2024-17318. Airworthiness Directives; MD Helicopters, LLC, Helicopters

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Department of Transportation

Federal Aviation Administration

1. 14 CFR Part 39
2. [Docket No. FAA-2024-2009; Project Identifier AD-2023-01286-R]
3. RIN 2120-AA64

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain MD Helicopters, LLC, Model 369 (Army YOH-6A), 369A (Army OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This proposed AD was prompted by multiple reports of cracked tail rotor (T/R) pedal support brackets. This proposed AD would require repetitively inspecting certain part-numbered T/R pedal support brackets and depending on the results, replacing the T/R pedal support bracket or refinishing any exposed areas. This proposed AD would also prohibit installing certain part-numbered T/R pedal support brackets. 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 October 15, 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 r egulations.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-2024-2009; 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: ( print page 68838)

• For MD Helicopters material identified in this AD, contact MD Helicopters, LLC, 4555 East McDowell Road, Mesa, AZ 85215-9734; phone: [phone]; email:[e-mail]; website: mdhelicopters.com/contact/.
• You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call [phone].

FOR FURTHER INFORMATION CONTACT:

Eduardo Orozco-Duran, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: [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 the ADDRESSES section. Include “Docket No. FAA-2024-2009; Project Identifier AD-2023-01286-R” 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 Eduardo Orozco-Duran, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: [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 received a report of a forced emergency landing involving an MD Helicopters, LLC, Model 369D helicopter in Canada in 2022 that was caused by a cracked magnesium cast T/R pedal support bracket having part number (P/N) 369A7505-8. There have been 16 other reports of cracked magnesium cast T/R pedal support brackets having P/Ns 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15 discovered during maintenance in the last 30 years. Material deficiencies associated with magnesium cast parts, as well as fatigue damage and successive in-flight loading have been determined to cause the parts to fail. Additionally, magnesium cast parts are susceptible to corrosion where insufficient protective coatings have shown to wear and deteriorate. All reported failures of this part have been the magnesium cast 369A7505 configuration. The aluminum cast T/R pedal support bracket P/N 369N2640 have no reported failures but are still subject to the inspection requirements of this AD. The natural corrosion advantages of aluminum, as well as the coating requirements of its anodization offer greater mitigation of the risks of corrosion in comparison to the magnesium cast part. Although superior to the magnesium cast part, the alternate aluminum cast part could still be prone to these material deficiencies of cast parts.

This proposed AD would require repetitively inspecting magnesium cast T/R pedal support brackets having P/N 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15, and aluminum cast T/R pedal support brackets having P/N 369N2640-1 or 369N2640-2. These T/R pedal support brackets may be installed on MD Helicopters, LLC, Model 369 (Army YOH-6A), 369A (Army OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This proposed AD would also prohibit installing magnesium cast T/R pedal support bracket P/N 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15 on any helicopter. This condition, if not addressed, could result in failure of the T/R pedal support bracket, reduced controllability of the helicopter, and subsequent loss of control of the helicopter.

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 these same type designs.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed MD Helicopters Service Bulletin SB369D-231R2 for Model 369D helicopters, SB369E-131R2 for Model 369E helicopters, SB369F-122R2 for Model 369F and 369FF helicopters, SB369H-265R2 for Model 369H, 369HE, 369HM, and 369HS helicopters, SB500N-068R2 for Model 500N helicopters, and SB600N-082R2 for Model 600N helicopters, each dated November 1, 2023 (co-published as one document). For magnesium cast T/R pedal support brackets P/N 369A7505-7, 369A7505-8, 369A7505-14, and 369A7505-15, this material specifies procedures for visually inspecting each T/R pedal support bracket for a crack and corrosion and depending on the results, replacing the bracket with an aluminum cast T/R pedal support bracket having P/N 369N2640-1 or 369N2640-2, or refinishing any exposed areas. For magnesium cast T/R pedal support brackets P/N 369A7505-7, 369A7505-8, 369A7505-14, and 369A7505-15, this material also specifies procedures for fluorescent penetrant inspecting, eddy current inspecting, or dye penetrant inspecting each T/R pedal support bracket for a crack and depending on the results, replacing the bracket with an aluminum cast T/R pedal support bracket having P/N 369N2640-1 or 369N2640-2, or refinishing any exposed areas. For the purposes of this proposed AD, MD Helicopters, LLC, Model 369 (Army YOH-6A) and 369A (Army OH-6A) helicopters would use MD Helicopters Service Bulletin SB369D-231R2, dated November 1, 2023, to accomplish certain actions required by this proposed AD.

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.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in the material already described except as discussed under “Differences Between ( print page 68839) this Proposed AD and the Referenced Material.”

Differences Between This Proposed AD and the Referenced Material

The related material applies to magnesium cast T/R pedal support brackets having P/N 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15, whereas this proposed AD would apply to those part-numbered magnesium cast T/R pedal support brackets and aluminum cast T/R pedal support brackets having P/N 369N2640-1 or 369N2640-2. This proposed AD would prohibit installing magnesium cast T/R pedal support brackets having P/N 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15, whereas the related material does not.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 353 helicopters of U.S. registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this proposed AD.

Visually inspecting the T/R pedal support brackets (up to two T/R pedal support brackets per helicopter) would take approximately 0.5 work-hour for an estimated cost of up to $43 per helicopter and $15,179 for the U.S. fleet per inspection cycle. Non-destructive inspection of the T/R pedal support brackets would take approximately 2 work-hours for an estimated cost of up to $170 per helicopter and $60,010 for the U.S. fleet per inspection cycle.

