[Federal Register Volume 79, Number 3 (Monday, January 6, 2014)]
[Rules and Regulations]
[Pages 549-551]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-31525]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0945; Directorate Identifier 2010-SW-110-AD; 
Amendment 39-17722; AD 2013-26-13]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
(Sikorsky) Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for 
Sikorsky Model S-70, S-70A, S-70C, S-70C (M), and S-70C (M1) 
helicopters with General Electric (GE) T700-GE-401C or T700-GE-701C 
engines installed. This AD requires establishing new fatigue life 
limits for certain GE engine gas generator turbine (GGT) rotor parts. 
This AD was prompted by a reevaluation of the method for determining 
the life limit for certain GE engine GGT rotor parts and the 
determination that these life limits should be based on low cycle 
fatigue (LCF) events instead of hours time-in-service (TIS). The 
actions are intended to prevent fatigue failure of a GGT rotor part, 
engine failure, and subsequent loss of control of the helicopter.

DATES: This AD is effective February 10, 2014.
    The Director of the Federal Register approved the incorporation by 
reference of certain documents listed in this AD as of February 10, 
2014.

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

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 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: Michael Davison, Flight Test Engineer, 
New England Regional Office, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: (781) 238-7156; fax: (781) 238-7170; 
email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    On September 7, 2012, at 77 FR 55166, 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-70, S-70A, S-70C, S-70C (M), and S-70C (M1) helicopters with GE T700-
GE-401C or T700-GE-701C engines installed. The NPRM proposed 
establishing new fatigue life limits for certain GE engine GGT rotor 
parts, based upon a formula in GE's service information. The NPRM was 
prompted by the determination that the affected engines could fail due 
to fatigue unless the life limits of certain GE engine rotor parts are 
changed from hours TIS to LCF events.
    On July 23, 2013, at 78 FR 44052, the Federal Register published 
our supplemental notice of proposed rulemaking (SNPRM), which proposed 
to revise the formula in the NPRM for establishing the new fatigue life 
limits by using the correct formula in a newer revision of GE's service 
information. Also, the SNPRM corrected a typographical error made in 
the preamble of the previous NPRM in the ``Related Service 
Information,'' which referenced the service bulletin number as 72-041 
rather than the correct service bulletin number 72-0041.
    The proposed actions in the SNPRM were intended to prevent failure 
of a GGT rotor part, engine failure, and subsequent loss of control of 
the helicopter.

Comments

    We gave the public the opportunity to comment on the NPRM (77 FR 
55166, September 7, 2012), and the SNPRM (78 FR 44052, July 23, 2013), 
but we did not receive any comments.

FAA's Determination

    We have reviewed the relevant information 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 in the SNPRM 
(78 FR 44052, July 23, 2013).

Costs of Compliance

    We estimate that this AD will affect 9 helicopters of U.S. 
registry. We estimate that operators may incur the following costs in 
order to comply with this AD: A minimal amount for work hours and labor 
costs because these parts are replaced as part of the periodic 
maintenance on the helicopter; a minimal amount of time to calculate 
the new retirement life; $360,000 to replace the GGT rotor parts per 
helicopter; and $3,240,000 to replace the GGT rotor parts for the 
entire U.S. operator fleet.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I,

[[Page 550]]

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):

2013-26-13 Sikorsky Aircraft Corporation: Amendment 39-17722; Docket 
No. FAA-2012-0945; Directorate Identifier 2010-SW-110-AD.

 (a) Applicability

    This AD applies to Model S-70, S-70A, S-70C, S-70C (M), and S-
70C (M1) helicopters with General Electric (GE) T700-GE-401C or 
T700-GE-701C part-numbered engines, certificated in any category.

 (b) Unsafe Condition

    This AD defines the unsafe condition as a critical engine part 
remaining in service beyond its fatigue life because the current 
life limit is based on hours time-in-service (TIS) instead of 
fatigue cycles. This condition could result in fatigue failure of an 
engine rotor part, engine failure, and subsequent loss of control of 
the helicopter.

