[Federal Register Volume 72, Number 104 (Thursday, May 31, 2007)]
[Rules and Regulations]
[Pages 30247-30249]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-10126]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28241; Directorate Identifier 2007-SW-07-AD; 
Amendment 39-15062; AD 2007-11-05]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76A, B, and C Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) for 
Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C 
helicopters. This action requires a one-time ultrasonic inspection of 
the main rotor shaft assembly (M/R shaft) for cracking. This amendment 
is prompted by the discovery of cracking that occurred during the 
manufacturing of certain M/R shafts. The actions specified in this AD 
are intended to detect cracking in the M/R shaft, which could result in 
separation of the main rotor and subsequent loss of control of the 
helicopter.

DATES: Effective June 15, 2007.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 15, 2007.
    Comments for inclusion in the Rules Docket must be received on or 
before July 30, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically;
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically;
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, 
Washington, DC 20590;
     Fax: (202) 493-2251; or
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    You may get the service information identified in this AD from 
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, Connecticut, 
phone (203) 383-4866, e-mail address [email protected].
    Examining the Docket: You may examine the docket that contains the 
AD, any comments, and other information on the Internet at http://dms.dot.gov, or in person at the Docket Management System (DMS) Docket 
Offices between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays. The Docket Office (telephone (800) 647-5227) is 
located on the plaza level of the Department of Transportation Nassif 
Building at the street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after the DMS 
receives them.

FOR FURTHER INFORMATION CONTACT: Kirk Gustafson, Aviation Safety 
Engineer, Boston Aircraft Certification Office, Engine and Propeller 
Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803, 
telephone (781) 238-7190, fax (781) 238-7170.

SUPPLEMENTARY INFORMATION: This amendment adopts an AD for Sikorsky 
Model S-76A, B, and C helicopters. This action requires, within 75 
hours time-in-service (TIS), a one-time ultrasonic inspection of the M/
R shaft for cracking. This amendment is prompted by the manufacturer's 
discovery of cracking that occurred during the manufacturing of certain 
M/R shafts. During a heat-treatment process of these M/R shafts, 
inadequate time was allowed for the M/R shafts to cool to a proper 
temperature between the heat-treatment cycles, which reduced the M/R 
shaft's ductility (capability of the M/R shaft being fashioned into a 
new form), and increased the potential for cracking to occur during 
subsequent cold-work forming of the M/R shaft. The actions specified in 
this AD are intended to detect cracking in the M/R shaft, which could 
result in separation of the main rotor and subsequent loss of control 
of the helicopter.
    We have reviewed the following alert service bulletins:
     Sikorsky Alert Service Bulletin (ASB) No. 76-66-45A, 
Revision A, which is applicable to all S-76 model helicopters, with a 
M/R shaft, P/N 76351-09630-041, with certain serial numbers, installed; 
and
     Sikorsky ASB No. 76-66-46, which is applicable to all 
Model S-76A helicopters, with a M/R shaft, P/N 76351-09030-all dash 
numbers, with certain serial numbers, installed. Both ASBs are dated 
February 7, 2007, and both describe a one-time ultrasonic inspection of 
the M/R shaft for cracking, for main gear box (MGB) assemblies 
installed on helicopters, for MGB assemblies not installed on a 
helicopter, and for M/R shafts not installed on MGBs.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, this AD is being issued 
to detect cracking in the M/R shaft, which could result in separation 
of the main rotor and subsequent loss of control of the helicopter. 
This AD requires a one-time ultrasonic inspection of the M/R shaft for 
cracking, instructions for reassembly of the lower bearing housing 
assembly installation of the MGB and performance of a ground run leak 
test. Accomplish the inspection by following specified portions of the 
ASBs described previously. The ultrasonic inspection of the M/R shaft 
must be performed by a Level II or Level III inspector, qualified under 
the guidelines established by MIL-STD-410E, ATA Specification 105, AIA-
NAS-410, or an FAA-accepted equivalent for qualification standards of 
Nondestructive Testing inspection/evaluation personnel. Recurrent 
training

[[Page 30248]]

and examinations are part of the qualification requirements.
    The short compliance time involved is required because the 
previously described critical unsafe condition can adversely affect the 
controllability or structural integrity of the helicopter. The Model S-
76 helicopter fleet is comprised of a large number of aircraft 
operating in an off-shore logistics support role for the petroleum 
industry. As such, many aircraft operate at high utilization rates 
approaching 200 hours TIS per month and this rate could translate to a 
higher potential for cracks that may have formed during manufacturing 
to propagate, leading to failure of the M/R shaft. Therefore, 
performing a one-time ultrasonic inspection of the M/R shaft for 
cracking within 75 hours TIS, which may equate to less than 2 weeks 
time-in-service, along with replacing any cracked M/R shaft with an 
airworthy M/R shaft before further flight, justify issuance of this AD 
immediately.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
    We estimate that this AD will affect 41 M/R shafts--20 M/R shafts 
to be removed from helicopters, 16 M/R shafts to be inspected before 
they are assembled into the MGB for installation on a helicopter, 5 M/R 
shafts that must be removed from a MGB for inspection before 
installation on a helicopter. We estimate that, at a labor rate of $80 
per work hour, it will take approximately:
     100 work hours for the entire fleet of operators to 
determine whether they have an affected M/R shaft;
     For the 20 M/R shafts installed in helicopters--80 work 
hours to remove the MGB and M/R shaft for inspection; 80 work hours to 
reinstall the M/R shaft and MGB; and 12 work hours to return the 
aircraft to service;
     For the 5 M/R shafts installed in a MGB, but not installed 
in a helicopter--2 work hours to remove the M/R shaft from the MGB; and
     4 work hours to ultrasonic inspect each of the 41 M/R 
shafts.
    Also, we estimate that for the 25 M/R shafts that must be removed 
from a MGB for inspection, reassembly will require $100 in consumable 
parts for each MGB. Based on these figures, we estimate that the total 
cost impact of the AD on U.S. operators will be $299,620, assuming that 
operators do not find a M/R shaft with a crack.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any written data, 
views, or arguments regarding this AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2007-28241; 
Directorate Identifier 2007-SW-07-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the AD. We will consider 
all comments received by the closing date and may amend the AD in light 
of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this AD. Using the search function of our docket 
Web site, you can find and read the comments to any of our dockets, 
including the name of the individual who sent the comment. You may 
review the DOT's complete Privacy Act Statement in the Federal Register 
published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Regulatory Findings

