Document ID: FAA-2008-0442-0011
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Various Sikorsky-Manufactured Transport and Restricted Category Helicopters
Posted Date: 2014-10-08T04:00Z

[Federal Register Volume 79, Number 195 (Wednesday, October 8, 2014)]
[Proposed Rules]
[Pages 60789-60793]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-23585]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0442; Directorate Identifier 2007-SW-24-AD]
RIN 2120-AA64

Airworthiness Directives; Various Sikorsky-Manufactured Transport 
and Restricted Category Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

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

-----------------------------------------------------------------------

SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain Sikorsky Aircraft Corporation (Sikorsky) Model S-61A, 
D, E, L, N, NM (serial number 61454), R, and V; Croman Corporation 
Model SH-3H, Carson Helicopters, Inc., Model S-61L; Glacier 
Helicopters, Inc. Model CH-3E; Robinson Air Crane, Inc. Model CH-3E, 
CH-3C, HH-3C, and HH-3E; and Siller Helicopters Model CH-3E and SH-3A 
helicopters. This SNPRM is prompted by comments received in response to 
a previous SNPRM and a reevaluation of the relevant data. This SNPRM 
retains the proposed actions in the previous SNPRM, provides an 
increased estimated cost of the main rotor shaft (MRS) replacement, and 
clarifies some of the language in the Required Actions section of the 
AD. The proposed actions are intended to prevent MRS structural 
failure, loss of power to the main rotor, and subsequent loss of 
control of the helicopter.

DATES: We must receive comments on this SNPRM by December 8, 2014.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the 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

[[Page 60790]]

Docket Management Facility between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays. The AD docket contains this proposed 
AD, the regulatory evaluation, any comments received, and other 
information. The street address for the Docket Office (phone: 800-647-
5527) is in the ADDRESSES section. Comments will be available in the AD 
docket shortly after receipt.
    For service information identified in this AD, contact Sikorsky 
Aircraft Corporation, Attn: Manager, Commercial Technical Support, 
mailstop s581a, 6900 Main Street, Stratford, CT, telephone (203) 383-
4866, email address tsslibrary@sikorsky.com, or at http://www.sikorsky.com. You may review a copy of the referenced service 
information at the FAA, Office of the Regional Counsel, 2601 Meacham 
Blvd., Room 663, Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Jeffrey Lee, Aviation Safety Engineer, 
Boston Aircraft Certification Office, 12 New England Executive Park, 
Burlington, MA 01803, telephone (781) 238-7161, fax (781) 238-7170, 
email jeffrey.lee@faa.gov.

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 April 10, 2008, we issued a notice of proposed rulemaking (NPRM) 
(73 FR 21556, April 22, 2008) proposing to amend 14 CFR part 39 to add 
an AD for Sikorsky Aircraft Corporation Model S-61A, D, E, L, N, NM, R, 
and V; Croman Corporation Model SH-3H, Carson Helicopters, Inc. Model 
S-61L; Glacier Helicopters, Inc. Model CH-3E; Robinson Air Crane, Inc. 
Model CH-3E, CH-3C, HH-3C and HH-3E; and Siller Helicopters Model CH-3E 
and SH-3A helicopters. The NPRM proposed superseding AD 98-26-02 (63 FR 
69177, December 16, 1998), which only applies to the affected Sikorsky 
model helicopters. The NPRM proposed retaining some of the requirements 
of AD 98-26-02 but also proposed determining a new retirement life for 
each MRS, removing from service any MRS with oversized dowel pin bores, 
and expanding the applicability to include the restricted category 
models that were inadvertently omitted from AD 98-26-02. The NPRM was 
prompted by the manufacturer's reevaluation of the retirement life for 
the MRS based on torque, ground-air-ground cycle, and fatigue testing. 
Those proposals were intended to prevent MRS structural failure, loss 
of power to the main rotor, and subsequent loss of control of the 
helicopter.
    On April 16, 2013, we issued an SNPRM (78 FR 24363, April 25, 2013) 
that proposed to revise the NPRM based on our review of the data and 
the comments received. The SNPRM proposed retaining the proposals in 
the NPRM and extending the hours time-in-service (TIS) required for 
identifying the MRS as a repetitive external lift (REL) MRS to coincide 
with the nondestructive inspection (NDI) to prevent repeated 
disassembly of the shaft. Also, the action proposed to extend the time 
required to replace the MRS and revise calculations for establishing 
the retirement life.

