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

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This AD was prompted by reports of moisture in the wing-to-fuselage joint, between the mating front spar and rear spar frame segments. This AD requires a visual inspection of the fuselage front and rear spar frames, an ultrasonic test if applicable, other specified actions, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective August 21, 2024.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of August 21, 2024.

ADDRESSES:

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2023-1885; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Material Incorporated by Reference:

• For De Havilland Aircraft material incorporated by reference 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 855-310-1013 or 647-277-5820; emailthd@dehavilland.com; website dehavilland.com.
• You may view this material 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 atregulations.gov under Docket No. FAA-2023-1885.

FOR FURTHER INFORMATION CONTACT:

Deep Gaurav, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email deep.gaurav@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. The NPRM published in the Federal Register on September 25, 2023 (88 FR 65635). The NPRM was prompted by AD CF-2022-63, dated November 17, 2022, issued by Transport Canada, which is the aviation authority for Canada (referred to after this as the MCAI). The MCAI states several reports of moisture have been found in the wing-to-fuselage joint, between the mating front spar and rear spar frame segments. This condition, if not corrected, could lead to corrosion and structural degradation of the wing-to-fuselage joint and possible wing separation from the airplane.

In the NPRM, the FAA proposed to require a visual inspection of the fuselage front and rear spar frames, an ultrasonic test if applicable, other specified actions, and repair if necessary. The FAA is issuing 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-2023-1885.

Discussion of Final Airworthiness Directive

Comments

The FAA received a comment from De Havilland. The following presents the comment received on the NPRM and the FAA's response.

Request To Update the Service Information

De Havilland stated that to allow some operators to accomplish the AD, an update is necessary to the work instructions in De Havilland Aircraft of Canada Limited Service Bulletin 84-53-81, Revision A, dated August 23, 2022. The service bulletin is in the process of being revised to allow operators an alternative means of accessing the front spar joint via the forward fairing rib on certain airplanes.

To allow operators to use later revisions of the referenced document (issued after publication of the AD), either the FAA must revise the AD to reference specific later revisions, or operators may request approval to use later revisions as an alternative method of compliance with this AD under the provisions of paragraph (i)(1) of this AD.

In light of the critical nature of the identified unsafe condition ( i.e., corrosion and structural degradation of the wing-to-fuselage joint), the FAA does not consider it warranted to delay the issuance of this final rule until the revised service information is published. The FAA has not changed this AD in this regard.

Conclusion

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 referenced above. The FAA reviewed the relevant data, considered the comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on this product. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed De Havilland Aircraft of Canada Limited Service Bulletin 84-53-81, Revision A, dated August 23, 2022. This material specifies procedures for a general visual inspection of the fuselage front and rear spar frames (including around the frame bolts) for signs of moisture ( i.e., stains and streaks). If signs of moisture ingress are noted in the affected structure because of this inspection, then an ultrasonic test and other specified actions will be required, which includes installing a sealant plug, refinishing the frame edge sealing, and removing the existing frame recess sealant between the frame and struts in the cabin.

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.

Costs of Compliance

The FAA estimates that this AD affects 41 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

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

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(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 Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2024-12-06 De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.): Amendment 39-22770; Docket No. FAA-2023-1885; Project Identifier MCAI-2022-01484-T.

(a) Effective Date

This airworthiness directive (AD) is effective August 21, 2024.

(b) Affected ADs

None.

(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 4624 inclusive.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by reports of moisture in the wing-to-fuselage joint, between the mating front spar and rear spar frame segments. The FAA is issuing this AD to address potential corrosion and structural degradation of the wing-to-fuselage joint. The unsafe condition, if not addressed, could result in wing separation from the airplane.

(f) Compliance

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

(g) Inspection and Corrective Action

At the applicable compliance times specified in paragraph (g)(1) or (2) of this AD, in accordance with Section 3.B., of the Accomplishment Instructions of De Havilland Aircraft of Canada Service Bulletin 84-53-81, Revision A, dated August 23, 2022, complete a general visual inspection of the fuselage spar frames and around the frame bolts for signs of moisture ingress ( i.e., stains and streaks), accomplish other specified actions, and if necessary, perform an ultrasonic test. Do all applicable ultrasonic tests before further flight. If, during any ultrasonic test, any corrosion or structural degradation is found, before further flight, repair 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.

(1) For airplanes that, as of the effective date of this AD, have accumulated less than 32,000 total flight cycles: before accumulating 40,000 total flight cycles.

(2) For airplanes that, as of the effective date of this AD, have accumulated 32,000 or more total flight cycles: within 8,000 flight hours or 48 months, whichever occurs first after the effective date of this AD.

(h) Credit for Previous Actions

This paragraph provides credit for actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD using De Havilland Aircraft of Canada Limited Service Bulletin 84-53-81, dated May 27, 2022.

(i) Additional AD Provisions

The following provisions also apply to this AD:

(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, International Validation Branch, mail it to the address identified in paragraph (j) of this AD or email to 9-AVS-AIR-730-AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.

(2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or Transport Canada; or De Havilland Aircraft of Canada Limited's Transport Canada DAO. If approved by the DAO, the approval must include the DAO-authorized signature.

(j) Additional Information

For more information about this AD, contact Deep Gaurav, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; email deep.gaurav@faa.gov.

(k) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this material as applicable to do the actions required by this AD, unless this AD specifies otherwise.

(i) De Havilland Aircraft of Canada Limited Service Bulletin 84-53-81, Revision A, dated August 23, 2022.

(ii) [Reserved]

(3) For De Havilland Aircraft material incorporated by reference 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 855-310-1013 or 647-277-5820; email thd@dehavilland.com; website dehavilland.com.

(4) You may view this material 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.

(5) 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-locationsoremailfr.inspection@nara.gov.