2023-23516. Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2021–20–13, which applies to certain Bombardier, Inc., Model CL–600–2B16 (604 Variant) airplanes. AD 2021–20–13 requires repetitive lubrication and repetitive detailed visual inspections (DVI) and non-destructive test (NDT) inspections of the main landing gear (MLG) shock strut lower pins, and replacement if necessary. Since the FAA issued AD 2021–20–13, Bombardier, Inc. developed a new design solution for this potential failure. This proposed AD would continue to require the lubrication and inspections specified in AD 2021–20–13 until the MLG shock strut assembly is modified by replacing the trailing arm bushing and installing new dynamic joint components. 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 December 11, 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–2023–2001; 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, the mandatory continuing airworthiness information (MCAI), 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 Bombardier, Inc., 200 Côte-Vertu Road West, Dorval, Québec H4S 2A3, Canada; North America toll-free telephone [phone] or direct-dial telephone [phone]; email [e-mail]; website bombardier.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.

FOR FURTHER INFORMATION CONTACT:

Gabriel Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 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–2023–2001; Project Identifier MCAI–2023–00666–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 the 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 Gabriel Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone [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 2021–20–13, Amendment 39–21751 (86 FR 57033, October 14, 2021) (AD 2021–20–13), for certain Bombardier, Inc., CL–600–2B16 (604 Variant) airplanes. AD 2021–20–13 was prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued AD CF–2020–54R1, dated December 23, 2020 (Transport Canada AD CF–2020–54R1), to correct an unsafe condition identified as cracking of the MLG shock strut lower pin part number 19146–3. Transport Canada AD CF–2020–54R1 states that friction torque, when the shock strut is under compression loading, causes the pin anti-rotation tangs to become loaded beyond their load carrying capability. According to Transport Canada, this overload condition can result in pin fracture originating at the base of the pin anti-rotation tang and is aggravated by inadequate lubrication.

AD 2021–20–13 requires repetitively lubricating, repetitively inspecting (DVI and NDT inspections for cracking and damage, including fracture of the MLG shock strut lower pin at the pin rotation tang location), and replacing the MLG shock strut lower pin if there is any cracking or damage as a result of the inspections. The FAA issued AD 2021–20–13 to address cracking of the MLG shock strut lower pin. If not addressed, this condition could result in structural failure of one or both MLG.

Actions Since AD 2021–20–13 Was Issued

Since the FAA issued AD 2021–20–13, Transport Canada superseded Transport Canada AD CF–2020–54R1 and issued Transport Canada AD CF–2023–32, dated May 9, 2023 (referred to after this as “the MCAI”). The MCAI states there is a new design solution for this potential failure of the shock strut lower pin, which involves replacing the training arm bushings at the attachment and reassembly of the MLG shock strut assembly to training arm assembly joint with new dynamic joint components. As a result, the MCAI requires this new design as terminating action for the requirements of Transport Canada AD CF–2020–54R1.

Bombardier, Inc. also reduced the range of one group of applicable aircraft from serial numbers 6050 through 6999 to 6050 through 6188. Bombardier, Inc. advises that subsequent aircraft are scheduled to have the new design completed in production. Therefore, the FAA has revised the applicability of this proposed AD accordingly.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA–2023–2001.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bombardier, Inc., service information:

• Service Bulletin 604–32–031, dated December 29, 2022.
• Service Bulletin 605–32–008, dated December 29, 2022.
• Service Bulletin 650–32–005, dated December 29, 2022.

This service information contains procedures for disassembling the left- and right-hand MLG shock strut and trailing arm joint, replacing the trailing arm bushings at the attachment, and re-assembling the joint with new dynamic joint components. These documents are distinct since they apply to different airplane configurations.

This proposed AD would also require the following Bombardier, Inc., service information, which the Director of the Federal Register approved for incorporation by reference as of November 18, 2021 (86 FR 57033, October 14, 2021):

• Service Bulletin 604–32–030, dated June 30, 2020.
• Service Bulletin 605–32–007, dated June 30, 2020.
• Service Bulletin 650–32–004, dated June 30, 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 the ADDRESSES section.

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 this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI and service information referenced above. The FAA is issuing this NPRM after determining that unsafe condition described previously is likely to exist or develop on other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would retain all of the requirements of AD 2021–20–13 until the MLG shock strut assembly to trailing arm assembly joint is modified by accomplishing the actions specified in the service information described previously.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 433 airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs for Required Actions

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Lubrication and inspections (retained actions from AD 2021–20–13)	7 work-hours × $85 per hour = $595	$0	$595 per cycle	$257,635 per cycle.
Modification and testing (new proposed actions)	9 work-hours × $85 per hour = $765	2,435	3,200	1,385,600.

