[Federal Register Volume 60, Number 92 (Friday, May 12, 1995)]
[Rules and Regulations]
[Pages 25611-25612]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11539]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-SW-18-AD; Amendment 39-9226; AD 95-10-09]
Airworthiness Directives; Sikorsky Aircraft Model S-58 and S-58T
Series Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Sikorsky Aircraft Model S-58 and S-58T series
helicopters, that requires the removal and replacement of the
transmission main gear box ring gear (ring gear) within certain time
intervals, and establishes a retirement life for the ring gear. This
amendment is prompted by reports of failures of the ring gear due to
slow-growth fatigue cracks. The actions specified by this AD are
intended to prevent failure of the ring gear, failure of the main
transmission, and subsequent loss of control of the helicopter.
DATES: Effective June 16, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 16, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Sikorsky Aircraft, Commercial Customer Support, 6900 Main
Street, Stratford, Connecticut 06601-1381. This information may be
examined at the FAA, Office of the Assistant Chief Counsel, 2601
Meacham Boulevard, Room 663, Fort Worth, Texas; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700, Washington,
DC.
FOR FURTHER INFORMATION CONTACT: Mr. Francis X. Walsh, Aerospace
Engineer, Boston Aircraft Certification Office, FAA, New England
Region, 12 New England Executive Park, Burlington, Massachusetts 01803-
5299, telephone (617) 238-7158, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to Sikorsky Aircraft Model S-58 and
S-58T series [[Page 25612]] helicopters was published in the Federal
Register on June 22, 1994 (59 FR 32144). That action proposed to
require the removal and replacement of the ring gear within certain
time intervals, and proposed to establish a retirement life for the
ring gear.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. No comments were received on the
proposal or the FAA's determination of the cost to the public. The FAA
has determined that air safety and the public interest require the
adoption of the rule as proposed. Since the issuance of the proposed
rule, the FAA has revised the average labor rate from $55 per work hour
to $60 per work hour, which increases the estimated cost impact on
operators to $486,250.
The FAA estimates that 125 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 31.5 work hours
per helicopter to accomplish the required actions, and that the average
labor rate is $60 per work hour. Required parts will cost approximately
$2,000 per helicopter. Based on these figures, the total cost impact of
the AD on U.S. operators is estimated to be $486,250.
The regulations adopted herein will not have substantial direct
effects 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. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (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); 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. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
95-10-09 Sikorsky Aircraft: Amendment 39-9226. Docket No. 93-SW-18-
AD.
Applicability: Model S-58 and S-58T series helicopters,
certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For helicopters that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (d) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition, or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any helicopter from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the transmission main gear box ring gear
(ring gear), failure of the main transmission, and subsequent loss
of control of the helicopter, accomplish the following:
(a) Within the next 25 hours time-in-service (TIS) after the
effective date of this AD, accomplish the following:
(1) From component records, determine the TIS for the ring gear,
part number (P/N) S1635-20058-2.
(i) If the TIS on the ring gear is 2,400 or more hours on the
effective date of this AD, replace it with an airworthy serialized
ring gear within the next 100 hours TIS.
(ii) If the TIS on the ring gear is less than 2,400 hours on the
effective date of this AD, replace it with an airworthy serialized
ring gear at or before reaching 2,500 hours TIS.
(2) If the TIS on the ring gear cannot be determined, replace it
in accordance with the time-since-last-overhaul (TSO) as follows:
(i) If the TSO on the ring gear is 1,150 or more hours on the
effective date of this AD, replace it with an airworthy serialized
ring gear within the next 100 hours TIS.
(ii) If the TSO on the ring gear is less than 1,150 hours on the
effective date of this AD, replace it with an airworthy serialized
ring gear at or before reaching 1,250 hours TSO.
(3) Create a component log and a serial number and apply the
serial number to the ring gear between the ring gear flanges in
accordance with Paragraph B of the Accomplishment Instructions of
Sikorsky Aircraft Alert Service Bulletin No. 58B35-32 (ASB 58B35-
32), dated July 6, 1993.
(b) Create a component log and a serial number for replacement
ring gears and apply the serial number to the ring gear between the
ring gear flanges in accordance with Paragraph B of the
Accomplishment Instructions of the ASB 58B35-32, dated July 6, 1993,
prior to installing a replacement ring gear on the helicopter.
(c) This AD establishes a retirement life of 2,500 hours TIS for
the ring gear. However, for ring gears with 2,400 or more hours TIS,
or if the TIS cannot be determined, 1,150 or more hours TSO on the
effective date of this AD, those ring gears need not be retired
until on or before the accumulation of an additional 100 hours TIS.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used when approved by the Manager, Boston Aircraft Certification
Office, FAA. Operators shall submit their requests through an FAA
Principal Maintenance Inspector, who may concur or comment and then
send it to the Manager, Boston Aircraft Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Boston Aircraft Certification Office.
(e) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the helicopter to a location where
the requirements of this AD can be accomplished.
(f) The removal and replacement shall be done in accordance with
Sikorsky Aircraft Alert Service Bulletin No. 58B35-32, dated July 6,
1993. This incorporation by reference was approved by the Director
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from Sikorsky Aircraft, Commercial
Customer Support, 6900 Main Street, Stratford, Connecticut 06601-
1381. Copies may be inspected at the FAA, Office of the Assistant
Chief Counsel, 2601 Meacham Boulevard, Room 663, Fort Worth, Texas;
or at the Office of the Federal Register, 800 North Capitol Street,
NW., suite 700, Washington, DC.
(g) This amendment becomes effective on June 16, 1995.
Issued in Fort Worth, Texas, on May 4, 1995.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 95-11539 Filed 5-11-95; 8:45 am]
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