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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 helicop-
    ters, 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 in-
corporated," 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 al-
    ready 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 in-
    spector, 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:
    dorie.resnik@faa.gov.

(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 in-
    formation identified in this AD,  by  contacting  your  local Sikorsky
    Field Representative or Sikorsky's Service Engineering Group at Sikor-
    sky 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.

(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 refer-
    ence at the National Archives and Records Administration  (NARA).  For
    information on the availability of this material  at NARA,  email: fr.
    inspection@nara.gov,   or   go  to:  https://www.archives.gov/federal-
    register/cfr/ibr-locations.html.

Issued on September 8, 2021.  Lance T. Gant,  Director,  Compliance & Air-
worthiness Division, Aircraft Certification Service.

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.
PREAMBLE 

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.

-----------------------------------------------------------------------

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 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. It is also available
at https://www.regulations.gov by searching for and locating Docket No.
FAA-2021-0106.

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:
dorie.resnik@faa.gov.

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 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


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]

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