[Federal Register Volume 62, Number 181 (Thursday, September 18, 1997)]
[Proposed Rules]
[Pages 48961-48963]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24795]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-SW-29-AD]
RIN 2120-AA64
Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
61A, D, E, L, N, NM, R, and V Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to Sikorsky Aircraft Corporation
(Sikorsky) Model S-61 A, D, E, L, N, NM, R, and V helicopters. This
proposal would require a nondestructive inspection (NDI) for cracks in
the main rotor shaft (shaft), and require removal of any shaft with a
crack and replacement with an airworthy shaft. This proposal would also
require appropriate marking of shafts and log book entries by the
operator to determine the shaft retirement life, and would establish a
new retirement life for the shaft. This proposal is prompted by four
reports of cracks occurring in helicopters that were utilized in
repetitive external lift (REL) operations. The actions specified by the
proposed AD are intended to detect a fatigue crack in the shaft, that
could result in shaft structural failure, loss of power to the main
rotor, and
[[Page 48962]]
subsequent loss of control of the helicopter.
DATES: Comments must be received by November 17, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 96-SW-29-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137. Comments may be inspected at this location between 9:00
a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be
obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial
Tech Support, 6900 Main Street, P.O. Box 9729, Stratford, CT 06497-
9129. This information may be examined at the FAA, Office of the
Assistant Chief Counsel, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas.
FOR FURTHER INFORMATION CONTACT: Mr. Frank Walsh, Aerospace Engineer,
ANE-150, 12 New England Executive Park, Burlington, MA 01803, telephone
(781) 238-7158, fax (781) 238-7199.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications should identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket No. 96-SW-29-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 96-SW-29-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
Discussion
This document proposes the adoption of a new AD that is applicable
to Sikorsky Model S-61 A, D, E, L, N, NM, R, and V helicopters. This
proposal would require a NDI of the shaft, part number (P/N) S6135-
20640-001, S6135-20640-002, or S6137-23040-001, used in REL operations
within the next 1,000 hours time-in-service (TIS), or at the next main
gearbox overhaul. The NDI would be required to be performed in
accordance with Sikorsky Alert Service Bulletin (ASB) No. 61B35-68,
dated July 19, 1996. This proposal would also establish retirement
lives for certain shafts utilized in REL operations. Therefore, for
shafts installed on helicopters utilized in REL operations that have
not been modified in accordance with Sikorsky Customer Service Notice
(CSN) 6135-10, dated March 18, 1987, and Sikorsky ASB No. 61B35-53,
dated December 2, 1981, the retirement life would be 1,500 hours time-
in-service (TIS). For shafts installed on helicopters utilized in REL
operations that have been modified in accordance with Sikorsky CSN
6135-10, dated March 18, 1987, and Sikorsky ASB No. 61B35-53, dated
December 2, 1981, the retirement life would be 2,000 hours TIS. This
proposal is prompted by four reports of cracks occurring in helicopters
that were utilized in REL operations. The actions specified by the
proposed AD are intended to detect a fatigue crack in the shaft, that
could result in shaft structural failure, loss of power to the main
rotor, and subsequent loss of control of the helicopter.
The FAA has reviewed Sikorsky ASB No. 61B35-68, dated July 19,
1996. That ASB describes procedures for determining the TIS during
which the helicopter was utilized in REL operations; performing a NDI
of the shaft; marking the shafts that have no crack; and acid-etching
the letters ``REL'' on airworthy shafts prior to their installation on
a helicopter that will be used in REL operations. The ASB also
establishes new life limits for the shaft.
