Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

[Federal Register Volume 81, Number 2 (Tuesday, January 5, 2016)]
[Rules and Regulations]
[Pages 147-150]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-33013]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2014-0335; Directorate Identifier 2013-SW-021-AD; 
Amendment 39-18358; AD 2015-26-10]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, S-76B, and S-76C 
helicopters. This AD requires inspecting the main gearbox (MGB) lower 
housing jet bores for leaks, paint or caulk blistering, and liner 
protrusion. This AD was prompted by several reports of MGB low oil 
pressure warnings which were determined to be the result of unsecured 
jet bore liners that had protruded. The actions are intended to prevent 
failure of the MGB from loss of oil, which could result in subsequent 
loss of control of the helicopter.

[[Page 148]]


DATES: This AD is effective February 9, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of a certain document listed in this AD as of February 9, 
2016.

ADDRESSES: For service information identified in this final rule, 
contact Sikorsky Aircraft Corporation, Customer Service Engineering, 
124 Quarry Road, Trumbull, Connecticut 06611; telephone 1-800-Winged-S 
or 203-416-4299; email [email protected]. You may review a copy 
of the referenced service information at the FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, 
Fort Worth, Texas 76177.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for or locating Docket No. FAA-2014-
0335; 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, any incorporated-by-reference service information, 
the economic evaluation, any comments received, and other information. 
The street address for the Docket Operations Office (phone: 800-647-
5527) is U.S. Department of Transportation, Docket Operations Office, 
M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Kirk Gustafson, Aviation Safety 
Engineer, Boston Aircraft Certification Office, Engine & Propeller 
Directorate, 12 New England Executive Park, Burlington, Massachusetts 
01803; telephone (781) 238-7190; email [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    On June 2, 2014, at 79 FR 31231, the Federal Register published our 
notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR 
part 39 by adding an AD that would apply to Sikorsky Model S-76A, S-
76B, and S-76C helicopters with a MGB installed that has undergone 
certain repairs. The NPRM proposed to require, within 50 hours time-in-
service (TIS), inspecting the MGB for leaks, paint or caulk blistering, 
and liner protrusion. If there is oil leakage or protrusion of a jet 
bore liner, the NPRM proposed to require replacing the MGB before 
further flight. The NPRM also proposed to require, within 1,500 hours 
TIS, replacing the MGB with an MGB that was not subject to the 
applicability of the NPRM unless it had been repaired in accordance 
with a later overhaul and repair procedure.
    The NPRM was prompted by four reports of protruding jet bore liners 
on Sikorsky S-76 helicopters with a MGB, part number (P/N) 76351-09000 
series, 76351-09500 series, and 76351-09600 series. During an overhaul 
of the MGB, the jet bore liner retaining pins were not adequately 
drilled into the liner, allowing the jet bore liner to move in the 
housing, because the overhaul and repair instruction (ORI) did not 
adequately describe procedures and housing wall thickness limitations 
for installing the retaining pins. Movement of the jet bore liner into 
the housing allows oil to leak between the liner and the housing, 
possibly resulting in loss of oil in the MGB, which could result in 
failure of the MGB and subsequent loss of control of the helicopter.
    At the time we issued the NPRM, we understood these repairs had 
been made in accordance with Sikorsky ORI No. 76350-065, Revisions A 
through E. However, the incident MGBs had only been repaired in 
accordance with Sikorsky ORI No. 76350-065, Revision A or earlier. 
Sikorsky ORI 76350-065, Revisions B through F, resolve the unsafe 
condition by clarifying the retaining pin installation instructions. 
This AD now reflects that clarification.

Comments

    After our NPRM (79 FR 31231, June 2, 2014) was published, we 
received comments from one commenter.