The FAA estimates the following costs to do any necessary on-condition replacement that would be required based on the results of the repetitive inspections. The FAA has no way of determining the number of aircraft that might need this on-condition action:

Estimated Costs of On-Condition Replacement

Labor cost	Parts cost	Cost per product
6 work-hours × $85 per hour = $510	$2,435	$2,945

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 has 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) Will not affect intrastate aviation in Alaska, and

(3) Will 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 2021–20–13, Amendment 39–21751 ( 86 FR 57033, October 14, 2021); and

b. Adding the following new Airworthiness Directive:

Bombardier, Inc.: Docket No. FAA–2023–2001; Project Identifier MCAI–2023–00666–T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by December 11, 2023.

(b) Affected ADs

This AD replaces AD 2021–20–13, Amendment 39–21751 (86 FR 57033, October 14, 2021) (AD 2021–20–13).

(c) Applicability

This AD applies to Bombardier, Inc., Model CL–600–2B16 (604 Variant) airplanes, serial numbers (S/N) 5301 through 5665 inclusive, 5701 through 5988 inclusive, and 6050 through 6188 inclusive, certificated in any category.

(d) Subject

Air Transport Association (ATA) of America Code: 32, Landing gear.

(e) Reason

This AD was prompted by reports of cracking of the main landing gear (MLG) shock strut lower pin. The FAA is issuing this AD to address cracking of the MLG shock strut lower pin. The unsafe condition, if not addressed, could result in structural failure of one or both MLG.

(f) Compliance

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

(g) Retained Repetitive Lubrication, With Revised Applicability

This paragraph restates the requirements of paragraph (g) of AD 2021–20–13, with revised applicability. Within 200 flight hours (FH) or 12 months after November 18, 2021 (the effective date of AD 2021–20–13), whichever occurs first, lubricate the left-hand (LH) and right-hand (RH) MLG shock strut lower pins having part number (P/N) 19146–3, in accordance with paragraph 2.B., “Part A,” of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (g)(1) through (3) of this AD. Repeat thereafter at intervals not to exceed 200 FH or 12 months, whichever occurs first.

(1) For airplanes having S/N 5301 through 5665 inclusive: Bombardier Service Bulletin 604–32–030, dated June 30, 2020.

(2) For airplanes having S/N 5701 through 5988 inclusive: Bombardier Service Bulletin 605–32–007, dated June 30, 2020.

(3) For airplanes having S/N 6050 through 6188 inclusive: Bombardier Service Bulletin 650–32–004, dated June 30, 2020.

(h) Retained Detailed Visual Inspections (DVI), With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2021–20–13, with no changes. At the applicable compliance time specified in paragraphs (h)(1) through (3) of this AD, perform the DVI for cracking and damage of the LH and RH MLG shock strut lower pins having part number (P/N) 19146–3, in accordance with paragraph 2.C., “Part B,” of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (g)(1) through (3) of this AD. Repeat thereafter at intervals not to exceed 400 FH or 24 months, whichever occurs first. If the DVI coincides with a non-destructive testing (NDT) inspection required by paragraph (i) of this AD, the NDT inspection supersedes the DVI for that interval only. If the accumulated flight cycles (FC) of the MLG shock strut lower pin are not known, use the related MLG assembly accumulated FC to determine when to accomplish the actions required by this paragraph.

(1) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before November 18, 2021 (the effective date of AD 2021–20–13) and on which an MLG shock strut lower pin has accumulated fewer than 600 total FC on the pin as of November 18, 2021: Before the accumulation of 750 total FC on the pin.

(2) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before November 18, 2021 (the effective date of AD 2021–20–13) and on which an MLG shock strut lower pin has accumulated 600 total FC or more on the pin as of November 18, 2021: Within 150 FC after November 18, 2021.

(3) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued after November 18, 2021 (the effective date of AD 2021–20–13): Before the accumulation of 750 total FC.

(i) Retained NDT Inspection, With No Changes

This paragraph restates the requirements of paragraph (i) of AD 2021–20–13, with no changes. At the applicable compliance time specified in paragraphs (i)(1) through (4) of this AD: Perform the NDT inspection for cracking and damage of the LH and RH MLG shock strut lower pins having P/N 19146–3, in accordance with paragraph 2.D., “Part C,” of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (g)(1) through (3) of this AD. Repeat thereafter at intervals not to exceed 900 FC. If the accumulated FC of the MLG shock strut lower pin is not known, use the related MLG assembly accumulated FC to determine when to accomplish the actions required by this paragraph.

