2021-27622. Airworthiness Directives; Bell Textron Canada Limited Helicopters

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 Bell Textron Canada Limited Model 429 helicopters. This proposed AD was prompted by reports of failed rivets between the tailboom skin and the tail rotor (TR) gearbox support assembly. This proposed AD would require visually inspecting the external surface of the TR gearbox support assembly, borescope inspecting or visually inspecting the inside of the tailboom for certain conditions, and performing a tactile inspection. Depending on the results of the inspections, this proposed AD would require removing certain rivets from service or repairing gaps in accordance with FAA-approved methods. This proposed AD would also require repeating these inspections within certain intervals. 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 February 7, 2022.

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 https://www.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 between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Bell Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J 1R4, Canada; telephone [phone] or 1-800-363-8023; fax [phone]; email [e-mail]; or at https://www.bellflight.com/​support/​contact-support. You may view this service information 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].

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-1074; 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 Transport Canada AD, any comments received, and other information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT:

Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., 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-2021-1074; Project Identifier MCAI-2021-00447-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 https://www.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 Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., 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

Transport Canada, which is the aviation authority for Canada, has issued Canadian AD CF-2021-15, dated April 14, 2021 (Transport Canada AD CF-2021-15), to correct an unsafe condition for Bell Textron Canada Limited Model 429 helicopters, serial numbers (S/N) 57001 and subsequent. Transport Canada advises of multiple in-service reports of failed rivets at the joint between the tailboom skin and the TR gearbox support assembly part number (P/N) 429-034-701-101 or P/N 429-035-705-101. Transport Canada states that in-service reports also revealed a quality escape resulted in a gapping condition between the tailboom skin and the TR gearbox support fitting at some locations around the joint, and that rivets of inadequate grip length have been installed at the affected joint. This condition, if not addressed, could result in progressive deterioration of the joint structural integrity, detachment of the TR gearbox support assembly and loss of control of the helicopter.

Accordingly, Transport Canada AD CF-2021-15 requires for certain serial-numbered helicopters an initial visual inspection of the rivets at the TR gearbox support assembly for signs of failed rivets or inadequate grip length. Transport Canada AD CF-2021-15 also requires, for all serial-numbered helicopters defined in the applicability, repeating the initial visual inspection at intervals not to exceed 400 hours air time or 12 months, whichever occurs first. Transport Canada AD CF-2021-15 also requires repair or replacement of affected parts if discrepancies are found. Transport Canada considers its AD an interim action and states that further AD action may follow.

FAA's Determination

These helicopters have been approved by the aviation authority of Canada and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with Canada, Transport Canada, its technical representative, has notified the FAA of 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.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bell Alert Service Bulletin 429-19-47, Revision B, dated January 27, 2021 (ASB 429-19-47). This service information specifies procedures for an initial and repetitive general visual inspections and detailed inspections of the affected rivets at the joint between the tailboom skin and the TR gearbox support assembly. This service information also specifies procedures for replacing the affected rivets and repairing the gaps in accordance with an approved Bell structural repair scheme.

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.

Proposed AD Requirements in This NPRM

For Model 429 helicopters with S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that, as of the effective date of this AD, have accumulated less than 300 total hours time-in-service (TIS), before accumulating 400 total hours TIS; or for helicopters with S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that, as of the effective date of this AD, have replaced certain part-numbered TR gearbox support assemblies and the helicopter has accumulated less than 300 total hours TIS since the replacement of the TR gearbox support assembly, before accumulating 400 total hours TIS since the replacement, this proposed AD would require visually inspecting the external surface of the TR gearbox support assembly for any rivet heads that have separated from their tail, measuring any gaps, and before further flight, removing affected rivets from service or repairing gaps in accordance with FAA-approved methods.

This proposed AD would also require either borescope inspecting or using a light source and mirror to visually inspect each rivet inside the tailboom for missing rivet tails, rivet tails not resting against the tailboom skin, and any rivet tails resting at the bottom of the tailboom. Depending on the inspection results, this proposed AD would require, before further flight, additional inspections or removing certain parts from service. This proposed AD would require performing a tactile inspection of certain rivets identified in the applicable service information and depending on the inspection results, removing rivets from service before further flight.

For Model 429 helicopters with S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that are not identified in paragraph (g)(1) of this AD, this proposed AD would require, within 100 hours TIS after the effective date of this AD, performing the visual inspection of the TR gearbox support assembly, visually inspecting or borescope inspecting each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously.

