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

[Federal Register Volume 66, Number 87 (Friday, May 4, 2001)]
[Rules and Regulations]
[Pages 22431-22432]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-10730]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-SW-40-AD; Amendment 39-12216; AD 94-14-20 R1]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment revises an existing airworthiness directive 
(AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A 
helicopters. That AD currently requires a one-time inspection of the 
tail rotor blade (blade) spar elliptical centering plug (centering 
plug) for disbonding and the addition of a retaining pad on the pitch 
change shaft between the output tail rotor gearbox flange and the 
inboard tail rotor spar. This amendment contains the same requirements 
as the existing AD but clarifies that the 500-hour time-in-service 
(TIS) repetitive inspections, which could cause inadvertent damage, are 
not required. This AD also incorporates by reference a revised alert 
service bulletin (ASB) that does not include the 500-hour TIS 
repetitive inspections. This amendment is prompted by operator 
confusion about whether the current AD continues to require the 500-
hour TIS repetitive inspections. The actions specified by this AD are 
intended to verify that the FAA has determined that the 500-hour TIS 
repetitive inspections are not required to prevent the centering plug 
from disbonding and moving out of position, loss of tail rotor control, 
and subsequent loss of control of the helicopter.

DATES: Effective June 8, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 8, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial 
Tech Support, 6900 Main Street, Stratford, Connecticut 06614, phone 
(203) 386-3001, fax (203) 386-5983. This 1 information may be examined 
at the FAA, Office of the Regional Counsel, Southwest Region, 2601 
Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by revising AD 94-14-20, 
Amendment 39-8969 (59 FR 41238, August 11, 1994), which applies to 
Sikorsky Model S-76A helicopters, was published in the Federal Register 
on January 30, 2001 (66 FR 8184). The action proposed to require a one-
time inspection of the blade centering plug for disbonding and the 
addition of a retaining pad on the pitch change shaft between the 
output tail rotor gearbox flange and the inboard tail rotor spar. The 
action also clarified that 500-hour TIS repetitive inspections, which 
could cause inadvertent damage, are not required and proposed to 
incorporate by reference a revised ASB that does not include the 500-
hour TIS repetitive inspections.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed except for some editorial changes that 
are made in paragraphs (a) and (e). These changes were made to better 
identify the service information that is incorporated by reference. The 
FAA has determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.
    The FAA estimates that this AD will affect 150 helicopters of U.S. 
registry. This revised AD will not impose any additional burden or 
costs.
    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (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); 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 39-8969 (59 FR 
41238, August 11, 1994), and by adding a new airworthiness directive 
(AD), Amendment 39-12216, to read as follows:

94-14-20 R1  Sikorsky Aircraft Corporation: Amendment 39-12216. 
Docket No. 2000-SW-40-AD. Revises AD 94-14-20, Amendment 39-8969, 
Docket No. 93-SW-13-AD.

    Applicability: Model S-76A helicopters, with tail rotor blade 
(blade) assembly, part number (P/N) 76101-05001 (all dash numbers) 
or 76101-05101 (all dash numbers), installed with more than 130

[[Page 22432]]

hours time-in-service (TIS), 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 (c) 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 within 25 hours TIS, unless accomplished 
previously.
    To prevent the blade spar elliptical centering plug (centering 
plug) from disbonding and moving out of position, loss of tail rotor 
control, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Inspect the centering plug for disbonding of the 
polyurethane filler that fills the space between the aluminum 
centering plug and the graphite spar in accordance with the 
Accomplishment Instructions, paragraph 3.A.(1) and (2), of Sikorsky 
Aircraft Corporation Alert Service Bulletin No. 76-65-35B (153B), 
Revision B, dated October 2, 1997 (ASB).

    Note 2: The 500-hours TIS repetitive inspections contained in 
the Accomplishment Instructions, paragraph 3.D., of Sikorsky 
Aircraft Corporation Alert Service Bulletin 76-65-35A, Revision A, 
dated February 29, 1984, are not required by this AD.

    (1) If the inspection of the centering plug reveals disbonding 
of \1/2\-inch or less in length, install a retaining pad, P/N 76102-
05004-111, in accordance with the Accomplishment Instructions, 
paragraph 3.C., of the ASB.
    (2) For disbonds greater than \1/2\-inch in length, repair the 
blade assembly in accordance with the Accomplishment Instructions, 
paragraph 3.B.(1), of the ASB except you are not required to contact 
Sikorsky Worldwide Customer Service. If blades are found with 
polyurethane filler excessively cracked or deteriorated to extent of 
breaking away from the spar or aluminum plug by 0.005-inch or 
greater, replace the blade with an airworthy blade.
    (3) For spars with complete spar to centering plug disbond in 
which the polyurethane filler is intact and remains fully bonded to 
the centering plug, repair the blade assembly in accordance with the 
Accomplishment Instructions, paragraph 3.B.(2), of the ASB.
    (4) For spars with complete polyurethane filler to centering 
plug disbond in which the polyurethane filler is intact and remains 
fully bonded to the spar, repair the blade assembly in accordance 
with the Accomplishment Instructions, paragraph 3.B.(3) of the ASB.
    (b) Install a retaining pad, P/N 76102-05004-111, in accordance 
with the Accomplishment Instructions, paragraph 3.C., of the ASB.
    (c) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Boston Aircraft Certification Office.

    (d) 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 if a retaining pad 
has been installed.
    (e) The inspections, modifications, and repair shall be done in 
accordance with the Accomplishment Instructions, paragraphs 3.A.(1), 
3.A.(2), 3.B.(1), 3.B.(2), 3.B.(3), and 3.C., of Sikorsky Aircraft 
Corporation Alert Service Bulletin No. 76-65-35B (153B), Revision B, 
dated October 2, 1997. This incorporation by reference was approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Copies may be obtained from Sikorsky 
Aircraft Corporation, Attn: Manager, Commercial Tech Support, 6900 
Main Street, Stratford, Connecticut 06614, phone (203) 386-3001, fax 
(203) 386-5983. Copies may be inspected at the FAA, Office of the 
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on June 8, 2001.

    Issued in Fort Worth, Texas, on April 20, 2001.
Larry M. Kelly,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 01-10730 Filed 5-3-01; 8:45 am]
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