Actions Since Previous SNPRM Was Issued

    Since we issued the previous SNPRM (78 FR 24364, April 25, 2013), 
we have determined a need to revise the proposed requirements again 
based on our review of the data and the comments received. In addition 
to retaining the proposals in the previous SNPRM, this SNPRM changes 
the ``Costs of Compliance'' to reflect an increased cost to replace an 
MRS. Also, paragraph (f)(1)(ii) of the previous SNPRM provided that 
where there is no record of the hours TIS on an MRS, you may substitute 
the ``helicopter's hours TIS.'' To clarify some of the wording for 
complying with the AD, this SNPRM proposes that you may substitute the 
``helicopter's hours TIS or the helicopter's transmission hours TIS if 
both the shaft and transmission were installed new at the same time.''
    Because the proposed changes increase the economic burden on 
operators, we are reopening the comment period to allow the public to 
comment.

Comments

    We gave the public the opportunity to comment on the previous SNPRM 
(78 FR 24366, April 25, 2013). The following presents the comments 
received from two commenters and the FAA's response to those comments.

Request

    One commenter requested that we increase the life limits of 
modified REL shafts from 30,000 cycles to no less than 100,000 cycles 
because the proposed limit of 30,000 REL lift cycles is unreasonable 
and contrary to the manufacturer's current fatigue evaluation 
practices. The commenter stated the limit of 30,000 REL cycles ignores 
the crack-free service history for the modified MRS as well as several 
variables in operation. The commenter also stated the proposed 
requirements would impose an unacceptable punitive cost because the 
actual cost to replace an MRS is much higher than the cost identified 
in the SNPRM (78 FR 24366, April 25, 2013).
    We disagree. The commenter's proposed limit of 100,000 REL lift 
cycles is based on the working SN curve from fatigue testing that 
showed test specimen failure at 200,000 individual fatigue cycles. The 
data assumes that only the 103% torque event creates shaft damage and 
that one REL lift cycle is the same as one fatigue cycle. This 
assumption is not correct. One REL lift cycle includes many damaging 
fatigue cycles associated with a logging flight spectrum not accounted 
for by the commenter. The 30,000 REL lift cycle life limit is based 
upon the working SN curve from the fatigue tests and the fatigue damage 
determined by the logging flight loading spectrum. It is not only based 
on using the working SN curve cycle limit at the torque level chosen by 
the commenter. However, we agree with the commenter that the SNPRM does 
not reflect an accurate cost to replace an MRS. We have revised the 
``Costs of Compliance'' section to reflect the current cost of the MRS.
    The commenter also requested that the AD measure the shaft life 
limit by transmission TIS instead of the helicopter's TIS where no 
records exist for the main rotor shaft. The commenter states that the 
transmission TIS is a

[[Page 60791]]

better measure because most helicopters have more than 13,000 hours 
TIS.
    We partially agree. The requested change of language would only be 
accurate where both the shaft and transmission were installed new at 
the same time. This language would not be accurate where the 
transmission had been replaced earlier than the shaft and thus had a 
lower life than the shaft. Therefore, we have revised paragraph 
(f)(1)(ii) to include both ``helicopter's hours TIS'' and ``the 
helicopter's transmission hours TIS if both the shaft and transmission 
were installed new at the same time'' as options where no records exist 
for the main rotor shaft.
    The second commenter disagreed with determining pilot initial 
qualification by hours alone and suggested other methods. This comment 
appears to have been posted in error in this docket as it is not 
relevant to the SNPRM (78 FR 24366, April 25, 2013).

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 helicopters of these same type 
designs. Certain changes described above expand the scope of the 
previous SNPRM (78 FR 24363, April 25, 2013) by increasing the economic 
burden. As a result, we have determined that it is necessary to reopen 
the comment period to provide additional opportunity for the public to 
comment on this SNPRM.

Related Service Information

    Sikorsky has issued Customer Service Notice (CSN) No. 6135-10A and 
Sikorsky Service Bulletin (SB) No. 61B35-53A, both dated April 19, 
2004. The CSN and the SB apply to Model S-61L, N, and NM (serial number 
(S/N) 61454), and R series transport category helicopters; and S-61A, 
D, E, and V series restricted category helicopters. The CSN specifies 
replacing the planetary assembly and MRS assembly attaching hardware 
with high strength hardware. The CSN also specifies reworking the dowel 
retainer to increase hole chamfer and related countersink diameters. 
The SB specifies replacing the existing planetary matching plates with 
new steel matching plates during overhaul at the operator's discretion.
    Also, Sikorsky has issued ASB No. 61B35-69, dated April 19, 2004 
(ASB 61B35-69), which supersedes ASB 61B35-68B. ASB 61B35-69 provides 
updated procedures for determining REL and Non-REL status, assigns new 
REL and Non-REL MRS retirement lives, and provides a method for marking 
the REL MRS.

