of the IFS forward upper fire seal could cause the loss of seal pressurization and degrade the ability to detect and extinguish an engine fire, resulting in an uncontrolled fire. Damage to the TR insulation blanket could result in thermal damage to the TR inner wall, the subsequent release of engine exhaust components, and consequent damage to critical areas of the airplane. Furthermore, damage to the TR inner wall and IFS forward upper fire seal could compromise the integrity of the firewall and its ability to contain an engine fire, resulting in an uncontrolled fire.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Retained Actions, With New Service Information and Revised Affected Airplanes

This paragraph restates the requirements of paragraph (g) of AD 2020–26–08, with new service information and revised affected airplanes. For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before the effective date of this AD and for airplanes listed in Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022: Except as specified by paragraph (h) of this AD, at the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020; or Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021; do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020; or Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021. Accomplishing the actions required by paragraph (i)(2) of this AD terminates the actions required by this paragraph.

Note 1 to paragraph (g): Guidance for accomplishing the actions required by paragraph (g) of this AD can be found in Boeing Alert Service Bulletin B787–81205–SB780041–00, Issue 001, dated March 31, 2020, which is referred to in Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020; or in Boeing Alert Service Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021, which is referred to in Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021.

(h) Retained Exceptions to Service Information Specifications in Paragraph (g) of This AD, With Added Reference to New Service Information

This paragraph restates the exceptions specified in paragraph (h) of AD 2020–26–08, with added reference to new service information. Where Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020; or Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021; uses the phrase “the Issue 001 date of Requirements Bulletin B787–81205–SB780041–00 RB,” this AD requires using January 27, 2021, (the effective date of AD 2020–26–08).

(i) New Required Actions

(1) For airplanes with original airworthiness certificate or original export certificate of airworthiness issued on or before the effective date of this AD and for airplanes listed in the Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022: Within 7 years after the effective date of this AD, or within 7 years after the date of issuance of the original airworthiness certificate or original export certificate of airworthiness, whichever occurs later, inspect to determine the part number of the upper splitter fairing assembly installed on each engine. A review of airplane maintenance records is acceptable in lieu of this inspection if the part number of the upper splitter fairing assembly can be conclusively determined from that review. For engines on which no upper splitter fairing assembly part number (P/N) KH60375 was found during the inspection, the actions required by paragraph (g) of this AD are no longer required for that engine.

(2) If, during any inspection or records review required by paragraph (i)(1) of this AD, an upper splitter fairing assembly P/N KH60375 is found on any engine of an airplane: Except as specified by paragraph (j) of this AD, at the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022, for each affected engine. Accomplishing the actions required by this paragraph on all affected engines of an airplane terminates the actions required by paragraph (g) of this AD for that airplane.

Note 2 to paragraph (i)(2): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin B787–81205–SB720007–00, Issue 001, dated December 12, 2022, which is referred to in Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022.

(j) Exceptions to Service Information Specifications for Paragraph (i)(2) of This AD

Where the “Effectivity” paragraph and the Condition and Compliance Time columns of the tables in the “Compliance” paragraph of Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022, use the phrase “the original issue date of Requirements Bulletin B787–81205–SB720007–00 RB,” this AD requires using “the effective date of this AD.”

(k) Parts Installation Prohibition

(1) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued after the effective date of this AD, except for airplanes listed in Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022: As of the effective date of this AD, no person may install an engine with an upper splitter fairing assembly P/N KH60375 on any airplane.

(2) For airplanes with original airworthiness certificate or original export certificate of airworthiness issued on or before the effective date of this AD and for airplanes listed in Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022: At the applicable time specified in paragraph (k)(2)(i) or (ii) of this AD, no person may install an engine with an upper splitter fairing assembly P/N KH60375 on any airplane.

(i) For airplanes on which no upper splitter fairing assembly P/N KH60375 was found during the inspection required by paragraph (i)(1) of this AD: After accomplishing the inspection required by paragraph (i)(1) of this AD.

(ii) For airplanes on which an upper splitter fairing assembly P/N KH60375 was found during the inspection required by paragraph (i)(1) of this AD: At the applicable time specified in paragraph (k)(2)(ii)(A) or (B) of this AD.

(A) For an engine on which an upper splitter fairing assembly P/N KH60375 was not found: After accomplishing the inspection required by paragraph (i)(1) of this AD.

(B) For an engine on which an upper splitter fairing assembly P/N KH60375 was found: After replacing an affected upper splitter fairing assembly part number with a new upper splitter fairing assembly part number for that engine as required by paragraph (i)(2) of this AD.

(l) Alternative Methods of Compliance (AMOCs)

(1) The Manager, AIR–520 Continued Operational Safety 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 manager of the certification office, send it to the attention of the person identified in paragraph (m) of this AD. Information may be emailed to: [e-mail].

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.

(3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization (ODA) that has been authorized by the Manager, AIR–520 Continued Operational Safety Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(m) Related Information

For more information about this AD, contact Tak Kobayashi, Aerospace Engineer, Propulsion Section, West Certification Branch, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712–4137; telephone: [phone]; email: [e-mail].

(n) 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.

(3) The following service information was approved for IBR on [DATE 35 DAYS AFTER PUBLICATION OF THE FINAL RULE].

(i) Boeing Alert Requirements Bulletin B787–81205–SB720007–00 RB, Issue 001, dated December 12, 2022.

(ii) Boeing Alert Requirements Bulletin B787–81205–SB780041–00, Issue 002, dated December 21, 2021.

(4) The following service information was approved for IBR on January 27, 2021 (85 FR 83755, December 23, 2020).

(i) Boeing Alert Requirements Bulletin B787–81205–SB780041–00 RB, Issue 001, dated March 31, 2020.

(ii) [Reserved]

(5) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Boulevard, MC 110–SK57, Seal Beach, CA 90740–5600; telephone [phone]; website: myboeingfleet.com.

(6) You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th Street, Des Moines, WA. For information on the availability of this material at the FAA, call 206–231–3195.

(7) 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, [e-mail], or go to: www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued on May 8, 2023.

Gaetano A. Sciortino,

Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.