Document ID: FAA-2010-0720-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Sikorsky Aircraft Corp. (Sikorsky) Model S-92A Helicopters
Posted Date: 2010-07-21T04:00Z

[Federal Register: July 21, 2010 (Volume 75, Number 139)]
[Proposed Rules]               
[Page 42340-42342]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21jy10-17]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0720; Directorate Identifier 2010-SW-050-AD]
RIN 2120-AA64

 
Airworthiness Directives; Sikorsky Aircraft Corporation 
(Sikorsky) Model S-92A Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes adopting a new airworthiness directive 
(AD) for Sikorsky Model S-92A helicopters. This proposal would require 
revising the airworthiness limitations section of the Instructions

[[Page 42341]]

for Continued Airworthiness (ICA) to reduce the life limit of the main 
gearbox housing and replacing any main gearbox housing that exceeds the 
life limit. This proposal is prompted by a fatigue analysis conducted 
after a helicopter was found with a severed main gearbox mounting foot 
pad (foot pad) that failed due to fatigue. The actions specified by 
this proposed AD are intended to prevent failure of the main gearbox 
mounting housing foot pad, loss of the main gearbox, and subsequent 
loss of control of the helicopter.

DATES: Comments must be received on or before September 20, 2010.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, 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.
    You may examine the comments to this proposed AD in the AD docket 
on the Internet at http://www.regulations.gov.

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.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written data, views, or arguments 
regarding this proposed AD. Send your comments to the address listed 
under the caption ADDRESSES. Include the docket number ``FAA-2010-0720, 
Directorate Identifier 2010-SW-050-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact 
with FAA personnel concerning this proposed rulemaking. 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 or signed 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).

Examining the Docket

    You may examine the docket that contains the proposed AD, any 
comments, and other information in person at the Docket Operations 
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Operations office (telephone (800) 647-5527) is 
located in Room W12-140 on the ground floor of the West Building at the 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.

Discussion

    This document proposes adopting a new AD for Sikorsky Model S-92A 
helicopters. This proposal would require revising the airworthiness 
limitations section of the ICA to reduce the life limit of the main 
gearbox housing from 2700 hours time-in-service (TIS) to 1000 hours TIS 
and to replace any main gearbox housing that exceeds the lower life 
limit. This proposal is prompted by review of a fatigue analysis 
conducted after a helicopter was found with a severed foot pad due to 
the effect of fatigue of the main gearbox housing. This condition, if 
not corrected, could result in failure of the main gearbox housing 
mounting foot pad, loss of the main gearbox, and subsequent loss of 
control of the helicopter.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, the proposed AD would 
require, within 60 days, revising the airworthiness limitations section 
of the ICA to reduce the life limit of the main gearbox housing from 
2700 hours TIS to 1000 hours TIS and replacing, before further flight, 
any main gearbox housing that has exceeded the 1000-hour TIS life 
limit.
    We estimate that this proposed AD would affect 15 helicopters of 
U.S. registry, and the proposed actions would take about 112 work hours 
per helicopter at an average labor rate of $85 per work hour. Required 
parts would cost about $200,000 per helicopter. Based on these figures, 
we estimate the total cost impact of the proposed AD on U.S. operators 
would be $3,142,800, assuming all 15 helicopters replace the main 
gearbox housing.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. Additionally, 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 above, I certify that the 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); 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 a draft economic evaluation of the estimated costs to 
comply with this proposed AD. See the AD docket to examine the draft 
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, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

[[Page 42342]]

PART 39--AIRWORTHINESS DIRECTIVES

    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]

    2. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

Sikorsky Aircraft Corporation: Docket No. FAA-2010-0720; Directorate 
Identifier 2010-SW-050-AD.

    Applicability: Model S-92A helicopters, with main gearbox 
housing, part number 92351-15110-042, -043, -044, or -045, 
installed, certificated in any category.
    Compliance: Required as indicated, unless done previously.
    To prevent failure of the main gearbox housing mounting foot 
pad, loss of the main gearbox, and subsequent loss of control of the 
helicopter, do the following:
    (a) Within 60 days, revise the airworthiness limitations section 
of the Instructions for Continued Airworthiness by reducing the life 
limits of the affected main gearbox housing from 2700 hours time-in-
service (TIS) to 1000 hours TIS.
    (b) After revising the life limit in accordance with paragraph 
(a) of this AD, before further flight, replace any main gearbox 
housing that exceeds the life limit of 1000 hours TIS.
    (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: Michael Schwetz, Aviation Safety Engineer, 12 New England 
Executive Park, Burlington, MA 01803, telephone (781) 238-7761, fax 
(781) 238-7170, for information about previously approved 
alternative methods of compliance.
    (d) The Joint Aircraft System/Component (JASC) Code is 6320: 
Main Rotor Gearbox.

    Issued in Fort Worth, Texas, on July 13, 2010.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2010-17756 Filed 7-20-10; 8:45 am]
BILLING CODE 4910-13-P