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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2021-0106; Project Identifier AD-2020-00708-R]
          - 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 Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This proposed AD was prompted by an incident of a side facing utility seat detaching from wall attachment points. This proposed AD would require modifying certain side facing utility seats and observer seats. This proposed AD would also prohibit installing those seats unless the modification has been accomplished. 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 April 19, 2021.

# 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:                          (202) 493-2251.                    
      -  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.                    

                        For service information identified in this NPRM, contact your local Sikorsky Field Representative or Sikorsky's Service Engineering Group at Sikorsky Aircraft Corporation, Mailstop K100, 124 Quarry Road, Trumbull, CT 06611; telephone 1-800-946-4337 (1-800-Winged-S); email                         *wcs_cust_service_eng.gr-sik@lmco.com*. Operators may also log on to the Sikorsky 360 website at                         *https://www.sikorsky360.com*. 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 (817) 222-5110.                    

## Examining the AD Docket

                    You may examine the AD docket at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2021-0106; 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.                

# FOR FURTHER INFORMATION CONTACT:

                        Dorie Resnik, Aerospace Engineer, Aviation Safety Section, Boston ACO Branch, FAA, 1200 District Ave., Burlington, MA 01803; phone: (781) 238-7693; email:                         *dorie.resnik@faa.gov*.                    

# 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-2021-0106; Project Identifier AD-2020-00708-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 Dorie Resnik, Aerospace Engineer, Aviation Safety Section, Boston ACO Branch, FAA, 1200 District Ave., Burlington, MA 01803; phone: (781) 238-7693; email:                     *dorie.resnik@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

The FAA proposes to adopt a new AD for Sikorsky Model S-92A helicopters with certain Martin-Baker side facing utility seats and observer seats installed. This proposed AD was prompted by an incident of a side facing utility seat detaching from wall attachment points during dynamic testing. The root cause has been identified as a change in the finishing process of the main back tube. Due to design similarity, certain observer seats are also subject to this unsafe condition.

                    Accordingly, this proposed AD would require replacing the main back tube assembly in affected side facing utility seats and observer seats. This proposed AD would also prohibit installing those seats unless the main back tube assembly has been replaced. This condition, if not addressed, could result in increased surface friction in the direction of the seat attenuation, failure of proper utility seat attenuation during a crash event, excessive lumbar loads in an observer seat during a crash event, and subsequent excessive or fatal occupant injury.                          ( print page 12551)    

## 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 the same type design.

## Related Service Information Under 1 CFR Part 51

The FAA reviewed Martin-Baker Special Information Leaflet (SIL) No. 831, dated July 10, 2019 (SIL 831), for side facing utility seat supplier part number (P/N) MBCS12410AA001, and Martin-Baker SIL No. 833, dated July 11, 2019 (SIL 833), for observer seat supplier P/N MBCS12200 and MBCS7301-2. This service information specifies procedures for disassembling the seat, inspecting components, replacing the main back tube assembly (tube assembly, back main), and reassembling, testing, and marking the seat. SIL 831 and SIL 833 are attached to Sikorsky S-92A Helicopter Alert Service Bulletin 92-25-026, dated March 5, 2020 (ASB 92-25-026).

The FAA also reviewed ASB 92-25-026, which specifies procedures for preparing the helicopter for replacing the main back tube assembly by following SIL 831 or SIL 833, as applicable to your seat. This service information specifies removing existing placards, complying with the applicable SIL, reinstalling the removed placards, inspecting for foreign object debris (FOD), and cleaning.

                    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                     **ADDRESSES**                    .                

## Proposed AD Requirements in This NPRM

This proposed AD would require, within 125 hours time-in-service (TIS) or six months after the effective date of this AD, whichever occurs first, removing certain placards, accomplishing the actions specified in SIL 831 or SIL 833 already described, and reinstalling the previously removed placards.

## Differences Between This Proposed AD and the Service Information

ASB 92-25-026 specifies a compliance time of no later than March 5, 2021; where this proposed AD specifies a compliance time of within 125 hours TIS or six months after the effective date of this AD, whichever occurs first. ASB 92-25-026 specifies inspecting for FOD and cleaning; whereas this proposed AD does not. SIL 831 and SIL 833 specify destroying and disposing removed main back tube assemblies and discarding removed split pins and tie down straps; whereas this proposed AD would require removing those parts from service instead. The service information specifies recording compliance; whereas this proposed AD does not.

## Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 9 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.

