AD 2015-20-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | SH-3H | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | CH-3E | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | HH-3C | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | HH-3E | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61A | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61D | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61E | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61V | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61L | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61N | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61NM | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | S-61R | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
| aircraft | Carson Helicopters, Inc. | Croman Corporation | Glacier Helicopter, Inc. | Reynolds Aviation | Sikorsky Aircraft | Sikorsky Aircraft Corporation | Siller Helicopters | SH-3A | Airworthiness Directives; Various Sikorsky-Manufactured Transport and Restricted Category Helicopters |
Unsafe Condition
Main rotor shaft (MRS) structural failure, loss of power to the main rotor, and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Determine whether the MRS was used in repetitive external lift (REL) operations, perform a nondestructive inspection (NDI) for cracks, replace any unairworthy MRS, establish new retirement lives for each REL MRS, and remove from service any MRS with oversized dowel pin bores.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 12 months of the effective date (November 24, 2015).
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
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.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
We are superseding Airworthiness Directive (AD) 98-26-02 for certain Sikorsky Aircraft Corporation (Sikorsky) Model S-61A, D, E, L, N, NM, R, and V helicopters. AD 98-26-02 required determining whether the main rotor shaft (MRS) was used in repetitive external lift (REL) operations, performing a nondestructive inspection (NDI) for cracks, replacing any unairworthy MRS, and establishing retirement lives for each REL MRS. This new AD retains some of the requirements of AD 98-26- 02 but determines a new retirement life for each MRS, expands the applicability to include additional helicopters, and requires removing from service any MRS with oversized dowel pin bores. This AD was prompted by the manufacturer's reevaluation of the retirement life for the MRS based on torque, ground-air-ground (GAG) cycle, and fatigue testing. We are issuing this AD to prevent MRS structural failure, loss of power to the main rotor, and subsequent loss of control of the helicopter.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 80, Number 202 (Tuesday, October 20, 2015)]
[Rules and Regulations]
[Pages 63422-63425]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2015-25976]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0442; Directorate Identifier 2007-SW-24-AD;
Amendment 39-18291; AD 2015-20-12]
RIN 2120-AA64
Airworthiness Directives; Various Sikorsky-Manufactured Transport
and Restricted Category Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: We are superseding Airworthiness Directive (AD) 98-26-02 for
certain Sikorsky Aircraft Corporation (Sikorsky) Model S-61A, D, E, L,
N, NM, R, and V helicopters. AD 98-26-02 required determining whether
the main rotor shaft (MRS) was used in repetitive external lift (REL)
operations, performing a nondestructive inspection (NDI) for cracks,
replacing any unairworthy MRS, and establishing retirement lives for
each REL MRS. This new AD retains some of the requirements of AD 98-26-
02 but determines a new retirement life for each MRS, expands the
applicability to include additional helicopters, and requires removing
from service any MRS with oversized dowel pin bores. This AD was
prompted by the manufacturer's reevaluation of the retirement life for
the MRS based on torque, ground-air-ground (GAG) cycle, and fatigue
testing. We are issuing this AD to prevent MRS structural failure, loss
of power to the main rotor, and subsequent loss of control of the
helicopter.
DATES: This AD is effective November 24, 2015.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of November 24,
2015.
ADDRESSES: For service information identified in this AD, contact
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical
Support, mailstop s581a, 6900 Main Street, Stratford, Connecticut,
telephone (203) 383-4866, email <a href="/cdn-cgi/l/email-protection#b7c3c4c4dbded5c5d6c5cef7c4dedcd8c5c4dcce99d4d8da"><span class="__cf_email__" data-cfemail="106463637c7972627162695063797b7f62637b693e737f7d">[email protected]</span></a>, or at <a href="http://www.sikorsky.com">http://www.sikorsky.com</a>. You may view this referenced service information at
the FAA, Office of the Regional Counsel, 10101 Hillwood Pkwy, Room 6N-
321, Fort Worth, TX 76177.
Examining the AD Docket
You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a> in Docket No. FAA-2008-0442; or in person at the
Docket Management Facility between 9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays. The AD docket contains this AD, any
incorporated-by-reference information, the economic evaluation, any
comments received, and other information. The address for the Docket
Office (phone: 800-647-5527) is Document Management Facility, U.S.
Department of Transportation, Docket Operations, M-30, West Building
Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC
20590.
