AD 2011-12-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-92A | Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters |
Unsafe Condition
Crack found on the MGB upper housing assembly left mounting foot forward rib that cannot be detected visually, potentially leading to loss of the MGB and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Eddy current or fluorescent penetrant inspection (FPI) of each MGB upper housing assembly rib on the left, right, and forward MGB mounting foot at specified intervals based on MGB upper housing assembly hours time-in-service (TIS). If a crack is found, replace the MGB upper housing assembly with an airworthy one.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within specified intervals based on MGB upper housing assembly hours TIS.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Corporation Model S-92A helicopters with main gearbox (MGB) upper housing assembly.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
We are adopting a new airworthiness directive (AD) for the Sikorsky Model S-92A helicopters. This AD requires a nondestructive inspection (NDI), eddy current or fluorescent penetrant inspection (FPI), of each main gearbox (MGB) upper housing assembly rib on the left, right, and forward MGB mounting foot at specified intervals based on the MGB upper housing assembly hours time-in-service (TIS). If there is a crack, this AD requires replacing the MGB upper housing assembly with an airworthy MGB upper housing assembly. This AD is prompted by a report of a crack found on the MGB upper housing assembly left mounting foot forward rib that cannot be detected visually. We are issuing this AD to prevent loss of the MGB and subsequent loss of control of the helicopter.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 76, Number 106 (Thursday, June 2, 2011)]
[Rules and Regulations]
[Pages 31796-31798]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2011-13531]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2011-0548; Directorate Identifier 2011-SW-025-AD;
Amendment 39-16710; AD 2011-12-03]
RIN 2120-AA64
Airworthiness Directives; Sikorsky Aircraft Corporation
(Sikorsky) Model S-92A Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: We are adopting a new airworthiness directive (AD) for the
Sikorsky Model S-92A helicopters. This AD requires a nondestructive
inspection (NDI), eddy current or fluorescent penetrant inspection
(FPI), of each main gearbox (MGB) upper housing assembly rib on the
left, right, and forward MGB mounting foot at specified intervals based
on the MGB upper housing assembly hours time-in-service (TIS). If there
is a crack, this AD requires replacing the MGB upper housing assembly
with an airworthy MGB upper housing assembly. This AD is prompted by a
report of a crack found on the MGB upper housing assembly left mounting
foot forward rib that cannot be detected visually. We are issuing this
AD to prevent loss of the MGB and subsequent loss of control of the
helicopter.
DATES: This AD is effective June 17, 2011.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in the AD as of June 17,
2011.
We must receive comments on this AD by August 1, 2011.
ADDRESSES: You may send comments by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://www.regulations.gov">http://www.regulations.gov</a>. Follow the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> Mail: U.S. Department of Transportation, Docket
Operations, West Building Ground Floor, Room W12-140, 1200 New Jersey
Avenue, SE., Washington, DC 20590.
<bullet> Hand Delivery: U.S. Department of Transportation, Docket
Operations, West Building Ground Floor, Room W12-140, 1200 New Jersey
Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
For service information identified in this AD, contact Sikorsky
Aircraft Corporation, Attn: Manager, Commercial Technical Support,
mailstop S581A, 6900 Main Street, Stratford, CT, telephone (203) 383-
4866, e-mail address <a href="/cdn-cgi/l/email-protection#b9cdcacad5d0dbcbd8cbc0f9cad0d2d6cbcad2c097dad6d4"><span class="__cf_email__" data-cfemail="631710100f0a011102111a23100a080c1110081a4d000c0e">[email protected]</span></a>, or at <a href="http://www.sikorsky.com">http://www.sikorsky.com</a>.
Examining the AD Docket
You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a> or in person at the Docket Operations office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The street address for
the Docket Operations office (telephone: 800-647-5527) is in the
ADDRESSES
[[Page 31797]]
section. Comments will be available in the AD docket shortly after
receipt.