(c) Effective Date

    This AD becomes effective February 10, 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 Actions

    (1) Before further flight, insert into the airworthiness 
limitations section of the maintenance manual or instructions for 
continued airworthiness the low cycle fatigue (LCF) limit diagrams 
shown in Figures 2 through 7 (pages 9 through 14) of GE T700 
Turboshaft Engine Service Bulletin T700 S/B 72-0041, Revision 1, 
dated March 12, 2010, for helicopters with the GE T700-GE-401C 
engine, or Figures 2 through 4 (pages 10 through 12) of GE T700 
Turboshaft Engine Service Bulletin T700 S/B 72-0038, dated October 
1, 2008, for helicopters with the GE T700-GE-701C engine. The 
diagonal line on each diagram represents the new cycle life limit (a 
combination of full low cycle fatigue events (LCF1) and partial low 
cycle fatigue events (LCF2) as those terms are defined in the 
Accomplishment Instructions, paragraphs 3.A.(1) and 3.A.(2) of each 
service bulletin) for each gas generator turbine (GGT) rotor part. A 
combination of LCF1 and LCF2, which results in a number below the 
diagonal line of the applicable diagram for each engine, indicates 
that the part has not reached its fatigue life limit.
    (2) Before further flight:
    (i) Obtain the actual LCF1 and LCF2 count from the engine 
``history recorder'' (HR);
    (ii) Calculate the LCF1 and LCF2 fatigue retirement life for 
each GGT rotor part as follows:
    (A) Determine the actual LCF ratio by dividing the total actual 
LCF2 cycle count obtained from the HR by the total actual LCF1 cycle 
count obtained from the HR. Add to the actual counts from the HR any 
actual additional fatigue cycle incurred during any period in which 
the HR was inoperative.
    (B) Determine the LCF1 retirement life by dividing the maximum 
number of LCF2 events obtained from the applicable diagram for each 
engine by the sum of the actual LCF ratio obtained by following 
paragraph (e)(2)(ii)(A) of this AD plus the quotient of the maximum 
number of LCF2 events from the applicable diagram for each engine 
divided by the maximum number of LCF1 events from the applicable 
diagram for each engine.
    (C) Determine the LCF2 retirement life by multiplying the actual 
LCF ratio obtained by following paragraph (e)(2)(ii)(A) of this AD 
times the LCF1 retirement life determined by following paragraph 
(e)(2)(ii)(B) of this AD.
    (iii) Replace each GGT rotor part that has reached the new 
fatigue cycle life limit with an airworthy rotor part.
    (3) For helicopters with the GE T700-GE-401C engine, if you 
cannot determine the number of low cycle fatigue events manually 
from the HR or by combining both manual and HR counts, then the life 
limit for the GGT rotor part is the hours TIS for the part as shown 
in Table 1 of GE T700 Turboshaft Engine Service Bulletin T700 S/B 
72-0041, dated August 21, 2009.
    (4) Before further flight, begin or continue to count the full 
and partial low fatigue cycle events and record on the component 
card or equivalent record that count at the end of each day for 
which the HR is inoperative.

 (f) Special Flight Permit

    Special flight permits will not be issued to allow flight in 
excess of life limits.

 (g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to: Michael Davison, 
Flight Test Engineer, New England Regional Office, FAA, 12 New 
England Executive Park, Burlington, MA 01803; phone: (781) 238-7156; 
fax: (781) 238-7170; email: [email protected].
    (2) For operations conducted under 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) Subject

    Joint Aircraft Service Component (JASC) Code: 7250: Turbine 
Section.

 (i) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) 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) General Electric (GE) T700 Turboshaft Engine Service 
Bulletin T700 S/B 72-0038, dated October 1, 2008.
    (ii) GE T700 Turboshaft Engine Service Bulletin T700 S/B 72-
0041, dated August 21, 2009.

[[Page 551]]

    (iii) GE T700 Turboshaft Engine Service Bulletin T700 S/B 72-
0041, Revision 1, dated March 12, 2010.
    (3) For GE service information identified in this AD, contact 
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone 
(800) 562-4409, email address [email protected], or at http://www.sikorsky.com.
    (4) You may view this service information at 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.
    (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 24, 2013.
Kim Smith,
Directorate Manager, Rotorcraft Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-31525 Filed 1-3-14; 8:45 am]
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