Airworthiness Directives; Airbus Helicopters

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-2024-2419; Project Identifier MCAI-2023-00366-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 Dan McCully, Aviation Safety Engineer, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; phone: (404) 474-5548; email: william.mccully@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2023-0044, dated February 28, 2023, (EASA AD 2023-0044) to correct an unsafe condition on Airbus Model AS 350 B, AS 350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350 B3, EC 130 B4, EC 130 T2, AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, AS355 N, and AS355 NP helicopters. EASA advises that after a fleet design review for detection of particles in the MGB, it was determined that additional maintenance actions are necessary to improve detection of particles in the MGB. The FAA is proposing this AD to detect and correct the presence of particles in the MGB, which if not addressed, could result in reduced or loss of control of the helicopter.

You may examine EASA AD 2023-0044 in the AD docket at regulations.gov under Docket No. FAA-2024-2419.

Material Incorporated by Reference Under 1 CFR Part 51

EASA AD 2023-0044 requires repetitive borescope visual inspections of the bevel wheel of the affected MGB for particles, collecting and analyzing any found particles, and depending on the results, further actions, accomplishing corrective action in accordance with the ASB defined within, or contacting AH [Airbus Helicopters] for further corrective action. EASA AD 2023-0044 also requires accomplishing a borescope visual inspection of the bevel wheel of the affected MGB for particles following the detection of any particles at the MGB magnetic plug during accomplishment of certain maintenance tasks and depending on the results, taking corrective action. Lastly, EASA AD 2023-0044 prohibits installing an affected MGB on any helicopter unless it is a serviceable part as defined within and certain requirements are met.

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.

Other Related Material

The FAA reviewed Airbus Alert Service Bulletin No. AS350-05.01.04, No. AS355-05.00.87, and No. EC130-05A040, each Revision 0, and each dated January 25, 2023. This material specifies procedures for borescope inspecting the MGB bevel wheel for particles and, depending on the results, replacing a damaged epicyclic module or bevel reduction module with an airworthy part, and collecting the particles using a vacuum pump and analyzing the particles.

FAA's Determination

These helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the European Union, EASA has notified the FAA about the unsafe condition described in its AD. The FAA is proposing this AD after evaluating all known relevant information and determining that the unsafe condition described previously is likely to exist or develop on other helicopters of these same type designs.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in EASA AD 2023-0044, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this proposed AD and except as discussed under “Differences Between this Proposed AD and EASA AD 2023-0044.”

This proposed AD would require certain actions within compliance times specified in certain material referenced for compliance in EASA AD 2023-0044, particularly for corrective actions for scales, flakes, or splinters. Depending on the measurements of the scales, flakes, or splinters, corrective actions include close monitoring, metallurgical analysis within 50 hours time-in-serivce, or removing each affected module and additional actions when certain criteria are exceeded.

Explanation of Required Compliance Information

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate EASA AD 2023-0044 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2023-0044 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2023-0044 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2023-0044. Material referenced in EASA AD 2023-0044 for compliance will be available at www.regulations.gov by searching for and locating Docket No. FAA-2024-2419 after the FAA final rule is published.

Differences Between This Proposed AD and EASA AD 2023-0044

EASA AD 2023-0044 applies to Model AS350BB helicopters, whereas this proposed AD would not because that model is not FAA-type certificated.

Where Note 1 in the material referenced in EASA AD 2023-0044 specifies the option of 1 mechanical technician and 1 crew member, for this proposed AD, the pilot is only permitted to turn the tail rotor (b) because the other actions specified in the note must be accomplished by persons authorized under 14 CFR 43.3. Therefore, for the purposes of this proposed AD, the owner/operator (pilot) may turn the tail rotor (b) and must enter compliance with the applicable paragraph of this proposed AD in the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The pilot may perform this action because it only involves turning the tail rotor (b). This action can be performed equally well by a pilot or a mechanic. This action is an exception to the FAA's standard maintenance regulations.

This proposed AD would not require complying with paragraph (2) of EASA AD 2023-0044. Instead, this proposed AD would require repetitively inspecting the MGB magnetic plug for particles and, if there is any particle, accomplishing a borescope visual inspection, as specified in paragraphs (h)(6)(i) and (ii) of this proposed AD.

Where the material referenced in EASA AD 2023-0044 specifies contacting Airbus Helicopters for a certain action, this proposed AD would require accomplishing action in accordance with a method approved the FAA, EASA, or Airbus Helicopters' EASA Design Organization Approval.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 522 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.