If required, replacing a T/R pedal support bracket would take approximately 8 work-hours and parts would cost approximately $2,075 for an estimated cost of $2,755 per T/R pedal support bracket. Refinishing any exposed areas could vary significantly from helicopter to helicopter. The FAA has no data to determine the costs to accomplish this action or the number of helicopters that may require this action.

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 adding the following new airworthiness directive:

MD Helicopters, LLC: Docket No. FAA-2024-2009; Project Identifier AD-2023-01286-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by October 15, 2024.

(b) Affected ADs

None.

(c) Applicability

This AD applies to MD Helicopters, LLC, Model 369 (Army YOH-6A), 369A (Army OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, certificated in any category, with a tail rotor (T/R) pedal support bracket part number (P/N) 369A7505-7, 369A7505-8, 369A7505-14, 369A7505-15, 369N2640-1, or 369N2640-2, installed.

(d) Subject

Joint Aircraft System Component (JASC) Code: 6720, tail rotor control system.

(e) Unsafe Condition

This AD was prompted by multiple reports of cracked T/R pedal support brackets. The FAA is issuing this AD to detect a cracked T/R pedal support bracket. The unsafe condition, if not addressed, could result in failure of the T/R pedal support bracket, reduced controllability of the helicopter, and subsequent loss of control of the helicopter.

(f) Compliance

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

(g) Required Actions

(1) Within 25 hours time-in-service (TIS) and thereafter at intervals not to exceed 100 hours TIS, using a 10X power magnification glass, mirror, and flashlight, visually inspect each T/R pedal support bracket for cracks and corrosion by following the Accomplishment Instructions, paragraph 2.A.(2)., of MD Helicopters Service Bulletin SB369D-231R2, SB369E-131R2, SB369F-122R2, SB369H-265R2, SB500N-068R2, or SB600N-082R2, each dated November 1, 2023 (collectively referred to as “the service bulletins”), as applicable to your helicopter model; you may use a borescope as specified in the note in paragraph 2.A.(2) of the service bulletins. For the purposes of this AD, for MD Helicopters, LLC, Model 369 (Army YOH-6A) and 369A (Army OH-6A) helicopters, use MD Helicopters Service Bulletin SB369D-231R2, dated November 1, 2023, to accomplish the actions required by this AD.

(i) If there is a crack or any corrosion as a result of the inspections required by the introductory text of paragraph (g)(1) of this AD, before further flight, remove the T/R pedal support bracket from service and replace it with an airworthy T/R pedal support bracket P/N 369N2640-1 or 369N2640-2.

(ii) If there is not a crack and there is no corrosion as a result of the inspections required by the introductory text of paragraph (g)(1) of this AD, before further flight, refinish any exposed areas.

(2) Within 50 hours TIS and thereafter at intervals not to exceed 300 hours TIS, eddy current, dye penetrant, or fluorescent penetrant inspect each T/R pedal support bracket for a crack by following the Accomplishment Instructions, paragraph 2.B.(2)., of the service bulletins, as applicable to your helicopter model. The inspections required by this paragraph must be performed by a Level II or Level III inspector certified in the FAA-acceptable standards for nondestructive inspection personnel.

Note 1 to the introductory text of paragraph (g)(2): Advisory Circular 65-31B contains examples of FAA-acceptable Level II and Level III qualification standards criteria ( print page 68840) for inspection personnel doing nondestructive test inspections.

(i) If there is a crack as a result of the actions required by the introductory text of paragraph (g)(2) of this AD, before further flight, remove the T/R pedal support bracket from service and replace it with an airworthy T/R pedal support bracket P/N 369N2640-1 or 369N2640-2.

(ii) If there is not a crack as a result of the actions required by the introductory text of paragraph (g)(2) of this AD, before further flight, refinish any exposed areas.

(3) As of the effective date of this AD, do not install magnesium cast T/R pedal support bracket P/N 369A7505-7, 369A7505-8, 369A7505-14, or 369A7505-15 on any helicopter.

(h) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Western Certification 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the Western Certification Branch, send it to the attention of the person identified in paragraph (i) 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 local flight standards district office/certificate holding district office.

(i) Additional Information

(1) For more information about this AD, contact Eduardo Orozco-Duran, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: [phone]; email: [e-mail].

(2) For advisory circular material identified in this AD that is not incorporated by reference, go to faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1023552.

(j) 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 the AD specifies otherwise.

(i) MD Helicopters Service Bulletin SB369D-231R2, dated November 1, 2023.

(ii) MD Helicopters Service Bulletin SB369E-131R2, dated November 1, 2023.

(iii) MD Helicopters Service Bulletin SB369F-122R2, dated November 1, 2023.

(iv) MD Helicopters Service Bulletin SB369H-265R2, dated November 1, 2023.

(v) MD Helicopters Service Bulletin SB500N-068R2, dated November 1, 2023.

(vi) MD Helicopters Service Bulletin SB600N-082R2, dated November 1, 2023.

Note 2 to paragraph (j)(2): The service bulletins identified in paragraphs (j)(2)(i) through (vi) of this AD are co-published as one document.

(3) For MD Helicopters material identified in this AD, contact MD Helicopters, LLC, 4555 East McDowell Road, Mesa, AZ 85215-9734; phone: [phone]; email: [e-mail]; website: mdhelicopters.com/contact/.

(4) You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call [phone].

(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-locations or email [e-mail].

Issued on July 31, 2024.

Victor Wicklund,

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