2024-05963. Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2021–25–12 and AD 2022–11–11, which apply to certain De Havilland Aircraft of Canada Limited Model DHC–8–401 and –402 airplanes. AD 2021–25–12 requires repetitive lubrications of the trailing arm of the nose landing gear (NLG). AD 2021–25–12 also requires revising the existing maintenance or inspection program to include new and revised airworthiness limitations. AD 2022–11–11 requires a modification to the NLG shock strut assembly. Since the FAA issued AD 2021–25–12 and AD 2022–11–11, it has been determined that the pivot pin and tow fitting assembly of the NLG must be replaced. This proposed AD would continue to require the actions specified in AD 2021–25–12 and AD 2022–11–11 and would require replacement of the pivot pin and tow fitting assembly with a new, improved pivot pin and tow fitting assembly and 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 May 6, 2024.

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–2024–0756; 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 De Havilland Aircraft of Canada Limited, Dash 8 Series Customer Response Centre, 5800 Explorer Drive, Mississauga, Ontario, L4W 5K9, Canada; telephone North America (toll-free): 855–310–1013, Direct: 647–277–5820; email [e-mail]; website dehavilland.com.

• You may view this service information 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.

FOR FURTHER INFORMATION CONTACT:

Deep Gaurav, 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–2024–0756; Project Identifier MCAI–2023–00549–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 Deep Gaurav, 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 2021–25–12, Amendment 39–21856 (86 FR 72174, December 21, 2021) (AD 2021–25–12); and AD 2022–11–11, Amendment 39–22061 (87 FR 33627, June 3, 2022) (AD 2022–11–11), for certain DeHavilland Aircraft of Canada Limited Model DHC–8–401 and –402 airplanes. AD 2021–25–12 and AD 2022–11–11 were prompted by an MCAI originated by Transport Canada, which is the aviation authority for Canada. Transport Canada issued AD CF–2009–29R4, dated October 1, 2021 (Transport Canada AD CF–2009–29R4), to correct an unsafe condition.

AD 2021–25–12 requires repetitive lubrications of the trailing arm of the NLG. AD 2021–25–12 also requires revising the existing maintenance or inspection program to include new and revised airworthiness limitations (life limits for certain bolts). AD 2022–11–11 requires modification to the NLG shock strut assembly. The FAA issued AD 2021–25–12 and AD 2022–11–11 to address failure of the pivot pin retention bolt, which could result in a loss of directional control or loss of an NLG tire during takeoff or landing, which could lead to runway excursions.

Actions Since AD 2021–25–12 and AD 2022–11–11 Were Issued

Since the FAA issued AD 2021–25–12 and AD 2022–11–11, Transport Canada superseded AD CF–2009–29R4, and issued Transport Canada AD CF–2023–22, dated March 30, 2023 (Transport Canada AD CF–2023–22) (referred to after this as the MCAI), to correct an unsafe condition on certain DeHavilland Aircraft of Canada Limited Model DHC–8–401 and –402 airplanes. The MCAI states that it requires the removal of pivot pin part number (P/N) 47127–1 or P/N 47127–3 and tow fitting assembly P/N 47160–1, and their replacement with pivot pin P/N 47127–5 and tow fitting assembly P/N 47160–3, as terminating action to the requirements of AD CF–2009–29R4. The pivot pin P/N 47127–5 is now attached directly to the new tow fitting lug and no longer requires the use of a retention bolt. Transport Canada AD CF–2023–22 also prohibits the installation of certain parts. This proposed AD would also remove airplanes from the applicability of AD 2021–25–12 and AD 2022–11–11. The FAA is proposing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA–2024–0756.

Related Service Information Under 1 CFR Part 51

The FAA reviewed De Havilland Aircraft of Canada Limited Service Bulletin 84–32–173, dated November 15, 2022, including Collins Aerospace Service Bulletin 47100–32–153, dated November 10, 2022. This service information specifies procedures for replacing the pivot pin retention mechanism and tow fitting assembly with a new, improved pivot pin and tow fitting assembly, which consists of removing pivot pin linkage components and replacing pivot pin P/N 47127–1 or P/N 47127–3 and tow fitting assembly P/N 47160–1 with pivot pin P/N 47127–5 and tow fitting assembly P/N 47160–3.

This proposed AD would also require De Havilland Aircraft of Canada Limited Service Bulletin 84–32–161, Revision B, dated March 31, 2021, including UTC Aerospace Systems Service Bulletin 47100–32–145, Revision 3, dated March 26, 2021, which the Director of the Federal Register approved for incorporation by reference as of July 8, 2022 (87 FR 33627, June 3, 2022).

This proposed AD would also require De Havilland Aircraft of Canada Limited Service Bulletin 84–32–167, dated August 12, 2021; and De Havilland Aircraft of Canada Limited Temporary Revision ALI–0223, dated October 15, 2020, which the Director of the Federal Register approved for incorporation by reference as of January 5, 2022 (86 FR 72174, December 21, 2021).

