DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-26107; Project Identifier 2004-SW-30-AD]
RIN 2120-AA64

Airworthiness Directives; Carson Helicopters, Inc.; Croman
Corporation; Sikorsky Aircraft Corporation; and Siller Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.

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SUMMARY: The FAA is revising an earlier proposal for all Sikorsky
Aircraft Corporation Model S-61 A, D, E, and V helicopters; Croman
Corporation Model SH-3H helicopters, Carson Helicopters, Inc. Model S-
61L helicopters; and Siller Helicopters Model CH-3E and SH-3A
helicopters. This action revises the notice of proposed rulemaking
(NPRM) by adding camshaft and gear housing part numbers that need to be
marked and clarifying the applicability and certain compliance times.
The FAA is proposing this airworthiness directive (AD) to address the
unsafe condition on these products. Since these actions would impose an
additional burden over that in the NPRM, the FAA is reopening the
comment period to allow the public the chance to comment on these
changes.

DATES: The comment period for the NPRM published in the Federal
Register on October 30, 2006 (71 FR 63272), is reopened.

The FAA must receive comments on this SNPRM by April 29, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://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: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this SNPRM, contact your
local Sikorsky Field Representative or Sikorsky's Service Engineering
Group at Sikorsky Aircraft Corporation, 124 Quarry Road, Trumbull, CT
06611; telephone 1-800-Winged-S; email wcs_cust_service_eng.gr-sik@lmco
.com. Operators may also log on to the Sikorsky 360 website at
https://www.sikorsky360.com. You may view this service information at
the FAA, Office of the Regional Counsel, Southwest Region, 10101
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on
the availability of this material at the FAA, call 817-222-5110.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2006-26107;
or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this SNPRM, any comments received, and other information. The street
address for Docket Operations is listed above. Comments will be
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Isabel Saltzman, Aviation Safety
Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA
01803; telephone 781-238-7649; email Isabel.L.Saltzman@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2006-26107; Project
Identifier 2004-SW-30-AD" at the beginning of your comments. The most
helpful comments reference a specific portion of the proposal, explain
the reason for any recommended change, and include supporting data. The
FAA will consider all comments received by the closing date and may
amend this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposal.

Confidential Business Information

CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this SNPRM contain
commercial or financial information that is customarily treated as
private, that you actually treat as private, and that is relevant or
responsive to this NPRM, it is important that you clearly designate the
submitted comments as CBI. Please mark each page of your submission
containing CBI as "PROPIN." The FAA will treat such marked
submissions as confidential under the FOIA, and they will not be placed
in the public docket of this SNPRM. Submissions containing CBI should
be sent to Isabel Saltzman, Aviation Safety Engineer, Boston ACO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; telephone 781-
238-7649; email Isabel.L.Saltzman@faa.gov. Any commentary that the FAA
receives which is not specifically designated as CBI will be placed in
the public docket for this rulemaking.

Discussion

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to all Sikorsky Aircraft Corporation Model S-61 A, D, E,
and V helicopters; Croman Corporation Model SH-3H helicopters, Carson
Helicopters, Inc. Model S-61L helicopters; and Siller Helicopters Model
CH-3E and SH-3A helicopters. The NPRM published in the Federal Register
on October 30, 2006 (71 FR 63272). The NPRM proposed to require
creating a component history card or equivalent record and recording
the hours time-in-service (TIS) and the external lift cycles (lift
cycles) for each affected main gearbox input left and right freewheel
unit (IFWU) assembly. The NPRM also proposed to require determining if
the IFWU assembly is a repetitive external lift (REL) or non-REL IFWU
assembly. The determination includes calculating a moving average of
lift cycles per hour TIS at specified intervals on each IFWU assembly.
For REL IFWU assemblies, the NPRM proposed to require repetitive
inspections, which include visual and dimensional inspections, of the
IFWU assembly for wear, surface distress, and endplay, recording
certain information, and replacing affected parts with an airworthy
part. In addition, the NPRM proposed to require permanently marking the
REL IFWU camshafts and gear housings with the letters "REL" on the
surface of these parts.

The NPRM was prompted by an accident in which the left and right
IFWU assembly on a helicopter slipped or disengaged, resulting in both
engines overspeeding, engine shutdowns, and loss of engine power to the
transmissions. The FAA is proposing this AD to address slipping of the
main gearbox IFWU assembly, loss of engine power, and subsequent loss
of control of the helicopter.

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, the FAA determined that additional
camshaft and gear housing part numbers need to be marked and the
applicability and certain compliance times need clarification.

Comments

The FAA gave the public the opportunity to participate in
developing this proposed AD. The FAA has considered the comments
received.

Request To Fix Typographical Errors

Sikorsky Aircraft Corporation (Sikorsky) requested that the FAA fix
two typographical errors. Sikorsky stated that in the third paragraph
of the Discussion section in the NPRM, the citation for the alert
service bulletin should read ". . . 61B35-67B . . ." (not "61835-
67B"), and the citation for the all operators letter should read ". .
. CCS-61-AOL-04-0005" (not "CCS-61AOL-04-0005").

The FAA agrees with the request. The FAA has revised the citations
accordingly.

Request To Revise Etching Language

Sikorsky requested that the etching language in paragraph (d) of
the proposed AD (in the NPRM) (referred to as paragraph (j) of this
proposed AD (in the SNPRM)) be revised from "After etching neutralize
the etched surface with oil to prevent corrosion" to the following:
"After etching, neutralize the etched surface and oil to prevent
corrosion."