For Model 429 helicopters S/N 57002 through 57210 inclusive and S/N 57212 and subsequent this proposed AD would require, within 400 hours TIS after the initial inspections required by this proposed AD, as applicable to your helicopter, and thereafter at intervals not to exceed 400 hours TIS, performing the visual inspection of the TR gearbox support assembly, visually inspecting or borescope inspecting each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously.

For Model 429 helicopters S/N 57001 and 57211, this proposed AD would require, within 400 hours TIS after the effective date of this proposed AD and thereafter at intervals not to exceed 400 hours TIS, performing the visual inspection of the TR gearbox support assembly, visually inspecting or borescope inspecting each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously.

Differences Between This Proposed AD and the Transport Canada AD

Transport Canada AD CF-2021-15 requires replacing any rivets, and repairing any gaps that exceed 0.005 in (0.127 mm), in accordance with an approved Bell structural repair scheme, and submitting certain information to the manufacturer, whereas this proposed AD would require removing the rivets from service and repairing the gaps using an FAA-approved method instead. Transport Canada AD CF-2021-15 requires replacing any rivets if any gaps are 0.005 in (0.127mm) or less, whereas this proposed AD would require removing the rivets from service.

Transport Canada AD CF-2021-15 also requires for certain serial-numbered helicopters that have accumulated less than 300 hours air time, or have replaced a certain part-numbered TR gearbox support assembly and have accumulated less than 300 hours air time since the replacement, within 100 hours air time or 6 months upon reaching 300 hours air time, whichever occurs first, performing the visual inspection of the TR gearbox support assembly, visually inspecting or borescope inspecting each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously, whereas this proposed AD would require these actions for certain helicopters before accumulating 400 total hours TIS and for certain other helicopters, before the helicopter accumulates 400 total hours TIS since the replacement of a certain part-numbered TR gearbox support assembly.

Additionally, Transport Canada AD CF-2021-15 requires for certain serial-numbered helicopters that have accumulated 300 hours air time or more, or have replaced a certain part-numbered TR gearbox support assembly and have accumulated 300 hours air time or more since the replacement, within 100 hours air time or 6 months, whichever occurs first, performing the visual inspection of the TR gearbox support assembly, visually inspecting or borescope inspecting each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously, whereas this proposed AD would require these actions within 100 hours TIS after the effective date of this AD.

Finally, Transport Canada AD CF-2021-15 requires repeating the visual inspection of the TR gearbox support assembly, the visual inspection or borescope inspection of each rivet inside the tailboom, performing the tactile inspection, and accomplishing the applicable corrective actions described previously at intervals not to exceed 400 hours air time or 12 months, whichever occurs first, whereas this proposed AD would require for certain serial-numbered helicopters, the repetitive inspections to occur within 400 hours TIS after the effective date of this AD, and thereafter at intervals not to exceed 400 hours TIS.

Interim Action

The FAA considers this proposed AD would be an interim action. Once final action has been identified, the FAA might consider further rulemaking.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 120 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 surface of the TR gearbox support assembly would take about 0.5 work-hour for an estimated cost of $43 per inspection and $5,160 for the U.S. fleet per inspection.

If required, replacing any affected rivets would take about 1 work-hour and parts would cost about $110 per rivet for an estimated cost of $195 per rivet replacement.

If required, measuring gaps would take about 0.5 work-hour for an estimated cost of $43 per helicopter.

If required, repairing any gaps would take up to about 1 work-hour for an estimated cost of up to $85 per repair.

Visually inspecting or borescope inspecting the inside of the tailboom would take about 0.5 work-hour for an estimated cost of $43 per inspection and $5,160 for the U.S. fleet per inspection.

Performing a tactile inspection would take about 0.5 work-hour for an estimated cost of $43 per inspection and $5,160 for the U.S. fleet per inspection.

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, 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:

Bell Textron Canada Limited: Docket No. FAA-2021-1074; Project Identifier MCAI-2021-00447-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by February 7, 2022.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Bell Textron Canada Limited Model 429 helicopters, serial numbers (S/N) 57001 and subsequent, certificated in any category.

(d) Subject

Joint Aircraft Service Component (JASC) Code: 5302, Rotorcraft tail boom.

(e) Unsafe Condition

This AD was prompted by reports of failed rivets between the tailboom skin and the tail rotor (TR) gearbox support assembly. The FAA is issuing this AD to detect failed rivets and rivets with inadequate grip length. The unsafe condition, if not addressed, could result in deterioration of the joint structural integrity, detachment of the TR gearbox support assembly, and loss of helicopter control.