Request

    Sikorsky stated the proposed requirement to overhaul the affected 
MGBs within 1,500 hours TIS is overly conservative because the daily 
visual inspection is adequate to ensure safety until the next overhaul 
period. Sikorsky further commented that the 1,500 hour compliance time 
would be burdensome to operators and not cost effective. When asked for 
additional information to support this comment, Sikorsky stated that 
its maintenance program has a major inspection, and not a MGB overhaul, 
every 1,500 hours. The major inspection does not require removal of the 
MGB. Overhaul of the MGB for Model S76A helicopters occurs every 3,250 
hours and for Model S76B/C helicopters occurs every 3,750 hours.
    We agree. We intended the proposed requirement to provide a 
terminating action that coincides with overhaul of the MGB. We 
incorrectly understood the 1,500-hour major inspection involved 
removing the MGB from the helicopter. We agree that due to the gradual 
loss of oil, safety is maintained with the repetitive inspections until 
the MGB is replaced or overhauled when specified in the maintenance 
program. We have revised paragraph (e)(2) of this AD to require 
replacement of the MGB ``within 3,750 hours TIS'' instead of ``within 
1,500 hours TIS.''
    Sikorsky also commented that limiting acceptable repairs to those 
performed in accordance with Sikorksy ORI 76350-065 Revision F was 
unnecessary because Revision B and subsequent revisions provide 
installation details that are structurally equivalent to Revision F. 
When asked for additional information to support this comment, Sikorsky 
stated the changes in Revision B clarified the pin retention 
instructions sufficiently to resolve the oil leakage issue. Although 
Revision F provides for the installation of an additional pin, Sikorsky 
stated that this is not a significant change. Sikorsky confirmed that 
all reports of oil leakage involved repairs using the procedures in 
Revision A or earlier.
    We agree. We reexamined Sikorsky ORI No. 76350-065 and its 
revisions and found Revisions B through F structurally equivalent with 
only minor changes and improvements. We have changed paragraphs (a) and 
(e) of this AD to reference the appropriate revisions of Sikorsky ORI 
No. 76350-065.

FAA's Determination

    We have reviewed the relevant information, considered the comments 
received, and determined that an unsafe condition exists and is likely 
to exist or develop on other products of these same type designs and 
that air safety and the public interest require adopting the AD 
requirements as proposed with the changes described previously. These 
changes are consistent with the intent of the proposals in the NPRM (79 
FR 31231, June 2, 2014), and will not increase the economic burden on 
any operator nor increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    Sikorsky issued Alert Service Bulletin (ASB) 76-66-50, Basic Issue, 
dated January 14, 2013 (ASB 76-66-50) for Model S-76A, S-76B, and S-76C 
helicopters with an MGB P/N 76351-09000 series, 76351-09500 series, and 
76351-09600 series, which have been repaired in accordance with ORI No. 
76350-065 or ORI No. 76350-065, Revision A. ASB 76-66-50 describes 
procedures for inspecting each MGB lower housing jet bore for leaking 
oil, paint or caulk blistering, and liner protrusion. If there is any 
liner protrusion or leaking oil between the

[[Page 149]]

liner and the housing, the ASB requires replacing the MGB. If there is 
paint or caulk blistering, the ASB requires further inspecting for 
leaking oil by replacing the jet bore packing, performing a ground run 
of the main rotor for 30 minutes, and re-inspecting the jet bore for 
leaking oil.
    This 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.

Other Related Service Information

    We also reviewed Sikorsky ORI No. 76350-065, Revision B, dated June 
10, 2011; Revision C, dated June 27, 2011; Revision D, dated January 
20, 2012; Revision E, dated January 27, 2012; and Revision F, dated May 
10, 2012. This service information describes procedures for repairing 
the retaining ring groove areas of the MGB jet bores and installing 
retaining pins in the jet bore liners.

Differences Between This AD and the Service Information

    The ASB specifies compliance by a specific calendar date, while the 
compliance time in this AD is in hours TIS. The ASB does not specify a 
terminating action for the recurring inspections of the MGB jet bores; 
while this AD does specify a terminating action for the recurring 
inspections.

Costs of Compliance

    We estimate that this AD affects 53 helicopters of U.S. Registry. 
We estimate that operators may incur the following costs in order to 
comply with this AD. At an average labor rate of $85 per work-hour, 
inspecting the jet bore liners requires about 1.1 work-hours, for a 
cost per helicopter of $94 and a total cost to US operators of $4,982 
per inspection cycle. If required, repairing a jet bore liner requires 
about 14 work-hours, and required parts cost $200, for a cost per 
helicopter of $1,390. If required, replacing the MGB requires about 134 
work-hours, and required parts cost $994,000, for a cost per helicopter 
of $1,005,390.

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 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) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction; 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.
    We prepared an economic evaluation of the estimated costs to comply 
with this AD and placed it in the AD docket.

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):

2015-26-10 Sikorsky Aircraft Corporation (Sikorsky): Amendment 39-
18358; Docket FAA-2014-0335; Directorate Identifier 2013-SW-021-AD.

(a) Applicability

    This AD applies to Sikorsky Model S-76A, S-76B, and S-76C 
helicopters with a main gearbox (MGB) part number (P/N) 76351-09000 
series, 76351-09500 series, and 76351-09600 series installed that 
has been repaired in accordance with Sikorsky Overhaul and Repair 
Instruction (ORI) No. 76350-065, dated November 12, 1982 (ORI 76350-
065), or ORI No. 76350-065, Revision A, dated September 21, 1984 
(ORI 76350-065A), certificated in any category.