The FAA agrees with the request. The FAA has also clarified the
compliance time by specifying "Before further flight and after
etching, neutralize the etched surface and oil to prevent corrosion"
in paragraph (j) of this proposed AD.

Request To Add Camshaft and Gear Housing Part Numbers

Sikorsky requested that the FAA add camshaft and gear housing part
numbers to the "Compliance" section of the proposed AD. Sikorsky
stated that additional IFWU camshaft part numbers 61350-24052 and
61350-24072 have been delivered in military versions of the S-61 and
should be included on the assumption that some of these aircraft have
been or may become certificated. Sikorsky also stated that additional
IFWU gear housing part numbers 61350-24051 and 61350-24068 have been
delivered in military versions of the S-61 and should be included on
the assumption that some of these aircraft have been or may become
certificated.

The FAA agrees. Paragraph (j) of this proposed AD has been revised
accordingly.

Request To Require Installation of Redesigned IFWUs

Croman Corporation stated a redesigned #2 IFWU could be installed
in the commercial gear box with minimal modifications, mostly to the
oil system. The FAA infers that the commenter is requesting that the
proposed AD require installing redesigned #2 IFWUs in lieu of
accomplishing the proposed actions (i.e., creating a component history
card or equivalent record and recording the hours TIS and the lift
cycles for each affected main gearbox IFWU assembly; determining if the
IFWU assembly is a REL or non-REL assembly; for REL IFWU assemblies,
repetitive inspections of the IFWU assembly for wear, surface distress,
and endplay, recording certain information, and replacing affected
parts; and permanently marking the REL IFWU camshafts and gear
housings).

The FAA does not concur. The FAA has determined that the proposed
actions adequately address the identified unsafe condition. However,
the FAA might consider additional rulemaking if sufficient data is
submitted to substantiate requiring the replacement of the IFWUs in
lieu of doing the proposed actions.

Clarification of the Model Designations

The applicability of the proposed AD (in the NPRM) refers to Model
S-61 A, D, E, V, SH-3H, S-61L; CH-3E, and SH-3A helicopters. The FAA
has revised the applicability of this proposed AD (in the SNPRM) to
refer to the model designations as specified in the most recent U.S.
type certificate data sheet: Carson Helicopters, Inc., Model S-61L
helicopters; Carson Helicopters, Inc., Model SH-3H helicopters; Croman
Corporation Model SH-3H helicopters; Sikorsky Aircraft Corporation
Model S-61A, S-61D, S-61E, and S-61V helicopters; Siller Helicopters
Model CH-3E helicopters; and Siller Helicopters Model SH-3A
helicopters.

Clarification of Certain Compliance Times

The FAA has clarified the compliance times specified in paragraphs
(g), (h)(1), (i)(1), and (j) of this proposed AD.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Sikorsky Aircraft Corporation Alert Service
Bulletin 61B35-67B, Revision B, dated August 11, 2003. This service
information describes, among other actions, procedures for inspections,
which includes visual and dimensional inspections, of the IFWU assembly
for wear, surface distress, and endplay, and for recording certain
information. This service information is reasonably available because
the interested parties have access to it through their normal course of
business or by the means identified in the ADDRESSES section.

Other Related Service Information

The FAA also reviewed Sikorsky Aircraft Corporation All Operators
Letter (AOL) CCS-61-AOL-04-0005, dated May 18, 2004. This service
information provides an example and additional information about
tracking cycles and the moving average procedure.

The FAA also reviewed Sikorsky Aircraft S-61L/N Overhaul Manual,
SA4045-83, Revision 20, dated August 15, 2003, as revised by Temporary
Revisions 65-193, -194, -195, and -196, which contains the overhaul
procedures for the IFWU assembly.

FAA's Determination

The FAA is proposing this AD because the agency evaluated all the
relevant information and determined the unsafe condition described
previously is likely to exist or develop in other products of the same
type design. Certain changes described above expand the scope of the
NPRM. As a result, the FAA has determined that it is necessary to
reopen the comment period to provide additional opportunity for the
public to comment on this SNPRM.

Proposed Requirements of This SNPRM

This SNPRM would require creating a component history card or
equivalent record and recording the hours TIS and the lift cycles for
each affected main gearbox IFWU assembly; determining if the IFWU
assembly is a REL or non-REL assembly; for REL IFWU assemblies,
repetitive inspections of the IFWU assembly for wear, surface distress,
and endplay, recording certain information, and replacing affected
parts; and permanently marking the REL IFWU camshafts and gear
housings.

Differences Between This Proposed AD and the Service Information

The effectivity of Sikorsky Aircraft Corporation Alert Service
Bulletin 61B35-67B, Revision B, dated August 11, 2003, includes Model
S-61 L, N, NM, and R helicopters. However, for those helicopters, the
unsafe condition is addressed in AD 2007-01-05, Amendment 39-14876 (72
FR 1139, January 10, 2007). Therefore, those helicopters are not
included in the applicability of this proposed AD.

Sikorsky Aircraft Corporation Alert Service Bulletin 61B35-67B,
Revision B, dated August 11, 2003, specifies contacting Sikorsky and
providing information to Sikorsky. This proposed AD does not require
you to contact Sikorsky or provide information to Sikorsky.

Costs of Compliance

The FAA estimates that this proposed AD affects 55 helicopters of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:

Estimated Costs

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.

The FAA is 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

The FAA 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) Will not affect intrastate aviation in Alaska, 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.

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

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. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):