FOR FURTHER INFORMATION CONTACT: Tracy Murphy, Aviation Safety
Engineer, Boston Aircraft Certification Office, Engine & Propeller
Directorate, FAA, 12 New England Executive Park, Burlington,
Massachusetts 01803; telephone (781) 238-7172; email
<a href="/cdn-cgi/l/email-protection#05717764667c2b687077756d7c456364642b626a73"><span class="__cf_email__" data-cfemail="a5d1d7c4c6dc8bc8d0d7d5cddce5c3c4c48bc2cad3">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
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 by
adding 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
required determining whether the MRS was used in REL operations,
performing an NDI for cracks, replacing any unairworthy MRS, and
establishing retirement lives for each REL MRS. The NPRM proposed to
retain some of the requirements of AD 98-26-02 but also proposed a new
retirement life determination for each MRS, removing from service any
MRS with oversized dowel pin bores, and expanding the applicability to
include certain restricted category models. The NPRM was prompted by
the manufacturer's reevaluation of the retirement life for the MRS
based on torque, GAG cycle, and fatigue testing.
[[Page 63423]]
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 a supplemental NPRM (SNPRM) (78 FR
24363, April 25, 2013) that proposed to revise the NPRM based on
comments received on the NPRM and a reevaluation of the relevant data.
The SNPRM proposed retaining the proposals in the NPRM but extending
the hours TIS required for identifying the MRS as an REL MRS to
coincide with the NDI to prevent repeated disassembly of the shaft. The
SNPRM also proposed to extend the time required to replace the MRS and
revise calculations for establishing the retirement life.
On September 19, 2014, we issued a second SNPRM (79 FR 60789,
October 8, 2014). In addition to retaining previously-proposed
requirements, the second SNPRM revised the Cost of Compliance section
to reflect an increased cost for parts to replace an MRS and clarified
some of the wording for complying with the AD.
Since the SNPRM (79 FR 60789, October 8, 2014) was issued, the FAA
Southwest Regional Office has relocated. We have revised the physical
address to reflect the new address.
Comments
We gave the public the opportunity to participate in developing
this AD, but we did not receive any comments on the second SNPRM (79 FR
60789, October 8, 2014).
FAA's Determination
We have reviewed the relevant information and determined that an
unsafe condition exists and is likely to exist or develop on other
helicopters of these same type designs and that air safety and the
public interest require adopting the AD requirements as proposed except
for a minor change. Sikorsky Aircraft was inadvertently omitted as one
of the current type certificate holders of some of the applicable model
helicopters; we are correcting that error in this AD. This change is
consistent with the intent of the proposals in the SNPRM (79 FR 60789,
October 8, 2014) and will not increase the economic burden on any
operator nor increase the scope of the AD.
Related Service Information Under 1 CFR Part 51
Sikorsky issued Alert Service Bulletin No. 61B35-69, dated April
19, 2004, which provides 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. 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 of this AD.
Other Related Service Information
Sikorsky issued Customer Service Notice (CSN) No. 6135-10, dated
March 18, 1987, and Service Bulletin (SB) No. 61B35-53, dated December
2, 1981, both revised with Revision A on April 19, 2004, for 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. CSN 6135-10A specifies replacing the planetary assembly
and MRS assembly attaching hardware with high strength hardware. CSN
6135-10A also specifies reworking the dowel retainer to increase hole
chamfer and related countersink diameters. SB 61B35-53A specifies
replacing the existing planetary matching plates with new steel
matching plates during overhaul at the operator's discretion.
Sikorsky Aircraft Corporation also issued an All Operators Letter
CCS-61-AOL-04-0005, dated May 18, 2004, which contains an example and
additional information about tracking cycles and the moving average
procedure.
Costs of Compliance
We estimate that this AD affects 60 helicopters of U.S. Registry.
We estimate that operators may incur the following costs in order to
comply with this AD. It will take about 2.2 work-hours to NDI an REL
MRS at $85 per work-hour plus a $50 consumable cost, for a total
estimated cost of $237 per helicopter and $14,220 for the U.S. fleet.