FOR FURTHER INFORMATION CONTACT: Michael Schwetz, Aviation Safety
Engineer, Boston Aircraft Certification Office, 12 New England
Executive Park, Burlington, MA 01803, telephone (781) 238-7761, fax
(781) 238-7170, <a href="/cdn-cgi/l/email-protection#8cc1e5efe4ede9e0a2dfefe4fbe9f8f6cceaededa2ebe3fa"><span class="__cf_email__" data-cfemail="014c68626960646d2f5262697664757b416760602f666e77">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Discussion
We are adopting a new AD for the Sikorsky Model S-92A helicopters.
This AD requires an NDI, eddy current or FPI, of each MGB upper housing
assembly rib on the left, right, and forward MGB mounting foot for a
crack because it cannot be detected visually. This AD is prompted by a
report of a crack found on the MGB upper housing assembly left mounting
foot forward rib during removal of an MGB that had reached its life
limit of 1,000 hours TIS. The MGB mounting foot has a history of two
types of cracks. The visual inspection for these two types of cracks is
required in AD 2010-24-04 (75 FR 70812, November 19, 2010). The
discovery of a third type of crack on the left mounting foot forward
rib may not be reliably detected by visual inspection. This condition,
if not detected and corrected, could result in loss of the MGB, and
subsequent loss of control of the helicopter.
Relevant Service Information
We reviewed Sikorsky Alert Service Bulletin No. 92-63-025A,
Revision A, dated May 12, 2011 (ASB). The ASB specifies a one-time NDI
of the MGB assembly at the mounting foot ribs for cracks.
FAA's Determination
We are issuing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other helicopters of the same type
design.
AD Requirements
This AD requires, at specified intervals based on the MGB upper
housing assembly hours TIS, eddy current or FPI inspecting the left,
right, and forward MGB upper housing mounting foot ribs for a crack. If
there is a crack, the AD requires replacing the MGB upper housing
assembly with an airworthy MGB upper housing assembly. This AD requires
accomplishing the actions by following the specified portions in the
ASB.
Differences Between the AD and the Service Information
We refer to ``flight hours'' as ``hours TIS.'' This AD requires the
inspection to be done by an ASNT Level 2 or equivalent inspector and
this AD requires recurring inspections.
FAA's Justification and Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of
this AD. The FAA has found that the risk to the flying public justifies
waiving notice and comment prior to adoption of this rule because of
the short compliance time required to NDI certain MGB upper housing
assembly mounting foot ribs for a crack. Therefore, we find that notice
and opportunity for prior public comment are impracticable and that
good cause exists for making this amendment effective in less than 30
days.
Comments Invited
This AD is a final rule that involves requirements affecting flight
safety and was not preceded by notice and an opportunity for public
comment. However, we invite you to send any written data, views, or
arguments about this AD. Send your comments to an address listed under
the ADDRESSES section. Include the docket number FAA-2011-0548 and
Directorate Identifier 2011-SW-025-AD at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this AD. We will
consider all comments received by the closing date and may amend this
AD because of those comments.
We will post all comments we receive, without change, to <a href="http://www.regulations.gov">http://www.regulations.gov</a>, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this AD.
Costs of Compliance
We estimate that this AD affects 29 helicopters of U.S. registry.
We estimate the following costs to comply with this AD:
Estimated costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost helicopter operators
----------------------------------------------------------------------------------------------------------------
NDI of each left, right, and 29 helicopters x $286,000 for a MGB $4,760 to do 16 $428,800, assuming
forward MGB mounting foot rib. 3.5 work-hours upper housing. NDI inspections 1 replacement of
per inspection x per year. the MGB upper
16 inspections housing assembly.
per year x $85
per work-hour =
$138,040.
1 x 56 work-hours
x $85 per work-
hour = $4,760, to
replace 1 MGB.
----------------------------------------------------------------------------------------------------------------
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.
We are 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
[[Page 31798]]
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) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979),
(3) Does not warrant making distinction for intrastate aviation in
Alaska, and
(4) 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.
Adoption of 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 (AD):
2011-12-03 Sikorsky Aircraft Corporation (Sikorsky): Amendment 39-
16710; Docket No. FAA-2011-0548; Directorate Identifier 2011-SW-025-
AD.
Effective Date
(a) This AD is effective June 17, 2011.
Affected ADs
(b) None.
