[Federal Register Volume 78, Number 141 (Tuesday, July 23, 2013)]
[Proposed Rules]
[Pages 44052-44054]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-17627]
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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]
RIN 2120-AA64
Airworthiness Directives; Sikorsky Aircraft Corporation
(Sikorsky) Model Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of the comment period.
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SUMMARY: We are revising an earlier proposed airworthiness directive
(AD) for the 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, which proposed establishing new fatigue life
limits for certain GE engine gas generator turbine (GGT) rotor parts.
The proposed AD was prompted by a reevaluation of the method for
determining the life limit for certain GE engine gas generator turbine
(GGT) rotor parts and the determination that these life limits need to
be based on low cycle fatigue (LCF) events instead of hours time-in-
service. This action would retain the previously proposed requirements
but correct the life limit formula for a certain GGT rotor part. The
proposed actions are intended to prevent fatigue failure of a GGT rotor
part, engine failure, 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 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:
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 August 30, 2012, we issued a notice of proposed rulemaking
(NPRM) (77 FR 55166, September 7, 2012) for 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 to require
establishing a new life limit for certain GGT rotor parts based upon
the accumulated LCF events of the GGT rotor parts. 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 time-in-service to LCF events. The GE T700-GE-701C
engine is used in the military's UH-60 fleet. Analysis and experience
with this engine have caused the military to reduce the life limit of
certain GGT rotor parts and to revise their maintenance documentation
to reflect these revised life limits. The Sikorsky Model S-70
helicopters are similar to the military's UH-60 fleet, some of which
have been certificated by the FAA in the restricted category. The GE
T700-GE-701C engine has not been type-certificated by the FAA for civil
use, except to the extent that it is a part of a restricted category
Model S-70 helicopter.
[[Page 44053]]
Actions Since Previous NPRM Was Issued
Since we issued the previous NPRM (77 FR 55166, September 7, 2012),
we became aware that GE has issued T700 Turboshaft Engine Service
Bulletin (ESB) 72-0041, Revision 1, dated March 12, 2010 (ESB 72-0041),
to correct the formula under the ``T700-GE-401C Stage 2 Disk PN
6064T12P01/P03 LCF Limit Diagram'' in Figure 6. Other than this
correction, the specifications in ESB 72-0041 remain the same.
This SNPRM proposes to retain the previously proposed requirements
but apply the correct life limit formula depicted in Figure 6 of ESB
72-0041, Revision 1. Also, we are correcting a typographical error in
the preamble of the previous NPRM in the ``Related Service
Information,'' which referenced the ESB number as 72-041 rather than
72-0041. As a result, we have determined that it is necessary to reopen
the comment period to provide additional opportunity for the public to
comment.
Comments
We gave the public the opportunity to comment on the original NPRM
(77 FR 55166, September 7, 2012), but we did not receive any comments.
FAA's Determination
We are proposing this SNPRM because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of these same type
designs.
Proposed Requirements of the SNPRM
This SNPRM would retain the proposed requirements of the previous
NPRM and would also propose inserting into the airworthiness
limitations section of the maintenance manual or the instructions for
continued airworthiness the figures contained in ESB No. T700 S/B 72-
0041, Revision 1, dated March 12, 2010, instead of ESB No. T700 S/B 72-
0041, dated October 1, 2008.
Costs of Compliance
We estimate that this proposed AD would 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, 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
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 above, 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: 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) Comments Due Date
We must receive comments by September 23, 2013.
(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 (ESB) No. 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 ESB No. 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 ESB) 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:
[[Page 44054]]
(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 ESB No. 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) 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, 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.
(i) Subject
Joint Aircraft Service Component (JASC) Code: 7250: Turbine
Section.
Issued in Fort Worth, Texas, on July 11, 2013.
Kim Smith,
Directorate Manager, Rotorcraft Directorate, Aircraft Certification
Service.
[FR Doc. 2013-17627 Filed 7-22-13; 8:45 am]
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