[Federal Register Volume 66, Number 198 (Friday, October 12, 2001)]
[Proposed Rules]
[Pages 52073-52076]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-25696]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-SW-46-AD]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76A Helicopter

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes superseding an existing airworthiness 
directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A 
helicopters. That AD currently requires a service life limit on certain 
landing gear parts based on hours time-in-service (TIS). This action 
would add another method of calculating the life limit for certain 
landing gear parts based on cycles and would require the operator to 
choose and record the method of calculating the service life of each 
part in the rotorcraft history or equivalent record. This action would 
also require replacing the part based upon either the maximum hours TIS 
or the maximum cycles but not both. This proposal is prompted by the 
need to add flight cycles as a method of calculating the life limit for 
certain landing gear parts based on fatigue analyses. The actions 
required by the proposed AD are intended to add or revise the 
retirement life for certain landing gear parts to prevent fatigue 
failure of the landing gear and subsequent loss of control of the 
helicopter.

DATES: Comments must be received on or before December 11, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2000-SW-46-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: [email protected]. 
Comments may be inspected at the Office of the Regional Counsel between 
9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Richard Noll, Aviation Safety 
Engineer, Boston Aircraft Certification Office, 12 New England 
Executive Park, Burlington, MA 01803, telephone (781) 238-7160, 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 will 
be considered before taking action on the proposed rule. The proposals 
contained in this document 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 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 mailed 
comments submitted in response to this proposal must submit a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. 2000-SW-

[[Page 52074]]

46-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 Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2000-SW-46-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137.

Discussion

    On April 23, 1986, the FAA issued AD 86-09-11, Amendment 39-5298 
(51 FR 17009, May 8, 1986), to require placing a service life limit on 
certain landing gear parts on Sikorsky Model S-76A helicopters based on 
hours TIS. That action was prompted by safety considerations and 
landing gear fatigue analysis. The requirements of that AD are intended 
to prevent fatigue failure of landing gear parts and landing gear.
    Since the issuance of that AD, Sikorsky has issued a revision and a 
Supplement No.1 to the Airworthiness Limitations Section, Chapter 4, of 
the Sikorsky Maintenance Manual SA 4047-76-2-1. Replacing the parts in 
accordance with the revisions dated May 9, 1997 (page 1), and March 2, 
1999 (page 2), constitutes compliance with this AD when applied to 
helicopters that have not been modified by Supplemental Type 
Certificate (STC) SH568NE. Replacing the parts in accordance with 
Supplement No. 1, dated May 21, 1997, revised pages 2 and 3 dated March 
2, 1999, constitutes compliance with this AD when applied to 
helicopters that have been modified by STC SH568NE. The change and 
supplement specify replacing parts installed in the Sikorsky Model S-
76A helicopter at the expiration of a specified number of cycles.
    The life limit in AD 86-09-11 is based on hours TIS, and the life 
limit in the airworthiness limitations section of the maintenance 
manual is based on cycles. The proposed AD would supersede AD 86-09-11, 
retaining a life limit based on hours TIS but also allowing the life 
limit to be based on cycles for certain landing gear parts. The 
proposed AD would also require recording the method selected for 
calculating the life limit of the landing gear parts in the rotorcraft 
history or equivalent records and using only that method throughout the 
life of the part. A cycle is defined as one takeoff to a hover or other 
mode of flight and one landing.
    The FAA estimates that 87 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 2 work 
hours per helicopter to determine the number of cycles, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be $10,440.
    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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.

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 removing Amendment 39-5298 (51 FR 
17009, May 8, 1986), and by adding a new airworthiness directive (AD), 
to read as follows:

Sikorsky Aircraft Corporation: Docket No. 2000-SW-46-AD. Supersedes 
AD 86-09-11, Amendment 39-5298, Docket No. 86-ASW-12.

    Applicability: Model S-76A 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 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fatigue failures of the main and nose landing gear 
parts and subsequent loss of control of the helicopter, accomplish 
the following:
    (a) Within 50 hours time-in-service (TIS), determine either the 
hours TIS or cycles accumulated on each part listed in Table 1 or 
Table 2 of this AD, as applicable. A cycle is a takeoff to a hover 
or other mode of flight and a landing.
    (1) If neither the hours TIS nor cycles are known for an 
affected part, assume the rotorcraft's total hours TIS are the hours 
TIS for that part.
    (2) If only one history is known for the part (either hours TIS 
or cycles), use that method for tracking the remaining life of that 
part.
    (3) Thereafter, record in the rotorcraft history or equivalent 
record the selected method of calculating the life limit for each 
landing gear part, and record either the accumulated hours TIS or 
cycles for the selected method.
    (b) Before further flight, remove from service each part listed 
in the following Table 1 of this AD on or before reaching the 
applicable life limit:

                                                     Table 1
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                                                                                    Life limit      Life limit
               Component                                Part No.                     hours TIS        cycles
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(1) Main Landing Gear:
    (i) Cylinder......................  1945E2                                            30,300         136,350
    (ii) Axle Support Fitting.........  1945C12                                            9,600          43,200

[[Page 52075]]

 
    (iii) Pin, Universal to Cylinder..  1945C29                                           23,800         107,100
    (iv) Drag Brace Rod End...........  1945E35                                           38,200         171,900
    (v) Upper Torque Arm..............  1945E46                                           37,900         170,550
    (vi) Lower Torque Arm.............  1945C47                                           16,200          72,900
    (vii) Axle........................  195E85                                            23,380         105,210
    (viii) Rod End, Positioning Rod...  1945E235                                          19,100          85,950
    (ix) Retraction Actuator:
        (A) Outer Cylinder............  1945E302, 1945F302                                 7,100          31,950
        (B) Piston....................  1945E314                                          33,300         148,500
        (C) Piston Rod End............  01-747-061                                         8,000          36,000
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(2) Nose Landing Gear:
    (i) Fork..........................  1944E60                                           42,500         191,250
    (ii) Cylinder.....................  1944C2, 1944E2                                    18,500          83,250
    (iii) Drag Brace Actuator:
        (A) Cylinder Terminal.........  1944D201                                          28,800         129,600
        (B) Piston Rod................  1944E204                                          22,000          99,000
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    (c) For helicopters modified by Supplemental Type Certificate 
(STC) SH568NE, before further flight, remove from service each part 
listed in the following Table 2 of this AD on or before reaching the 
applicable life limit:

                                                     Table 2
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                                                                                    Life limit      Life limit
               Component                                Part No.                     hours TIS        cycles
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(1) Main Landing Gear:
    (i) Cylinder......................  1945E2, 2071-2                                    24,000         108,000
    (ii) Piston.......................  1945E4, 2071-4                                    28,600         128,700
    (iii) Axle Support Fitting........  1945C12, 2071-12                                   7,400          33,300
    (iv) Pin, Universal to Cylinder...  1945C29, 2071-29                                  16,000          72,000
    (v) Pin, Positioning Rod to Upper   1945A32, 2071-32                                  25,000         112,500
     Torque Arm.
    (vi) Drag Brace Rod End...........  1945E35, 2071-35                                  23,864         107,388
    (vii) Upper Torque Arm............  1945E46, 2071-46                                  26,829         120,730
    (viii) Lower Torque Arm...........  1945C47, 2071-47                                  11,928          53,676
    (ix) Lower Drag Brace.............  1945E74, 2071-74                                  46,000         207,000
    (x) Retraction Brace..............  1945E76A11, 1945E76A12, 2071-76-11, 2071-         41,000         184,500
                                         76-12
    (xi) Axle.........................  1945E85, 2071-85                                  23,380         105,210
    (xii) Rod End, Positioning Rod....  1945E235, 2071-235                                13,600          61,200
    (xiii) Retraction Actuator:
        (A) Outer Cylinder............  1945E302, 1945F302                                 7,100          31,950
        (B) Piston....................  1945E314                                          33,000         148,500
        (C) Piston Rod End............  01-747-061                                         8,000          36,000
----------------------------------------------------------------------------------------------------------------
(2) Nose Landing Gear:
    (i) Axle..........................  1944B85, 2070-85                                  49,833         224,248
    (ii) Fork.........................  1944E60, 2070-60                                  32,000         144,000
    (iii) Piston......................  1944E4, 2070-4                                    35,878         161,451
    (iv) Cylinder.....................  1944C2, 1944E2, 2070-2                            13,500          60,750
    (v) Drag Brace Actuator:
        (A) Cylinder Terminal.........  1944D201, 2070-201                                23,000         103,500
        (B) Piston Terminal...........  1944E212B, 2070-212                               40,000         180,000
        (C) Piston Rod................  1944E204                                          22,000          99,000
----------------------------------------------------------------------------------------------------------------

    (d) This AD revises the Limitations section of the maintenance 
manual by establishing or revising the retirement lives for the 
affected parts shown in Tables 1 and 2 of this AD and establishing 
cycle counting as an additional method to determine retirement for 
the affected parts. Installing STC SH568NE affects the retirement 
life of certain parts.
    (e) 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, 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.

    (f) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the helicopter to a location where 
the requirements of this AD can be accomplished.


[[Page 52076]]


    Issued in Fort Worth, Texas, on October 3, 2001.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 01-25696 Filed 10-11-01; 8:45 am]
BILLING CODE 4910-13-P