Document ID: FAA-2021-0106-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Sikorsky Aircraft Corporation Helicopters
Posted Date: 2021-10-18T04:00Z

[Federal Register Volume 86, Number 198 (Monday, October 18, 2021)]
[Rules and Regulations]
[Pages 57555-57558]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-22464]

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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; 
Amendment 39-21735; AD 2021-19-17]
RIN 2120-AA64

Airworthiness Directives; Sikorsky Aircraft Corporation 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Sikorsky Aircraft Corporation (Sikorsky) Model S-92A 
helicopters. This AD was prompted by an incident of a side facing 
utility seat detaching from wall attachment points. This AD requires 
modifying certain side facing utility seats and observer seats, and 
prohibits installing those seats unless the modification has been 
accomplished. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective November 22, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of November 22, 
2021.

ADDRESSES: For Martin-Baker and Sikorsky service information identified 
in this final rule, 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 [email protected]. 
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. It is also available 
at https://www.regulations.gov by searching for and locating Docket No. 
FAA-2021-0106.

[[Page 57556]]

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 final rule, 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.

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: 
[email protected].

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 Sikorsky Model S-92A 
helicopters with certain Martin-Baker side facing utility or observer 
seats installed. The NPRM published in the Federal Register on March 4, 
2021 (86 FR 12550). The NPRM 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. In 
the NPRM, the FAA proposed to require replacing the main back tube 
assembly in affected side facing utility and observer seats. The NPRM 
also proposed to prohibit installing those seats unless the main back 
tube assembly has been replaced. The FAA is issuing this AD to address 
the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from two commenters. One commenter 
supported the NPRM without change. Sikorsky also commented on the NPRM. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Change the AD to an Appliance AD Against Martin-Baker Seats

    Sikorsky requested changes throughout the proposed AD to change it 
from an aircraft AD against Sikorsky to an appliance AD against Martin-
Baker. Sikorsky stated that the defect is in Martin-Baker technical 
standard order (TSO) authorization seats and is not a defect of the 
Sikorsky Model S-92A helicopter, and that the seats sold to Sikorsky 
are manufactured under TSO-C39b (side facing utility seat) and TSO-
C127a (observer seat) qualifications and are supplied with a TSO-C39b 
or TSO-C127a tag, as applicable. Sikorsky stated that the background of 
the AD should provide the result of the FAA's review with Martin-Baker 
Aircraft. According to Sikorsky, Martin-Baker indicated that seats for 
Sikorsky platforms are tracked separately from other platforms; and 
accordingly, the AD should be issued against affected Martin-Baker 
seats to ensure all affected parts (Martin-Baker seat tube part number 
(P/N) MBCS4109 and/or seat P/Ns MBCS12410AA001, MBCS12200, MBCS7301-2, 
and other P/Ns as identified by Martin-Baker) are corrected. Sikorsky 
further stated that during the review in support of the issuance of 
Sikorsky S-92A Helicopter Alert Service Bulletin ASB 92-25-026, Basic 
Issue, dated March 5, 2020 (ASB 92-25-026), Martin Baker Aircraft 
Company indicated that over 1,000 fielded seats are affected by the 
defect and that Sikorsky purchased 371 of the affected seats for the 
Model S-92A helicopter. Sikorsky stated that it issued ASB 92-25-026 to 
ensure its operators implemented the repairs specified in Martin-Baker 
Special Information Leaflet (SIL) No. 831, dated July 10, 2019 (SIL 
831), and SIL No. 833, dated July 11, 2019 (SIL 833). Additionally, 
Sikorsky explained that ASB 92-25-026 identifies Model S-92A 
helicopters with certain serial numbers (S/Ns) in its Effectivity 
paragraph because that was the known span at the time of its issuance; 
however, the AD should be against the seats because the seats can be 
moved from one serial-numbered aircraft to another serial-numbered 
aircraft and because the required change is to the articles.
    The FAA disagrees. The FAA has confirmed that the manufacturing 
defect of Martin-Baker side facing utility seats supplier P/N 
MBCS12410AA001 did not cause non-compliance with TSO-C39b Aircraft 
Seats and Berths. The unsafe condition does not exist in those seats, 
it resulted from the installation of those seats in Sikorsky Model S-
92A helicopters. In this situation, it became Sikorsky's responsibility 
to show compliance with 14 CFR 29.562 at Amendment 29-41 for the 
installed seat because this is part of the certification basis of the 
aircraft as defined in FAA Type Certificate No. R00024BO. Even though 
the seat is TSO-C39b qualified, the seat installation is required to 
meet the dynamic landing conditions defined in 14 CFR 29.562. Because 
the manufacturing defect caused non-compliance with the aircraft 
certification basis of 14 CFR 29.562, the AD is applicable to the 
aircraft. Conversely, the FAA has confirmed that the manufacturing 
defect of Martin-Baker observer seats supplier P/Ns MBCS12200 and 
MBCS7301-2 did cause non-compliance with TSO-C127a, Rotorcraft, 
Transport Airplane, and Normal and Utility Airplane Seating Systems 
standards, which was the applicable TSO when the seats were 
manufactured. In this situation, the unsafe condition exists in those 
European State of Design seats, and not from the installation of those 
seats in Sikorsky Model S-92A helicopters. The FAA recognizes that in 
this situation, the FAA customarily issues an AD against the appliance 
instead of the aircraft. However, Sikorsky Model S-92A helicopters are 
the only model on the U.S. registry with those seats installed and the 
FAA has therefore determined that it is unnecessary to change this AD 
at this time and have a separate appliance AD against the observer 
seats. If additional information is later identified, the FAA might 
consider further rulemaking.