Since an unsafe condition has been identified that is likely to
exist or develop on other Sikorsky Model S-61 A, D, E, L, N, NM, R, and
V helicopters of the same type design, the proposed AD would require
determining and recording on the component log or equivalent record the
number of hours TIS during which the helicopter was utilized in REL
operations, as well as the number of external lifts conducted during
each hour TIS in which external lifts were conducted; performing a NDI
of the shaft; marking the shafts that have no crack; and acid-etching
the letters ``REL'' on airworthy shafts prior to their installation on
a helicopter that will be used in REL operations. The proposed AD would
also establish a new retirement life for the shaft. The actions would
be required to be accomplished in accordance with the service bulletins
described previously.
The FAA estimates that 30 helicopters of U.S. registry that are
involved in REL operations would be affected by this proposed AD, that
it would take approximately 2.2 work hours per helicopter to accomplish
the proposed actions during the next scheduled overhaul, and that the
average labor rate is $60 per work hour. Required parts for the
inspection would cost approximately $50 per helicopter. Based on these
figures, the total cost impact of the proposed AD on U.S. operators is
estimated to be $5,460, assuming that no shafts will need to be
replaced as a result of this AD.
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that 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);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
[[Page 48963]]
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:
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. 96-SW-29-AD.
Applicability: Model S-61 A, D, E, L, N, NM, R, and V
helicopters, with main rotor shaft (shaft), part number (P/N) S6135-
20640-001, S6135-20640-002, or S6137-23040-001, installed,
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 detect a fatigue crack in the shaft, that could result in
shaft structural failure, loss of power to the main rotor, and
subsequent loss of control of the helicopter, accomplish the
following:
(a) Within the next 30 calendar days or 240 hours time-in-
service (TIS) after the effective date of this AD, whichever occurs
first, determine if the shaft has been used in repetitive external
lift (REL) operations. REL operation is defined as operation during
which the average number of external lifts equals or exceeds six per
flight hour for any 250 hour TIS period during the main gearbox
overhaul interval. An external lift is defined as a flight cycle in
which an external load is picked up, the helicopter is repositioned
(through flight or hover), and the helicopter hovers and releases
the load and departs or lands and departs. Record the total number
of hours TIS during which external lifts have been conducted, as
well as the number of external lifts conducted during each hour, on
the component log card or equivalent record. If the number of
external lifts cannot be determined, assume 6 external lifts were
conducted during each hour TIS in which external lifts were
conducted. If the hours TIS of external lift operations cannot be
determined, assume REL operations were conducted.
(b) For shafts used in REL operations, within the next 1,000
hours TIS after the effective date of this AD, conduct a non-
destructive inspection (NDI) for cracks in the shaft in accordance
with the Overhaul Manual. If a crack is discovered in a shaft,
remove the shaft and replace it with an airworthy shaft. Mark the
removed airworthy shafts and the replacement shafts in accordance
with the Accomplishment Instructions in paragraphs 2E and 2F of
Sikorsky Aircraft Corporation ASB No. 61B35-68, dated July 19, 1996.
Once a shaft has been designated and marked as an REL shaft, it is
life-limited accordingly for the remainder of that shaft's airworthy
service life.
(c) Retire all shafts that have been used in REL operations as
follows:
(1) Shafts that have been modified in accordance with Sikorsky
Customer Service Notice 6135-10, dated March 18, 1987, and Sikorsky
ASB No. 61B35-53, dated December 2, 1981 (modified REL shafts), must
be removed from service on or before attaining 2,000 hours TIS.
(2) Shafts that have not been modified in accordance with
Sikorsky Customer Service Notice 6135-10, dated March 18, 1987, and
Sikorsky ASB No. 61B35-53, dated December 2, 1981 (unmodified REL
shafts), must be removed from service on or before attaining 1,500
hours TIS.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Boston Aircraft Certification
Office. 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) This AD revises the Limitations section of the maintenance
manual by establishing new retirement lives of 1,500 hours TIS for
unmodified REL shafts and 2,000 hours TIS for modified REL shafts.
(f) 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.
Issued in Fort Worth, Texas, on September 12, 1997.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-24795 Filed 9-17-97; 8:45 am]
BILLING CODE 4910-13-U
