Document ID: FAA-2013-0637-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Sikorsky Aircraft Corporation (Sikorsky) Helicopters
Posted Date: 2013-07-23T04:00Z

[Federal Register Volume 78, Number 141 (Tuesday, July 23, 2013)]
[Proposed Rules]
[Pages 44048-44050]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-17631]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0637; Directorate Identifier 2013-SW-030-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 supersede an existing airworthiness directive 
(AD) for Sikorsky Model S-76A, B, and C helicopters. The existing AD 
currently requires inspecting the main rotor lower bifilar arm assembly 
(bifilar arm assembly) for a crack, and if there is a crack, replacing 
the bifilar arm assembly. The AD also requires a one-time test for the 
correct torque on the lug nuts, and if necessary, conducting torque 
stabilization tests. Since we issued that AD, Sikorsky has developed a 
terminating procedure for the inspections required by the existing AD. 
This proposed AD would retain the requirements of that AD, and would 
require replacing the main rotor hub (MRH) pilot with a different part-
numbered MRH pilot, which would be terminating action for the 
requirements of the AD. The proposed actions are intended to prevent 
failure of a bifilar lug, damage to the main rotor control system, and 
subsequent loss of control of the helicopter.

DATES: We must receive comments on this proposed AD by September 23, 
2013.

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, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, CT 06614; 
telephone (800) 562-4409; email tsslibrary@sikorsky.com; or at http://www.sikorsky.com. You may review 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: Nicholas Faust, Aviation Safety 
Engineer, Boston Aircraft Certification Office, Engine & Propeller 
Directorate, 12 New England Executive Park, Burlington, Massachusetts 
01803; telephone (781) 238-7763; email nicholas.faust@faa.gov.

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

    On October 26, 2005, we issued AD 2005-22-01, amendment 39-14345 
(70 FR 61721) for Sikorsky Model S-76A, B, and C helicopters with an 
MRH pilot part number (P/N) 76103-08003-101 with 1,500 or more hours 
time-in-service (TIS) installed. The AD requires, every 50 hours TIS, 
inspecting the main rotor lower bifilar arm assembly in the attachment 
area around the lower bifilar lugs for a crack. If there is a crack, 
the AD requires replacing the bifilar arm assembly. If there is not a 
crack, the AD requires a one-time test for the correct torque on the 
lug nuts, and if necessary, conducting torque stabilization tests. The 
AD was prompted by four reports

[[Page 44049]]

of cracked bifilars. Those actions were intended to prevent failure of 
a bifilar lug, damage to the main rotor control system, and subsequent 
loss of control of the helicopter.

Actions Since Existing AD Was Issued

    Since we issued AD 2005-22-01, Sikorsky issued Alert Service 
Bulletin 76-65-65, dated March 22, 2012 (ASB 76-65-65). ASB 76-65-65 
specifies measuring the MRH diameter and, if the diameter is small, 
replacing the MRH pilot with a newly-redesigned MRH pilot. The new MRH 
pilot has a larger flange diameter that provides greater support for 
the bifilar assembly and reduces stress on the bifilar assembly 
attachment lugs. We propose to supersede AD 2005-22-01 to require 
installation of the large diameter MRH pilot as terminating action for 
the repetitive inspection requirements. These actions are intended to 
prevent failure of a bifilar lug, damage to the main rotor control 
system, and subsequent loss of control of the helicopter.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Related Service Information

    Sikorsky issued S-76 Alert Service Bulletin (ASB) 76-65-62, dated 
December 14, 2004 (ASB 76-65-62), which describes procedures to inspect 
the lower bifilar assembly for a crack. We have also reviewed ASB 76-
65-65, which specifies measuring the MRH diameter and, if the diameter 
is small, replacing the MRH pilot with a newly-redesigned MRH pilot 
with a larger flange diameter.

Proposed AD Requirements

    This proposed AD would retain the repetitive inspection 
requirements of AD 2005-22-01, but would also require replacing the MRH 
pilot, P/N 76103-08003-101, with MRH pilot, P/N 76103-08003-102, as 
terminating action.