(f) Compliance

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

(g) Required Actions

(1) As of the effective date of this AD, for Model 429 helicopters S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that have accumulated less than 300 total hours time-in-service (TIS), before accumulating 400 total hours TIS; or for Model 429 helicopters S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that have replaced the TR gearbox support assembly part number (P/N) 429-034-701-101 or P/N 429-035-705-101 and the helicopter has accumulated less than 300 total hours TIS since the replacement of the TR gearbox support assembly, before accumulating 400 total hours TIS since the replacement:

(i) Visually inspect the external surface of the TR gearbox support assembly for any rivet heads that have separated from their tail. If there are any rivet heads that have separated from their tail, before further flight, measure any gaps between the TR gearbox support assembly and the tailboom skin by following the Accomplishment Instructions, Part I, paragraphs 9.b. through 9.d of Bell Alert Service Bulletin 429-19-47, Revision B, dated January 27, 2021 (ASB 429-19-47 Rev B).

(A) If there are no gaps or if any gap measures less than 0.005 in (0.127 mm), before further flight, remove the rivets from service.

(B) If there are any gaps that are equal to or exceed 0.005 in (0.127 mm), before further flight, repair the gaps in accordance with an FAA-approved method, and remove the rivets from service.

(ii) Borescope inspect or use a light source and mirror to visually inspect each rivet inside the tailboom for any missing rivet tails, any rivet tails resting at the bottom of the tailboom, and any rivet tails not resting against the tailboom skin.

(A) If there are any missing rivet tails, or any rivet tails resting at the bottom of the tailboom, before further flight, measure any gaps between the TR gearbox support assembly and the tailboom skin by following the Accomplishment Instructions, Part I, paragraphs 9.b. through 9.d of ASB 429-19-47 Rev B, and perform the corrective actions specified in paragraphs (g)(1)(i)(A) or (B) of this AD as applicable.

(B) If there are any rivet tails not resting against the tailboom skin before further flight, remove the rivets from service.

(iii) Perform a tactile inspection of the rivets identified in Figure 1 of ASB 429-19-47 Rev B, by pulling on each rivet tail with pliers or pulling by hand. If any rivet does not come out when pulled with pliers or when pulled by hand, before further flight, remove the rivet from service.

(2) For Model 429 helicopters S/N 57002 through 57210 inclusive and S/N 57212 and subsequent that are not identified in paragraph (g)(1) of this AD, within 100 hours TIS after the effective date of this AD, perform the actions as specified in paragraph (g)(1)(i) through (iii) of this AD.

(3) For Model 429 helicopters S/N 57002 through 57210 inclusive and S/N 57212 and subsequent, within 400 hours TIS after the initial inspections required by paragraph (g)(1) or (2) of this AD, as applicable to your helicopter, and thereafter at intervals not to exceed 400 hours TIS, accomplish the actions required by paragraphs (g)(1)(i) through (iii) of this AD.

(4) For Model 429 helicopters S/N 57001 and 57211, within 400 hours TIS after the effective date of this AD, and thereafter at intervals not to exceed 400 hours TIS, accomplish the actions required by paragraphs (g)(1)(i) through (iii) of this AD.

(h) Credit for Previous Actions

This paragraph provides credit for the actions specified in paragraphs (g)(1) and (2) of this AD, if those actions were performed before the effective date of this AD using Bell Alert Service Bulletin 429-19-47, Revision A, dated November 2, 2020, or Bell Alert Service Bulletin 429-19-47, dated August 28, 2019.

(i) Alternative Methods of Compliance (AMOCs)

(1) 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (j)(1) 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.

(j) Related Information

(1) For more information about this AD, contact Andrea Jimenez, Aerospace Engineer, COS Program Management Section, Operational Safety Branch, Compliance & Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone [phone]; email [e-mail] .

(2) For service information identified in this AD, contact Bell Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J 1R4, Canada; telephone [phone] or 1-800-363-8023; fax [phone]; email [e-mail] ; or at https://www.bellflight.com/​support/​contact-support . You may view this referenced service information 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].

(3) The subject of this AD is addressed in Transport Canada AD CF-2021-15, dated April 14, 2021. You may view the Transport Canada AD on the internet at https://www.regulations.gov in Docket No. FAA-2021-1074.

Issued on December 15, 2021.

Ross Landes,

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