(b) Unsafe Condition

    This AD defines the unsafe condition as an unsecured MGB lower 
housing jet bore liner. This condition may cause the liner to move 
out of place, allowing oil to leak from the MGB, resulting in MGB 
failure and subsequent loss of control of the helicopter.

(c) Effective Date

    This AD becomes effective February 9, 2016.

(d) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(e) Required Actions

    (1) Within 50 hours time-in-service (TIS), and thereafter at 
intervals not to exceed 6 hours TIS, inspect each MGB lower housing 
jet bore (jet bore), as depicted in Figures 3 and 4 of Sikorsky S-76 
Alert Service Bulletin 76-66-50, Basic Issue, dated January 14, 2013 
(ASB 76-66-50), for liner protrusion or movement, paint or caulk 
blistering, or oil leakage.
    (i) If there is any liner protrusion or movement, before further 
flight, replace the MGB with an MGB that has not been repaired in 
accordance with ORI 76350-065 or ORI 76350-065A, unless it has been 
subsequently repaired in accordance with Sikorsky ORI No. 76350-065, 
Revision B, dated June 10, 2011 (ORI 76350-065B); Sikorsky ORI No. 
76350-065, Revision C, dated June 27, 2011 (ORI 76350-065C); 
Sikorsky ORI No. 76350-065, Revision D, dated January 20, 2012 (ORI 
76350-065D); Sikorsky ORI No. 76350-065, Revision E, dated January 
27, 2012 (ORI 76350-065E); or Sikorsky ORI No. 76350-065, Revision 
F, dated May 10, 2012 (ORI 76350-065F).
    (ii) If there is any oil leakage or paint or caulk blistering, 
inspect the jet bore for liner protrusion and perform a leakage 
check by following the Accomplishment Instructions, Paragraphs 
3.C.(1) through 3.C.(6)(a), of ASB 76-66-50.
    (iii) If any moisture or droplets of MGB oil are visible on a 
jet bore after accomplishing the leakage check specified in 
paragraph 3.C.(6)(a) of ASB 76-66-50, repeat paragraphs 3.C(4) 
through 3.C(6) of ASB 76-66-50. If any moisture or droplets of MGB 
oil are still visible, before further flight, replace the MGB with 
an MGB that has not been repaired in accordance with ORI 76350-065 
or ORI 76350-065A, unless it has been subsequently repaired in 
accordance with ORI 76350-065B, ORI 76350-065C, ORI 76350-065D, ORI 
76350-065E, or ORI 76350-065F.

[[Page 150]]

    (2) Within 3,750 hours TIS, replace the MGB with an MGB that has 
not been repaired in accordance with ORI 76350-065 or ORI 76350-
065A, unless it has been subsequently repaired in accordance with 
ORI 76350-065B, ORI 76350-065C, ORI 76350-065D, ORI 76350-065E, or 
ORI 76350-065F. This is terminating action for the repetitive 
inspections required by this AD.

(f) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Kirk Gustafson, 
Aviation Safety Engineer, Boston Aircraft Certification Office, 
Engine & Propeller Directorate, 12 New England Executive Park, 
Burlington, Massachusetts 01803; telephone (781) 238-7190; email 
[email protected].
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, we suggest that you 
notify your principal inspector, or lacking a principal inspector, 
the manager of the local flight standards district office or 
certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(g) Additional Information

    Sikorsky Overhaul and Repair Instruction No. 76350-065, dated 
November 12, 1982; Revision A, dated September 21, 1984; Revision B, 
dated June 10, 2011; Revision C, dated June 27, 2011; Revision D, 
dated January 20, 2012; Revision E, dated January 27, 2012; and 
Revision F, dated May 10, 2012, which are not incorporated by 
reference, contain additional information about the subject of this 
AD. You may review a copy of this service information at the FAA, 
Office of the Regional Counsel, Southwest Region, 10101 Hillwood 
Pkwy., Room 6N-321, Fort Worth, Texas 76177.

(h) Subject

    Joint Aircraft Service Component (JASC) Code: 6320, Main Rotor 
Gearbox.

(i) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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-76 Alert Service Bulletin 76-66-50, Basic Issue, 
dated January 14, 2013.
    (ii) Reserved.
    (3) For Sikorsky service information identified in this final 
rule, contact Sikorsky Aircraft Corporation, Customer Service 
Engineering, 124 Quarry Road, Trumbull, Connecticut 06611; telephone 
1-800-Winged-S or 203-416-4299; email [email protected].
    (4) You may view this service information at FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-
321, Fort Worth, Texas 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, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Fort Worth, Texas, on December 23, 2015.
John Hardie,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2015-33013 Filed 1-4-16; 8:45 am]
 BILLING CODE 4910-13-P

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