(1) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before November 18, 2021 (the effective date of AD 2021–20–13) and on which an MLG shock strut lower pin has accumulated fewer than 1,200 total FC on the pin as of November 18, 2021: Before the accumulation of 1,500 total FC on the pin.

(2) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before November 18, 2021 (the effective date of AD 2021–20–13) and on which an MLG shock strut lower pin has accumulated 1,200 total FC or more but fewer than 2,000 total FC on the pin as of November 18, 2021: Within 300 FC after November 18, 2021, or before the accumulation of 2,200 total FC on the pin, whichever occurs first.

(3) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued on or before November 18, 2021 (the effective date of AD 2021–20–13) and on which an MLG shock strut lower pin that has accumulated 2,000 total FC or more on the pin as of November 18, 2021: Within 200 FC after November 18, 2021.

(4) For airplanes with an original airworthiness certificate or original export certificate of airworthiness issued after November 18, 2021 (the effective date of AD 2021–20–13): Before the accumulation of 1,500 total FC.

(j) Retained Replacement, With No Changes

This paragraph restates the requirements of paragraph (j) of AD 2021–20–13, with no changes. If, during any inspection required by this AD, any crack or damage of the MLG shock strut lower pin is detected, before further flight, replace the affected MLG shock strut lower pin with a new part in accordance with paragraph 2.E., “Part D,” of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (g)(1) through (3) of this AD.

(k) New Requirement of This AD: Modification

Within 60 months from the effective date of this AD, modify the LH and RH MLG assembly in accordance with paragraph 2.B. of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (k)(1) through (3) of this AD.

(1) For airplanes having S/N 5301 through 5665 inclusive: Bombardier Service Bulletin 604–32–031, dated December 29, 2022.

(2) For airplanes having S/N 5701 through 5988 inclusive: Bombardier Service Bulletin 605–32–008, dated December 29, 2022.

(3) For airplanes having S/N 6050 through 6188 inclusive: Bombardier Service Bulletin 650–32–005, dated December 29, 2022.

(l) New Requirement of the AD: Testing

Before further flight after completing paragraph (k) of this AD, perform the testing of the MLG shock strut assembly to trailing arm assembly joint in accordance with paragraph 2.C. of the Accomplishment Instructions of the applicable service bulletin, as specified in paragraphs (k)(1) through (3) of this AD.

(m) Terminating Action

Modifying and testing an airplane as required by paragraphs (k) and (l) of this AD terminates the initial and repetitive lubrication and inspections required by paragraphs (g), (h), and (i) of this AD for that airplane.

(n) Additional AD Provisions

(1) Alternative Methods of Compliance (AMOCs): The Manager, 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 manager of the International Validation Branch, mail it to the address identified in paragraph (o)(2) of this AD or email to: [e-mail]. If mailing information, also submit information by email. 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, International Validation Branch, FAA; or Transport Canada; or Bombardier, Inc.'s Transport Canada Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.

(o) Additional Information

(1) Refer to Transport Canada AD CF–2023–32, dated May 9, 2023, for related information. This Transport Canada AD may be found in the AD docket at regulations.gov under Docket No. FAA–2023–2001.

(2) For more information about this AD, contact Gabriel Kim, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone [phone]; email [e-mail].

(p) 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 this AD specifies otherwise.

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

(i) Bombardier Service Bulletin 604–32–031, dated December 29, 2022.

(ii) Bombardier Service Bulletin 605–32–008, dated December 29, 2022.

(iii) Bombardier Service Bulletin 650–32–005, dated December 29, 2022.

(4) The following service information was approved for IBR on November 18, 2021 (86 FR 57033, October 14, 2021).

(i) Bombardier Service Bulletin 604–32–030, dated June 30, 2020.

(ii) Bombardier Service Bulletin 605–32–007, dated June 30, 2020.

(iii) Bombardier Service Bulletin 650–32–004, dated June 30, 2020.

(5) For service information identified in this AD, contact Bombardier, Inc., 200 Côte-Vertu Road West, Dorval, Québec H4S 2A3, Canada; North America toll-free telephone [phone] or direct-dial telephone [phone]; email [e-mail]; website bombardier.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 material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/​federal-register/​cfr/​ibr-locations or email [e-mail].

Issued on October 19, 2023.

Ross Landes,

Deputy Director for Regulatory Operations, Compliance & Airworthiness Division, Aircraft Certification Service.