Replacing a main back tube assembly would take about 2 work-hours and parts would cost about $11,217, for an estimated cost of about $11,387 per seat. Each helicopter could have up to 19 affected seats, which would take up to 38 work-hours and parts would cost up to about $213,123, for an estimated cost of up to about $216,353 per helicopter and $1,947,177 for the U.S. fleet.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.

## 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 

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

**Sikorsky Aircraft Corporation:**                         Docket No. FAA-2021-0106; Project Identifier AD-2020-00708-R.                    

## (a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by April 19, 2021.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to Sikorsky Aircraft Corporation Model S-92A helicopters, certificated in any category, with the following installed:

(1) A Martin-Baker side facing utility seat supplier part number (P/N) MBCS12410AA001 with a serial number (S/N) identified in Table 2 of Martin-Baker Special Information Leaflet (SIL) No. 831, dated July 10, 2019 (SIL 831), that is not marked with “SIL831 incorporated;” or

(2) A Martin-Baker observer seat supplier P/N MBCS12200 or MBCS7301-2 with an S/N identified in Table 2 of Martin-Baker SIL No. 833, dated July 11, 2019 (SIL 833), that is not marked with “SIL833 incorporated.”

# Note 1 to paragraph (c): 

SIL 831 and SIL 833 are attached to Sikorsky S-92A Helicopter Alert Service Bulletin 92-25-026, dated March 5, 2020 (ASB 92-25-026).

# Note 2 to paragraph (c): 

                            Section 3., the Accomplishment Instructions, Tables 1 and 2 of ASB 92-25-026, specify cross references                                   ( print page 12552)                                of Martin-Baker supplier P/Ns with Sikorsky P/Ns and kit P/Ns.                        

# Note 3 to paragraph (c): 

The marking “SIL831 incorporated” or “SIL833 incorporated,” as applicable, could be located adjacent to identification labels on the underside of the sitting platform assembly P/N MBCS4111.

## (d) Subject

Joint Aircraft System Component (JASC) Code: 2500, Cabin Equipment/Furnishings; and 2520, Passenger Compartment Equipment.

## (e) Unsafe Condition

This AD was prompted by an incident of a side facing utility seat detaching from wall attachment points during dynamic testing. The FAA is issuing this AD to detect and address a main back tube, a component of the main back tube assembly, which does not meet design requirements. The unsafe condition, if not addressed, could result in increased surface friction in the direction of the seat attenuation, failure of proper utility seat attenuation during a crash event, excessive lumbar loads in an observer seat during a crash event, and subsequent excessive or fatal occupant injury.

## (f) Compliance

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

## (g) Required Actions

(1) Within 125 hours time-in-service or six months after the effective date of this AD, whichever occurs first, replace each main back tube assembly by following Section 3., Accomplishment Instructions, paragraphs C. through E., of ASB 92-25-026; except where the service information referenced in ASB 92-25-026 specifies destroying and disposing of parts or discarding parts, this AD requires removing those parts from service instead.

# Note 4 to paragraph (g)(1): 

SIL 831 and SIL 833, referred to in ASB 92-25-026, refer to main back tube assembly as tube assembly, back main.

(2) As of the effective date of this AD, do not install a Martin-Baker side facing utility seat identified in paragraph (c)(1) of this AD or a Martin-Baker observer seat identified in paragraph (c)(2) of this AD unless the actions in paragraph (g)(1) have been accomplished.

## (h) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Boston ACO 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 certification office, send it to the attention of the person identified in paragraph (i)(1) of this AD.

(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) Related Information

                        (1) For more information about this AD, contact Dorie Resnik, Aerospace Engineer, Aviation Safety Section, Boston ACO Branch, FAA, 1200 District Ave., Burlington, MA 01803; phone: (781) 238-7693; email:                         *dorie.resnik@faa.gov*.                    

                        (2) For service information identified in this AD, contact your local Sikorsky Field Representative or Sikorsky's Service Engineering Group at Sikorsky Aircraft Corporation, Mailstop K100, 124 Quarry Road, Trumbull, CT 06611; telephone 1-800-946-4337 (1-800-Winged-S); email                         *wcs_cust_service_eng.gr-sik@lmco.com*. Operators may also log on to the Sikorsky 360 website at                         *https://www.sikorsky360.com*. 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 (817) 222-5110.                    

Issued on February 19, 2021.

Lance T. Gant,

Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2021-03950 Filed 3-3-21; 8:45 am]

BILLING CODE 4910-13-P