    We have determined that 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 the 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); 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.
    We prepared an economic evaluation of the estimated costs to comply 
with this AD. See the DMS to examine the economic evaluation.

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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding a new airworthiness directive to 
read as follows:

2007-11-05 Sikorsky Aircraft Corporation: Amendment 39-15062. Docket 
No. FAA-2007-28241; Directorate Identifier 2007-SW-07-AD.
    Applicability: Model S-76A, B and C helicopters with a main 
rotor shaft assembly (M/R shaft) listed in the following table 
installed, certificated in any category.

------------------------------------------------------------------------
            M/R shaft part No.                       Serial No.
------------------------------------------------------------------------
76351-09030-all dash numbers..............  B015-00782 through B015-
                                             00791; B015-00811 through
                                             B015-00816; E015-00844
                                             through E015-00865; andE015-
                                             00908 through E015-00918.
76351-09630-041...........................  C213-00436 through C213-
                                             00454; D213-00537 through
                                             D213-00545; andD213-00575
                                             through D213-00585.
------------------------------------------------------------------------

    Compliance: Required within 75 hours time-in-service, unless 
accomplished previously.

[[Page 30249]]

    To detect cracking in the M/R shaft, which could result in 
separation of the main rotor and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) Perform a one-time ultrasonic inspection of the M/R shaft 
for cracking in accordance with Nondestructive Testing/Inspection 
Technique, Ultrasonic Technique (UT) Number 5043, latest version. 
The ultrasonic inspection of the M/R shaft must be performed by a 
Level II or Level III inspector, qualified under the guidelines 
established by MIL-STD-410E, ATA Specification 105, AIA-NAS-410, or 
an FAA-accepted equivalent for qualification standards of 
Nondestructive Testing inspection/evaluation personnel. Recurrent 
training and examinations are part of the qualification 
requirements.
    (1) For Model S-76A, B and C helicopters with a M/R shaft, P/N 
76351-09630-041, installed, remove and inspect the M/R shaft in 
accordance with the Accomplishment Instructions, paragraphs 
3.B.(1)(a) through 3.B.(1)(d)5 of Sikorsky Alert Service Bulletin 
(ASB) No. 76-66-45A, Revision A, dated February 7, 2007.
    (2) For Model S-76A helicopters with a M/R shaft, P/N 76351-
09030--all dash numbers, installed, remove and inspect the M/R shaft 
in accordance with the Accomplishment Instructions, paragraphs 
3.B.(1)(a) through 3.B.(1)(d)5 of Sikorsky ASB No. 76-66-46, dated 
February 7, 2007.
    (3) If a crack is found, replace the M/R shaft with an airworthy 
M/R shaft that has been ultrasonically inspected in accordance with 
paragraph (a) of this AD before further flight.
    (4) Reassemble the lower bearing housing assembly, install the 
main gear box, and perform the ground run leak test in accordance 
with the Accomplishment Instructions, paragraphs 3.B.(1)(f) through 
3.B.(1)(l) of either ASB No. 76-66-45A, Revision A or ASB No. 76-66-
46, both dated February 7, 2007, as appropriate for your part-
numbered M/R shaft.
    (b) Before installing an affected M/R shaft, ultrasonically 
inspect the M/R shaft and reassemble the lower bearing housing 
assembly, install the main gear box, and perform the ground run leak 
test in accordance with the requirements of paragraph (a) of this 
AD.
    (c) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Manager, Boston Aircraft Certification Office, FAA, 
ATTN: Kirk Gustafson, Aviation Safety Engineer, 12 New England 
Executive Park, Burlington, MA 01803, telephone (781) 238-7190, fax 
(781) 238-7170, for information about previously approved 
alternative methods of compliance.
    (d) The ultrasonic inspection shall be done in accordance with 
the specified portions of Sikorsky Alert Service Bulletin (ASB) No. 
76-66-45A, Revision A, and Sikorsky ASB No. 76-66-46, both dated 
February 7, 2007. The Director of the Federal Register approved this 
incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51. Copies may be obtained from Sikorsky Aircraft 
Corporation, Attn: Manager, Commercial Technical Support, mailstop 
s581a, 6900 Main Street, Stratford, Connecticut, phone (203) 383-
4866, e-mail address [email protected]. 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 NARA, call (202) 741-6030, 
or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    (e) This amendment becomes effective on June 15, 2007.

    Issued in Fort Worth, Texas, on May 16, 2007.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. E7-10126 Filed 5-30-07; 8:45 am]
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