[Federal Register Volume 79, Number 105 (Monday, June 2, 2014)]
[Proposed Rules]
[Pages 31231-31233]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-12738]


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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]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
(Sikorsky) Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
Sikorsky Model S-76A, S-76B, and S-76C helicopters with a main gearbox 
(MGB) installed that has undergone certain repairs. This proposed AD 
would require inspecting the MGB lower housing jet bores for leaks, 
paint or caulk blistering, and liner protrusion. This proposed AD is 
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 proposed actions are intended to prevent failure of the 
MGB from loss of oil, which could result in subsequent loss of control 
of the helicopter.

DATES: We must receive comments on this proposed AD by August 1, 2014.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Fax: 202-493-2251.
     Mail: Send comments to the U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
     Hand Delivery: Deliver to the ``Mail'' address between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov 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 proposed AD, the economic 
evaluation, any comments received, and other information. The street 
address for the Docket Operations Office (telephone 800-647-5527) is in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.
    For service information identified in this proposed AD, contact 
Sikorsky Aircraft Corporation, Customer Service Engineering, 124 Quarry 
Road, Trumbull, CT 06611; telephone 1-800-Winged-S or 203-416-4299; 
email [email protected]. You may review the referenced service 
information at the FAA, Office of the Regional Counsel, Southwest 
Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Jeffrey Lee, Aviation Safety Engineer, 
Boston Aircraft Certification Office, Engine & Propeller Directorate, 
12 New England Executive Park, Burlington, Massachusetts 01803; 
telephone (781) 238-7161; email [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to participate in this rulemaking by submitting 
written comments, data, or views. We also invite comments relating to 
the economic, environmental, energy, or federalism impacts that might 
result from adopting the proposals in this document. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should send only one copy of written comments, or if comments are filed 
electronically, commenters should submit only one time.
    We will file in the docket all comments that we receive, as well as 
a report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. Before acting on this proposal, we 
will consider all comments we receive on or before the closing date for 
comments. We will consider comments filed after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

Discussion

    We have received 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, that have been 
repaired in accordance with Sikorsky Overhaul and Repair Instruction 
(ORI) No. 76350-065, Revisions A through E. Two of the protruding 
liners were discovered following low MGB oil pressure warnings, and two 
were discovered on the same MGB during maintenance. Subsequent 
investigation revealed that 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. The investigation 
determined that the ORI instructions 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

[[Page 31232]]

helicopter. Sikorksy ORI No. 76350-065, Revision F, dated May 10, 2012 
(ORI 76350-065F), resolves this condition by clarifying the wall 
thickness limitations, specifying additional retaining pins for some 
jet bores, and providing additional information to perform the repair 
procedures.

FAA's Determination

    We are proposing this AD because we evaluated all known relevant 
information and determined that an unsafe condition exists and is 
likely to exist or develop on other products of these same type 
designs.

Related Service Information

    Sikorsky has 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 number 76350-065. An MGB that has been repaired in accordance 
with ORI number 76350-065 may be marked TS-065-II, TS-065-IIA, TS-065-
2, or TS-065-2A, depending on the ORI revision used. 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 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.
    Sikorsky ORI 76350-065F describes procedures for repairing the 
retaining ring groove areas of the MGB jet bores. ORI 76350-065F also 
contains clarified housing wall thickness limits for installing jet 
bore liners and procedures for installing additional retaining pins in 
the jet bore liners.

Proposed AD Requirements

    This proposed AD would require, within 50 hours time-in-service 
(TIS), compliance with the inspection requirements of the 
manufacturer's service bulletin. If there is oil leakage or protrusion 
of a jet bore liner, this proposed AD would require replacing the MGB 
before further flight.
    Within 1,500 hours TIS, this proposed AD would require replacing 
the MGB with an MGB that is not subject to the applicability of this 
proposed AD unless it has been repaired in accordance with ORI 76350-
065F.

Differences Between This Proposed AD and the Service Information

    The ASB specifies compliance by a specific calendar date, while the 
compliance time in this proposed AD is in hours TIS. The ASB does not 
specify a terminating action for the recurring inspections of the MGB 
jet bores; the proposed AD would require installing an MGB not subject 
to the applicability of the proposed AD unless it has been repaired in 
accordance with ORI 76350-065F, which would be terminating action for 
the daily inspections. The service information also allows any affected 
MGB sent in for repair or overhaul to be repaired in accordance with 
ORI 76350-065 Revision B or later; the proposed AD would not allow 
installation of an affected MGB unless it has been repaired in 
accordance with ORI 76350-065F, as this revision incorporates the 
clarified instructions and additional retaining pin requirements that 
would provide terminating action for the daily inspections.

Costs of Compliance

    We estimate that this proposed AD would affect 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 
hour, inspecting the jet bore liners would require 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 would require about 14 work-hours, and required parts would 
cost $200, for a cost per helicopter of $1,390. If required, replacing 
the MGB would require about 134 work-hours, and required parts would 
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 proposed 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

    We 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, I certify this proposed regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 proposed 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.

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

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):

Sikorsky Aircraft Corporation (Sikorsky): Docket No. 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

[[Page 31233]]

repaired in accordance with Sikorsky Overhaul and Repair Instruction 
(ORI) No. 76350-065, Revision A through Revision E, 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) Comments Due Date

    We must receive comments by August 1, 2014.

(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 Action

    (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 Sikorsky ORI No. 76350-065, Revision A through 
Revision E, unless it has been subsequently repaired in accordance 
with Sikorsky ORI No. 76350-065, Revision F, dated May 10, 2012.
    (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 Sikorsky ORI 
No. 76350-065, Revision A through Revision E, unless it has been 
subsequently repaired in accordance with Sikorsky ORI No. 76350-065, 
Revision F.
    (2) Within 1500 hours TIS, replace the MGB with an MGB that has 
not been repaired in accordance with Sikorsky ORI No. 76350-065, 
Revision A through Revision E, unless it has been subsequently 
repaired in accordance with Sikorsky ORI No. 76350-065, Revision F. 
This is terminating action for the repetitive inspections required 
by this AD.

(f) Alternative Methods of Compliance (AMOC)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Jeffrey Lee, 
Aviation Safety Engineer, Boston Aircraft Certification Office, 
Engine & Propeller Directorate, 12 New England Executive Park, 
Burlington, Massachusetts 01803; telephone (781) 238-7161; 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.

(h) Additional Information

    Sikorsky Overhaul and Repair Instruction No. 76350-065, Revision 
F, dated May 10, 2012, which is not incorporated by reference, 
contains additional information about the subject of this AD. You 
may review copies of information at the FAA, Office of the Regional 
Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas 76137. For information on the availability of this material at 
the FAA, call (817) 222-5110.

(i) Subject

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

    Issued in Fort Worth, Texas, on May 21, 2014.
Lance T. Gant,
Acting Directorate Manager, Rotorcraft Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-12738 Filed 5-30-14; 8:45 am]
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