Applicability
(c) Model S-92A helicopters with main gearbox (MGB) upper
housing assembly, part number (P/N) 92351-15110-042, -043, -044, -
045, or -046, installed, certificated in any category.
Unsafe Condition
(d) This AD is prompted by a report of a crack found on the MGB
left mounting foot forward rib that may not be found during a visual
inspection. We are issuing this AD to prevent loss of a MGB and
subsequent loss of control of the helicopter.
Compliance
(e) For each MGB upper housing assembly with 700 or more hours
time-in-service (TIS), within 30 hours TIS, unless already done, or
for each MGB upper housing assembly with more than 500 hours TIS but
less than 700 hours TIS, within 50 hours TIS, unless already done,
and for all helicopters thereafter at intervals not to exceed 50
hours TIS:
(1) Clean and Eddy Current inspect the forward, left, and right
MGB mounting foot ribs for a crack by following the Accomplishment
Instructions, paragraphs 3.C. through 3.D.(2)(d), of Sikorsky Alert
Service Bulletin No. 92-63-025A, Revision A, dated May 12, 2011
(ASB); or
(2) Clean and fluorescent penetrant inspect (FPI) the MGB
mounting foot ribs for a crack by following the Accomplishment
Instructions, paragraphs 3.E.(1) through 3.E.(5), of the ASB.
(3) An inspector qualified to ASNT Level II or equivalent is
required to perform the nondestructive inspection (NDI), by Eddy
Current or FPI, of the left, right, and forward MGB mounting foot
ribs for a crack.
(f) If there is a crack, before further flight, replace the MGB
upper housing assembly with an airworthy MGB upper housing assembly.
Note: Sikorsky has developed a Phase III MGB upper housing
assembly, P/N 92351-15310-041, is not subject to the
``Applicability'' of this AD.
Alternative Methods of Compliance (AMOCs)
(g)(1) The Manager, Boston Aircraft Certification Office, 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 ACO, send it to the attention of the
person identified in the Additional Information section of this AD.
(2) Before using any approved AMOC, we request that you notify
your appropriate principal inspector, or lacking a principal
inspector, the manager of the local flight standards district
office/certificate holding district office.
Additional Information
(h) For more information about this AD, contact Michael Schwetz,
Aviation Safety Engineer, Boston Aircraft Certification Office, 12
New England Executive Park, Burlington, MA 01803, telephone (781)
238-7761, fax (781) 238-7170, E-mail <a href="/cdn-cgi/l/email-protection#622f0b010a03070e4c31010a15071618220403034c050d14"><span class="__cf_email__" data-cfemail="afe2c6ccc7cecac381fcccc7d8cadbd5efc9cece81c8c0d9">[email protected]</span></a>.
Material Incorporated by Reference
(i)(1) Inspect the MGB upper housing assembly mounting foot ribs
for a crack by following the specified portions of Sikorsky Alert
Service Bulletin No. 92-63-025A, Revision A, dated May 12, 2011. The
Director of the Federal Register approved the incorporation by
reference of the service information.
(2) For service information identified in this AD, contact
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical
Support, mailstop S581A, 6900 Main Street, Stratford, CT, telephone
(203) 383-4866, e-mail address <a href="/cdn-cgi/l/email-protection#d8acababb4b1baaab9aaa198abb1b3b7aaabb3a1f6bbb7b5"><span class="__cf_email__" data-cfemail="a4d0d7d7c8cdc6d6c5d6dde4d7cdcfcbd6d7cfdd8ac7cbc9">[email protected]</span></a>, or at <a href="http://www.sikorsky.com">http://www.sikorsky.com</a>.
(3) Copies may be inspected at the FAA, Office of the Regional
Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas, or at the National Archives and Records Administration
(NARA). For information on the availability of this material at an
NARA facility, call 202-741-6030, or go to <a href="http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html">http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html</a>.
Subject
(j) The Joint Aircraft System Component (JASC)/Air Transport
Association (ATA) of America Code is 6320 Main Gearbox.
Issued in Fort Worth, Texas on May 24, 2011.
Kim Smith,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2011-13531 Filed 6-1-11; 8:45 am]
BILLING CODE 4910-13-P
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.