Proposed AD Requirements

    This proposed AD would retain some of the requirements from AD 98-
26-02 (63 FR 69177, December 16, 1998):
     Recording the number of external lift cycles (lift cycles) 
performed and the hours TIS.
     Determining whether the MRS is REL or Non-REL.
     Marking the REL MRS at the time of the NDI.
     Conducting an NDI for shafts used in REL operations and 
replacing it if there is a crack.
    The proposed AD would also require the following:
     When recording the number of hours TIS, using either the 
helicopter's hours TIS or the helicopter's transmission hours TIS if 
both the shaft and transmission were installed new at the same time 
where there is no record of the hours TIS on an individual MRS.
     Calculating a 250-hour TIS moving average of lift cycles 
to determine whether the MRS is an REL MRS.
     Determining a new retirement life for each MRS based on 
hours TIS and lift cycles.
     Removing from service any MRS with oversized dowel pin 
bores.
     Extending the retirement life of modified REL MRS from 
2,200 hours TIS to 5,000 hours TIS but also implementing lift-cycle 
retirement lives.
     Allowing the use of Revision A service information to 
modify the REL MRS for life limit determination.

Costs of Compliance

    We estimate that this proposed AD would affect 60 helicopters of 
U.S. registry. We estimate that operators may incur the following costs 
in order to comply with this proposed AD: It would take about 2.2 work 
hours to NDI an REL MRS at $85 per work hour plus a $50 consumable 
cost, for a total cost of $237 per helicopter and $14,220 for the U.S. 
fleet. It would take 2.2 work hours at $85 per work hour to replace an 
MRS, and parts would cost $81,216, for a total cost of $81,403 per 
helicopter.

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, 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. Amend Sec.  39.13 by removing Amendment 39-10943 (63 FR 69177, 
December 16, 1998), and adding the following new airworthiness 
directive (AD):

Sikorsky Aircraft Corporation; Croman Corporation; Carson 
Helicopters, Inc.;

[[Page 60792]]

Glacier Helicopters, Inc.; Robinson Air Crane, Inc.; and Siller 
Helicopters: Docket No. FAA-2008-0442; Directorate Identifier 2007-
SW-24-AD.

(a) Applicability

    This AD applies to Model S-61A, D, E, L, N, NM (serial number 
(S/N) 61454), R, V, CH-3C, CH-3E, HH-3C, HH-3E, SH-3A, and SH-3H 
helicopters with main rotor shaft (MRS), part number (P/N) S6135-
20640-001, S6135-20640-002, or S6137-23040-001, installed, 
certificated in any category.

(b) Unsafe Condition

    This AD defines the unsafe condition as MRS structural failure, 
loss of power to the main rotor, and subsequent loss of control of 
the helicopter.

(c) Affected ADs

    This AD supersedes AD 98-26-02 (63 FR 69177, December 16, 1998), 
Amendment 39-10943, Docket No. 96-SW-29-AD.

(d) Comments Due Date

    We must receive comments by December 8, 2014.

(e) 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.