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 continue to require the actions specified in AD 2021–25–12 and AD 2022–11–11 and would also require accomplishing the actions specified in the service information described previously. This proposed AD would also prohibit the installation of affected parts.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 41 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
Retained actions from AD 2021-25-12 *	1 work-hour × $85 per hour = $85	Negligible	$85	$3,485
Retained actions from AD 2022–11–11	4 work-hours × $85 per hour = $340	$8	348	14,268
New proposed actions	4 work-hours × $85 per hour = $340	$25,804	26,144	1,071,904
* Table does not include estimated costs for revising the maintenance or inspection program.

The FAA has determined that revising the maintenance or inspection program takes an average of 90 work-hours per operator, although the FAA recognizes that this number may vary from operator to operator. In the past, the FAA has estimated that this action takes 1 work-hour per airplane. Since operators incorporate maintenance or inspection program changes for their affected fleet(s), the FAA has determined that a per-operator estimate is more accurate than a per-airplane estimate. Therefore, the FAA estimates the total cost per operator to be $7,650 (90 work-hours × $85 per work-hour).

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

Estimated Costs of On-Condition Actions

Labor cost	Parts cost	Cost per product
2 work-hours × $85 per hour = $170	$8	$178

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) 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) 2021–25–12, Amendment 39–21856 ( 86 FR 72174, December 21, 2021); and AD 2022–11–11, Amendment 39–22061 (87 FR 33627, June 3, 2022); and

b. Adding the following new AD:

DeHavilland Aircraft of Canada (Type Certificate Previously Held by Bombardier, Inc.): Docket No. FAA–2024–0756; Project Identifier MCAI–2023–00549–T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by May 6, 2024.

(b) Affected ADs

This AD replaces AD 2021–25–12, Amendment 39–21856 (86 FR 72174, December 21, 2021) (AD 2021–25–12); and AD 2022–11–11, Amendment 39–22061 (87 FR 33627, June 3, 2022) (AD 2022–11–11).

(c) Applicability

This AD applies to De Havilland Aircraft of Canada Limited (Type Certificate previously held by Bombardier, Inc.) Model DHC–8–401 and –402 airplanes, certificated in any category, having serial numbers 4001, and 4003 through 4633 inclusive.

(d) Subject

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

(e) Reason

This AD was prompted by reports of a certain bolt at the pivot pin link being found missing or having stress corrosion cracking and a determination that the pivot pin and tow fitting assembly of the nose landing gear (NLG) must be replaced. The FAA is issuing this AD to address failure of the pivot pin retention bolt. The unsafe condition, if not addressed, could result in a loss of directional control or loss of an NLG tire during takeoff or landing, which could lead to runway excursions.

(f) Compliance

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

(g) Retained Maintenance or Inspection Program Revision, With No Changes

This paragraph restates the requirements of paragraph (g) of AD 2021–25–12, with no changes. For airplanes with pivot pin retention bolt part number (P/N) NAS6204–14D installed on the NLG assembly: Within 30 days after January 5, 2022 (the effective date of AD 2021–25–12), or within 30 days after installation of pivot pin retention bolt part number P/N NAS6204–14D, whichever occurs later, revise the existing maintenance or inspection program, as applicable, to incorporate the information for Structures Safe Life Task 32–21–01–701 and Task 32–21–01–702, as specified in De Havilland Aircraft of Canada Limited Temporary Revision ALI–0223, dated October 15, 2020. The initial compliance time for doing the tasks is at the applicable time specified in De Havilland Aircraft of Canada Limited Temporary Revision ALI–0223, dated October 15, 2020, or within 30 days after January 5, 2022, whichever occurs later; except, if replacement of bolt P/N NAS6204–14D was performed before January 5, 2022, as specified in De Havilland Aircraft of Canada Service Bulletin 84–32–161, the initial compliance time for Task 32–21–01–702 (bolt P/N NAS6204–14D replacement) is within 3 months after January 5, 2022, or within 800 flight cycles after performing the replacement, whichever occurs later.

(h) Retained No Alternative Actions or Intervals, With No Changes

This paragraph restates the requirements of paragraph (h) of AD 2021–25–12, with no changes. After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions ( e.g., replacements) or intervals may be used unless the actions and intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (n)(1) of this AD.

(i) Retained Repetitive Lubrications, With No Changes

This paragraph restates the requirements of paragraph (i) of AD 2021–25–12, with no changes. For airplanes with pivot pin retention bolt P/N NAS6204–14D installed on the NLG assembly: Within 30 days or 400 flight cycles, whichever occurs first after January 5, 2022 (the effective date of AD 2021–25–12), and thereafter at intervals not exceeding 400 flight cycles, lubricate the trailing arm of the NLG, including doing a general visual inspection of the NLG pivot pin mechanism for discrepancies ( i.e., bolt P/N NAS602–14D is missing or has damage ( e.g., stress corrosion or stress corrosion cracking)) and, as applicable, replacing the bolt before further flight, in accordance with paragraph 3.B. of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84–32–167, dated August 12, 2021.