It will take about 2.2 work-hours to replace an MRS at $85 per work-
hour plus parts cost of $81,216, for a total estimated 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 have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will 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 that this AD:
(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),
(3) Will not affect intrastate aviation in Alaska to the extent
that a regulatory distinction is required, 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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 removing Airworthiness Directive (AD)
98-26-02, Amendment 39-10943 (63 FR 69177, December 16, 1998), and
adding the following new AD:
2015-20-12 Sikorsky Aircraft Corporation; Sikorsky Aircraft; Croman
Corporation; Carson Helicopters, Inc.; Glacier Helicopters, Inc.;
Robinson Air Crane, Inc.; and Siller Helicopters: Amendment 39-
18291; Docket No. FAA-2008-0442; Directorate Identifier 2007-SW-24-
AD.
[[Page 63424]]
(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 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, Amendment 39-10943 (63 FR 69177,
December 16, 1998).
(d) Effective Date
This AD becomes effective November 24, 2015.
(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 1 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 1 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) of this AD,
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 No. 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) No. 6135-10, dated March 18, 1987, and
Sikorsky Service Bulletin (SB) 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
No. 6135-10, dated March 18, 1987, and Sikorsky SB No. 61B35-53
dated December 2, 1981; or Sikorsky CSN No. 6135-10A and Sikorsky SB
No. 61B35-53A, both Revision A, and 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: Tracy Murphy,
Aviation Safety Engineer, Boston Aircraft Certification Office,
Engine & Propeller Directorate, FAA, 12 New England Executive Park,
Burlington, Massachusetts 01803; telephone (781) 238-7172; email
<a href="/cdn-cgi/l/email-protection#97e3e5f6f4eeb9fae2e5e7ffeed7f1f6f6b9f0f8e1"><span class="__cf_email__" data-cfemail="b9cdcbd8dac097d4cccbc9d1c0f9dfd8d897ded6cf">[email protected]</span></a>.
(2) For operations conducted under a 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
Sikorsky Aircraft Corporation All Operators Letter CCS-61-AOL-
04-0005, dated May 18, 2004; Sikorsky Customer Service Notice (CSN)
No. 6135-10, dated March 18, 1987; Sikorsky CSN No. 6135-10A,
Revision A, dated April 19, 2004; Sikorsky Service Bulletin (SB) No.
61B35-53, dated December 2, 1981; and Sikorsky SB No. 61B35-53A,
Revision A, dated April 19, 2004, which are not incorporated by
reference, contain additional information about the subject of this
AD. For more information about these documents, contact Sikorsky
Aircraft Corporation, Attn: Manager, Commercial Technical Support,
mailstop s581a, 6900 Main Street, Stratford, Connecticut, telephone
(203) 383-4866, email <a href="/cdn-cgi/l/email-protection#6f1b1c1c03060d1d0e1d162f1c0604001d1c0416410c0002"><span class="__cf_email__" data-cfemail="98ecebebf4f1faeaf9eae1d8ebf1f3f7eaebf3e1b6fbf7f5">[email protected]</span></a>, or at <a href="http://www.sikorsky.com">http://www.sikorsky.com</a>. You may review a copy of the referenced service
information at the FAA, Office of the Regional Counsel, 10101
Hillwood Pkwy, Room 6N-321, Fort Worth, TX 76177.
(i) Subject
Joint Aircraft Service Component (JASC) Code: 6320, Main Rotor
Gearbox.
(j) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference of the service information listed in this
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
(i) Sikorsky Alert Service Bulletin No. 61B35-69, dated April
19, 2004.
(ii) Reserved.
(3) For Sikorsky service information identified in this AD,
contact Sikorsky Aircraft Corporation, Attn: Manager, Commercial
Technical Support, mailstop s581a, 6900 Main Street, Stratford,
Connecticut, telephone (203) 383-4866, email
<a href="/cdn-cgi/l/email-protection#2e5a5d5d42474c5c4f5c576e5d4745415c5d4557004d4143"><span class="__cf_email__" data-cfemail="225651514e4b405043505b62514b494d5051495b0c414d4f">[email protected]</span></a>, or at <a href="http://www.sikorsky.com">http://www.sikorsky.com</a>.
(4) You may view this service information at 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.
(5) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, call (202) 741-6030, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Appendix 1 to AD 2015-20-12
Section I: The First Moving Average of External Lift Cycles (Lift
Cycles) per Hour Time-in-Service (TIS)
The first moving average calculation is performed on the main
rotor shaft (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.
[[Page 63425]]
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.
Issued in Fort Worth, Texas, on October 4, 2015.
Lance T. Gant,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2015-25976 Filed 10-19-15; 8:45 am]
BILLING CODE 4910-13-P
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.