(f) Required Actions

    (1) Within 10 hours time-in-service (TIS):
    (i) Create a component history card or equivalent record for 
each MRS.
    (ii) If there is no record of the hours TIS on an individual 
MRS, substitute the helicopter's hours TIS or the helicopter's 
transmission hours TIS if both the shaft and transmission were 
installed new at the same time.
    (iii) If the record of external lift cycles (lift cycles) on an 
individual MRS is incomplete, add the known number of lift cycles to 
a number calculated by multiplying the number of hours TIS of the 
individual MRS by the average lift cycles calculated according to 
the instructions in Section I of Appendix I of this AD or by a 
factor of 13.6, whichever is higher. An external lift cycle 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.
    (iv) At the end of each day's operations, record the number of 
lift cycles performed and the hours TIS.
    (2) Within 250 hours TIS, determine whether the MRS is a 
repetitive external lift (REL) or non-REL MRS.
    (i) Calculate the first moving average of lift cycles by 
following the instructions in Section I of Appendix I of this AD.
    (A) If the calculation results in 6 or more lift cycles per hour 
TIS, the MRS is an REL-MRS.
    (B) If the calculation results in less than 6 lift cycles per 
hour TIS, the MRS is a Non-REL MRS.
    (ii) If the MRS is a Non-REL MRS based on the calculation 
performed in accordance with paragraph (f)(2)(i), thereafter at 
intervals of 50 hour TIS, recalculate the average lift cycles per 
hour TIS by following the instructions in Section II of Appendix 1 
of this AD.
    (iii) Once an MRS is determined to be an REL MRS, you no longer 
need to perform the 250-hour TIS moving average calculation, but you 
must continue to count and record the lift cycles and number of 
hours TIS.
    (iv) If an MRS is determined to be an REL MRS, it remains an REL 
MRS for the rest of its service life and is subject to the 
retirement times for an REL MRS.
    (3) Within 1,100 hours TIS:
    (i) Conduct a Non-Destructive Inspection for a crack on each 
MRS. If there is a crack in an MRS, before further flight, replace 
it with an airworthy MRS.
    (ii) If an MRS is determined to be an REL MRS, identify it as an 
REL MRS by etching ``REL'' on the outside diameter of the MRS near 
the part S/N by following the Accomplishment Instructions, paragraph 
3.C., of Sikorsky Alert Service Bulletin (ASB) 61B35-69, dated April 
19, 2004.
    (4) Replace each MRS with an airworthy MRS on or before reaching 
the revised retirement life as follows:
    (i) For an REL MRS that is not modified by following Sikorsky 
Customer Service Notice (CSN) 6135-10, dated March 18, 1987, and ASB 
No. 61B35-53, dated December 2, 1981 (unmodified REL MRS), the 
retirement life is 30,000 lift cycles or 1,500 hours TIS, whichever 
occurs first.
    (ii) For an REL MRS that is modified by following Sikorsky CSN 
6135-10, dated March 18, 1987, and Sikorsky ASB No. 61B35-53 dated 
December 2, 1981, or CSN 6135-10A, Revision A, and ASB 61B35-53A, 
Revision A, both dated April 19, 2004 (modified REL MRS), the 
retirement life is 30,000 lift cycles or 5,000 hours TIS, whichever 
occurs first.
    (iii) For a non-REL MRS, the retirement life is 13,000 hours 
TIS.
    (5) Establish or revise the retirement lives of the MRS as 
indicated in paragraphs (f)(4)(i) through (f)(4)(iii) of this AD by 
recording the new or revised retirement life on the MRS component 
history card or equivalent record.
    (6) Within 50 hours TIS, remove from service any MRS with 
oversized (0.8860'' or greater diameter) dowel pin bores.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston Aircraft Certification Office, FAA, may 
approve AMOCs for this AD. Send your proposal to Jeffrey Lee, 
Aviation Safety Engineer, Boston Aircraft Certification Office, 12 
New England Executive Park, Burlington, MA 01803, telephone (781) 
238-7161, fax (781) 238-7170, email jeffrey.lee@faa.gov.
    (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

    (1) Sikorsky Aircraft Corporation issued an All Operators Letter 
(AOL) CCS-61-AOL-04-0005, dated May 18, 2004, with an example and 
additional information about tracking cycles and the moving average 
procedure. This AOL is not incorporated by reference but contains 
additional information about the subject of this AD.
    (2) The Overhaul and Repair Instruction (ORI) Number 6135-281, 
Part B, Step 5, and ORI 6137-041, Section III, Oversize Dowel Pin 
Bore Repair and identified on the flange as TS-281 or TS-041-3, 
which is not incorporated by reference, contains additional 
information about the subject of this AD.
    (3) For more information about the AOL or the ORI, contact 
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone 
(203) 383-4866, email address tsslibrary@sikorsky.com, or at http://www.sikorsky.com. You may review a copy of the referenced service 
information at the FAA, Office of the Regional Counsel, 2601 Meacham 
Blvd., Room 663, Fort Worth, Texas 76137.

Appendix I

Section I: The first moving average of lift cycles per hour TIS

    The first moving average calculation is performed on the MRS 
assembly when the external lift component history card record 
reflects that the MRS assembly has reached its first 250 hours TIS. 
To perform the calculation, divide the total number of lift cycles 
performed during the first 250 hours TIS by 250. The result will be 
the first moving average calculation of lift cycles per hour TIS.

Section II: Subsequent moving average of lift cycles per hour TIS

    Subsequent moving average calculations are performed on the MRS 
assembly at intervals of 50 hour TIS after the first moving average 
calculation. Subtract the total number of lift cycles performed 
during the first 50-hour TIS interval used in the previous moving 
average calculation from the total number of lift cycles performed 
on the MRS assembly during the previous 300 hours TIS. Divide this 
result by 250. The result will be the next or subsequent moving 
average calculation of lift cycles per hour TIS.

Section III: Sample calculation for subsequent 50 hour TIS intervals

    Assume the total number of lift cycles for the first 50 hour TIS 
interval used in the previous moving average calculation = 450 lift 
cycles and the total number of lift cycles for the previous 300 
hours TIS = 2700 lift cycles. The subsequent moving average of lift 
cycles per hour TIS = (2700 - 450) divided by 250 = 9 lift cycles 
per hour TIS.

 (i) Subject

    Joint Aircraft Service Component (JASC) Code: 6320, Main Rotor 
Gearbox.

[[Page 60793]]

    Issued in Fort Worth, Texas, on September 19, 2014.
Lance T. Gant,
Acting Directorate Manager, Rotorcraft Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-23585 Filed 10-7-14; 8:45 am]
BILLING CODE 4910-13-P