Costs of Compliance

    We estimate that this proposed AD would affect 181 helicopters of 
U.S. Registry.
    We estimate that operators may incur the following costs in order 
to comply with this AD. Inspecting the bifilar arm assembly would 
require about 4 work-hours, at an average labor rate of $85 per hour, 
for a cost per helicopter of $340 and a total cost to U.S. operators of 
$61,540.
    Replacing a cracked bifilar arm assembly would require about 4 
work-hours, at an average labor rate of $85 per hour, and required 
parts would cost about $19,727, for a cost per helicopter of $20,067.
    Replacing the MRH pilot, P/N 76103-08003-101, with an MRH pilot, P/
N 76103-08003-102, would require about 0.7 work-hour, at an average 
labor rate of $85 per hour, and required parts would cost about $1,043, 
for a cost per helicopter of $1,103 and a total cost to U.S. operators 
of $199,643.

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 removing Airworthiness Directive (AD) 
2005-22-01, Amendment 39-14345 (70 FR 61721, October 26, 2005), and 
adding the following new AD:

Sikorsky Aircraft Corporation: Docket No. FAA-2013-0637; Directorate 
Identifier 2013-SW-030-AD.

(a) Applicability

    This AD applies to Model S-76A, B, and C helicopters with a main 
rotor hub (MRH) pilot, part number (P/N) 76103-08003-101, installed, 
certificated in any category.

(b) Unsafe Condition

    This AD defines the unsafe condition as a crack on the MRH pilot 
bifilar assembly lug, which could result in failure of a bifilar 
lug, damage to the main rotor system, and subsequent loss of control 
of the helicopter.

 (c) Affected ADs

    This AD supersedes AD 2005-22-01, Amendment 39-14345 (70 FR 
61721, October 26, 2005).

(d) Comments Due Date

    We must receive comments by September 23, 2013.

(e) 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.

(f) Required Actions

    (1) For MRH pilots with 1,500 or more hours time-in-service 
(TIS), within 50 hours TIS, and thereafter at intervals not to 
exceed 50 hours TIS, inspect the lower bifilar arm assembly for a 
crack in the lug attachment area. Conduct the inspection of the 
lower bifilar arm assembly by following the Accomplishment 
Instructions, paragraph 3.A.(1) through 3.A.(6), of Sikorsky Alert 
Service Bulletin No. 76-65-62, dated December 14, 2004 (ASB 76-65-
62).

[[Page 44050]]

    (i) If there is a crack on any bifilar assembly arm lug, before 
further flight, replace the bifilar arm assembly with an airworthy 
bifilar arm assembly.
    (ii) If no crack is found at the initial inspection, perform a 
one-time torque test. Perform the torque test and the additional 
torque procedures as stated in the Accomplishment Instructions, 
paragraph 3.B.(1) through 3.B.(3), of ASB 76-65-62. The torque test 
is not required at the recurring inspection intervals of the lower 
bifilar arm assembly.
    (iii) Within 600 hours TIS, replace the MRH pilot, P/N 76103-
08003-101, with an MRH pilot, P/N 76103-08003-102.
    (2) For MRH pilots with less than 900 hours TIS, prior to 
accumulating 1,500 hours TIS, replace the MRH pilot, P/N 76103-
08003-101, with a MRH pilot, P/N 76103-08003-102.
    (3) After the effective date of this AD, do not install an MRH 
pilot, P/N 76103-08003-101, on any helicopter.

(g) Special Flight Permit

    Special flight permits will not be issued.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Nicholas Faust, 
Aviation Safety Engineer, Boston Aircraft Certification Office, 
Engine & Propeller Directorate, 12 New England Executive Park, 
Burlington, Massachusetts 01803; telephone (781) 238-7763; email 
nicholas.faust@faa.gov.
    (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.

(i) Additional Information

    For service information identified in this AD, contact Sikorsky 
Aircraft Corporation, Attn: Manager, Commercial Technical Support, 
mailstop s581a, 6900 Main Street, Stratford, CT 06614; telephone 
(800) 562-4409; email tsslibrary@sikorsky.com; or at http://www.sikorsky.com. You may review the service information at the FAA, 
Office of the Regional Counsel, Southwest Region, 2601 Meacham 
Blvd., Room 663, Fort Worth, Texas 76137.

(j) Subject

    Joint Aircraft Service Component (JASC) Code: 6220: Main Rotor 
Head.

    Issued in Fort Worth, Texas, on July 11, 2013.
Kim Smith,
Directorate Manager, Rotorcraft Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-17631 Filed 7-22-13; 8:45 am]
BILLING CODE 4910-13-P