Request To Change the Consequences of Not Addressing the Unsafe 
Condition

    Sikorsky requested revising the consequences of not addressing the 
unsafe condition in paragraph (e) of this AD to not limit excessive 
lumbar loads during a crash event to just the observer seats because 
any seat with an improperly manufactured main back tube could induce 
excessive lumbar loads during a crash event.
    The FAA agrees for the reasons provided. The FAA has revised 
paragraph (e) of this AD accordingly.

Request for Credit for Compliance With Service Information

    In a request to change requirements proposed in the NPRM, Sikorsky 
commented that compliance with ASB 92-25-026 was required by March 5, 
2021, and that all affected seats (installed on Sikorsky Model S-92A 
helicopters) that have been updated with its procedures should be 
identified as complying with this AD with no further action required.
    The FAA disagrees. This AD requires replacing each main back tube 
assembly by following procedures in ASB 92-25-026. If this action has 
been accomplished prior to the effective date of this AD, then 
compliance for this

[[Page 57557]]

action has been accomplished by paragraph (f) of this AD. However, this 
AD also prohibits installing an affected seat on Sikorsky Model S-92A 
helicopters unless the main back tube assembly has been replaced 
following those procedures in ASB 92-25-026. Additionally, not all 
operators are required to accomplish a manufacturer's maintenance 
procedures. In order for procedures in service information, including 
procedures in alert service bulletins, to become mandatory when the FAA 
has determined the procedures are necessary to correct an identified 
unsafe condition, the FAA must issue an AD.

Request To Require Destruction and Discarding of Parts Instead of 
Removal From Service

    Sikorsky requested changing the requirement to remove certain 
previously-installed parts from service to destroying or discarding 
those parts instead because Sikorsky does not endorse removal from 
service.
    The FAA disagrees. The FAA appreciates that the removed main back 
tube assemblies, split pins, and tie down straps must not be 
reinstalled and that those parts may be destroyed or discarded; 
however, the FAA cannot mandate or enforce destruction or disposal of 
parts to address an unsafe condition. For the purposes of an AD, the 
FAA requires removal from service instead to prevent reinstallation.

Conclusion

    The FAA reviewed the relevant data, considered any 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 these products. Except for a minor change in paragraph (e) 
of this AD to clarify that the FAA is issuing this AD to detect and 
address a main back tube that does not meet design specifications, a 
minor change in Note 3 to paragraph (c) to clarify that the marking of, 
``SIL833 incorporated'' could be located adjacent to identification 
labels on the underside of the sitting platform assembly P/N MBCS12215, 
and any other changes described previously, this AD is adopted as 
proposed in the NPRM. None of the changes will increase the economic 
burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed ASB 92-25-026, with attachments Martin-Baker SIL 
831 and Martin-Baker SIL 833. ASB 92-25-026 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. ASB 92-25-026 
specifies removing existing placards, complying with the applicable 
SIL, reinstalling the removed placards, inspecting for foreign object 
debris (FOD), and cleaning. Martin-Baker SIL 831 for side facing 
utility seat supplier P/N MBCS12410AA001, and Martin-Baker SIL 833 for 
observer seat supplier P/N MBCS12200 and MBCS7301-2, specify 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 ASB 
92-25-026.
    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.

Differences Between This AD and the Service Information

    ASB 92-25-026 specifies a compliance time of no later than March 5, 
2021; whereas this AD specifies a compliance time of within 125 hours 
time-in-service (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 AD does not. SIL 831 and SIL 833 specify 
destroying and disposing discrepant main back tube assemblies and 
discarding removed split pins and tie down straps; whereas this AD 
requires removing those parts from service instead. The service 
information specifies recording compliance; whereas this AD does not.

Costs of Compliance

    The FAA estimates that this AD affects 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 AD.
    Replacing a main back tube assembly takes about 2 work-hours and 
parts cost about $11,217, for an estimated cost of about $11,387 per 
seat. Each helicopter could have up to 19 affected seats, which takes 
up to about 38 work-hours and parts 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 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

    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

0
1. The authority citation for part 39 continues to read as follows:

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

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

[[Page 57558]]

2021-19-17 Sikorsky Aircraft Corporation: Amendment 39-21735; Docket 
No. FAA-2021-0106; Project Identifier AD-2020-00708-R.

(a) Effective Date

    This airworthiness directive (AD) is effective November 22, 
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 ASB 92-25-026, 
Basic Issue, 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 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 or MBCS12215, respectively.

(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 
specifications. 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 during a crash event, and 
subsequent excessive 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) of this AD 
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) 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

    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: [email protected].

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Sikorsky S-92A Helicopter Alert Service Bulletin ASB 92-25-
026, Basic Issue, dated March 5, 2020, with attachments:
    (A) Martin-Baker Special Information Leaflet (SIL) No. 831, 
dated July 10, 2019; and
    (B) Martin-Baker SIL No. 833, dated July 11, 2019.
    (ii) [Reserved]
    (3) As the design approval holder for the product identified in 
paragraph (c) of this AD, contact Sikorsky Aircraft Corporation for 
Martin-Baker service information, as well as Sikorsky S-92A 
helicopter service information identified in this AD, by contacting 
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 [email protected]. Operators 
may also log on to the Sikorsky 360 website at https://www.sikorsky360.com.
    (4) You may view this service information at 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on September 8, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-22464 Filed 10-15-21; 8:45 am]
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