A repetitive visual borescope inspection of the MGB bevel wheel would take 1 work-hour for an estimated cost of $85 per helicopter and $44,370 for the U.S. fleet, per inspection cycle.

If necessary, collecting and performing a metallurgical analysis of the detected particles would take 6 work-hours for an estimated cost of $510 per helicopter, per analysis.

Repetitively inspecting the magnetic plugs of the MGB would take 1 work-hour for an estimated cost of $85 per helicopter and $44,370 for the U.S. fleet, per inspection cycle.

If required, close monitoring would take 2 work-hours for an estimated cost of $170 per helicopter, per close monitoring cycle.

Accomplishing a visual borescope inspection of the MGB bevel wheel as a result of an MGB magnetic plug inspection would take 1 work-hour for an estimated cost of $85 per helicopter.

If necessary, replacing an epicyclic module would take 56 work-hours and parts would cost $50,524 (overhauled) for an estimated cost of $55,284 per module.

If necessary, replacing a bevel reduction module would take 56 work-hours and parts would cost $18,500 (overhaled) for an estimated cost of $23,260 per module.

Certain corrective action could vary significantly from helicopter to helicopter. The FAA has no data to determine the costs to accomplish the corrective 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.

The Proposed Amendment

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

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:

Airbus Helicopters: Docket No. FAA-2024-2419; Project Identifier MCAI-2023-00366-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by December 20, 2024.

(b) Affected ADs

None.

(c) Applicability

This AD applies to all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters, certificated in any category.

(d) Subject

Joint Aircraft System Component (JASC) Code: 6320, Main Rotor Gearbox.

(e) Unsafe Condition

This AD was prompted by an assessment performed by the manufacturer which determined that additional actions are necessary to improve particle detection for main gearboxes (MGBs) with certain part-numbered planet gear bearings installed. The FAA is issuing this AD to detect and correct particles in the MGB. The unsafe condition, if not addressed, could result in reduced or loss of control of the helicopter.

(f) Compliance

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

(g) Requirements

Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency AD 2023-0044, dated February 28, 2023 (EASA AD 2023-0044).

(h) Exceptions to EASA AD 2023-0044

(1) Where EASA AD 2023-0044 defines “serviceable MGB” as “An affected MGB which has accumulated less than 330 flight hours (FH) since new (first installation on a helicopter), or since an overhaul, or since an inspection in accordance with the instructions of the ASB;” for this AD, replace that text with “An affected MGB which has accumulated less than 330 total hours time-in-service since new (zero total hours time-in-service), since last overhaul if an overhaul has been accomplished, or since last inspection and any specified corrective action in accordance with the instructions of the ASB if an inspection and any specified corrective action by following the instructions of the ASB have been accomplished.”

(2) Where EASA AD 2023-0044 requires compliance in terms of flight hours, this AD requires using hours time-in-service (TIS).

(3) Where EASA AD 2023-0044 refers to its effective date, this AD requires using the effective date of this AD.

(4) Where Note 1 in the material referenced in paragraph (1) of EASA AD 2023-0044 specifies the option of 1 mechanical technician and 1 crew member, for this AD, the pilot is only permitted to turn the tail rotor (b). The owner/operator (pilot) holding at least a private pilot certificate may turn the tail rotor (b) and must enter compliance with paragraph (g) of this AD in the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.43. All other actions specified in Note 1 in the material referenced in paragraph (1) of EASA AD 2023-0044 must be accomplished by persons authorized under 14 CFR 43.3.

(5) Where Note 2 in the material referenced in paragraph (1) of EASA AD 2023-0044 specifies contacting Airbus Helicopters for further instructions if the bottom of the radius (a6) of the bevel wheel (a3) or head screws (a4) (see Figure 2) are not clearly visible, this AD requires, before further flight, accomplishing action in accordance with a method approved by the FAA, EASA, or Airbus Helicopters' EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.

(6) Instead of complying with paragraph (2) of EASA AD 2023-0044, comply with the actions required by paragraphs (h)(6)(i) and (ii) of this AD.

(i) After the effective date of this AD, and within the compliance time intervals specified table 1 to paragraph (h)(6)(i) of this AD, visually inspect the MGB magnetic plug for particles.

Note 1 to paragraph (h)(6)(i): Aircraft Maintenance Manual (AMM) task 60-00-00, 6-2A, or AMM task 60-00-00, 6-2, or work card 60-00-00-602, as applicable, provides information regarding inspecting the MGB magnetic plug.