(j) Retained Modification, With No Changes

This paragraph restates the requirements of paragraph (g) of AD 2022–11–11, with no changes. For any airplane having an NLG shock strut assembly, part number (P/N) 47100–XX (where XX represents any number), that has special bolt P/N 47205–1 or 47205–3: Within 1,600 flight cycles or 9 months after July 8, 2022 (the effective date of AD 2022–11–11), whichever occurs first, modify the NLG shock strut assembly, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84–32–161, Revision B, dated March 31, 2021, including UTC Aerospace Systems Service Bulletin 47100–32–145, Revision 3, dated March 26, 2021.

Note 1 to paragraph (j): After installing pivot pin retention bolt part number NAS6204–14D, paragraphs (g), (h), and (i) of this AD applies to pivot pin retention bolt part number NAS6204–14D.

(k) New Replacement

Within 8,000 flight hours or 48 months, whichever occurs first, after the effective date of this AD, remove pivot pin linkage components and replace pivot pin P/N 47127–1 or P/N 47127–3 and tow fitting assembly P/N 47160–1 with pivot pin P/N 47127–5 and tow fitting assembly P/N 47160–3, in accordance with Section 3.B. of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84–32–173, dated November 30, 2022, including Collins Aerospace Service Bulletin 47100–32–153, dated November 10, 2022. Accomplishing the replacement required by this paragraph terminates the requirements of paragraphs (g), (h), (i) and (j) of this AD.

(l) Credit for Previous Actions

This paragraph provides credit for actions required by paragraph (j) of this AD, if those actions were performed before July 8, 2022 (the effective date of AD 2022–11–11), using De Havilland Aircraft of Canada Limited Service Bulletin 84–32–161, dated April 7, 2020, including UTC Aerospace Systems Service Bulletin 47100–32–145, dated April 3, 2020; or De Havilland Aircraft of Canada Limited Service Bulletin 84–32–161, Revision A, dated January 27, 2021, including UTC Aerospace Systems Service Bulletin 47100–32–145, Revision 2, dated January 4, 2021.

(m) Parts Installation Prohibition

As of the effective date of this AD, no person may install pivot pin P/N 47127–1 or P/N 47127–3 as a replacement part for pivot pin P/N 47127–5 on De Havilland Aircraft of Canada Limited Model DHC–8–401 and DHC–8–402 airplanes.

(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) 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, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited'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–2023–22, dated March 30, 2023, for related information. This Transport Canada AD may be found in the AD docket at regulations.gov under Docket No. FAA–2024–0756.

(2) For more information about this AD, contact Deep Gaurav, 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) De Havilland Aircraft of Canada Service Bulletin 84–32–173, dated November 15, 2022, including Collins Aerospace Service Bulletin 47100–32–153, dated November 10, 2022.

Note 2 to paragraph (p)(3)(i): De Havilland issued De Havilland Service Bulletin 84–32–173, dated November 15, 2022, with Collins Aerospace Service Bulletin 47100–32–153, dated November 10, 2022, attached as one “merged” file for the convenience of affected operators.

(ii) [Reserved]

(4) The following service information was approved for IBR on July 8, 2022 (87 FR 33627, June 3, 2022).

(i) De Havilland Aircraft of Canada Limited Service Bulletin 84–32–161, Revision B, dated March 31, 2021, including UTC Aerospace Systems Service Bulletin 47100–32–145, Revision 3, dated March 26, 2021.

Note 3 to paragraph (p)(4)(i): De Havilland issued De Havilland Service Bulletin 84–32–161, Revision B, dated March 31, 2021, with UTC Aerospace Systems Service Bulletin 47100–32–145, Revision 3, dated March 26, 2021, attached as one “merged” file for the convenience of affected operators.

(ii) [Reserved]

(5) The following service information was approved for IBR on January 5, 2022 (86 FR 72174, December 21, 2021).

(i) De Havilland Aircraft of Canada Limited Service Bulletin 84–32–167, dated August 12, 2021.

(ii) De Havilland Aircraft of Canada Limited Temporary Revision ALI–0223, dated October 15, 2020.

(6) For service information identified in this AD, contact De Havilland Aircraft of Canada Limited, Dash 8 Series Customer Response Centre, 5800 Explorer Drive, Mississauga, Ontario, L4W 5K9, Canada; telephone North America (toll-free): 855–310–1013, Direct: 647–277–5820; email [e-mail]; website dehavilland.com.

(7) You may view this service information 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.

(8) 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 March 15, 2024.

Victor Wicklund,

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