AD Amdt-39-11317

[Federal Register Volume 64, Number 180 (Friday, September 17, 1999)]
[Rules and Regulations]
[Pages 50442-50443]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 99-23959]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-44-AD; Amendment 39-11317; AD 99-19-30]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corp. Model S76A, B, 
and C Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) 
applicable to Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, 
and C helicopters. This action requires conducting a visual inspection 
to detect disbonding of the attachment angle between the tail gearbox 
forward fairing (fairing) and the pylon and replacing or repairing the 
attachment angles as necessary. This amendment is prompted by 
incidents, two in flight and eight on the ground, of fairing bonding 
failures. The actions specified in this AD are intended to prevent 
separation of the fairing, damage to the tail rotor blades, and 
subsequent loss of control of the helicopter.

DATES: Effective October 4, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 4, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before November 16, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 99-SW-44-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.
    The service information referenced in this AD may be obtained from 
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Tech Support, 
6900 Main Street, P. O. Box 9729, Stratford, Connecticut 06497-9129, 
phone (203) 386-7860, fax (203) 386-4703. This 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: Jeffrey Lee, Aerospace Engineer, 
Boston Aircraft Certification Office, 12 New England Executive Park, 
Burlington, MA 01803, telephone (781) 238-7161, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: This amendment adopts a new airworthiness 
directive (AD) applicable to Sikorsky Model S-76A, B, and C 
helicopters. This action requires, within 50 hours time-in-service 
(TIS), conducting a visual inspection for disbonding on any attachment 
angle between the fairing and the pylon. Thereafter, a visual 
inspection is required at intervals not to exceed 1500 hours TIS. If a 
bonding failure of one square inch or larger is found on the attachment 
angle, this AD requires repairing or replacing the attachment angle. 
This amendment is prompted by incidents, two in flight and eight on the 
ground, of fairing bonding failures. The actions specified in this AD 
are intended to prevent a separation of the fairing, damage to the tail 
rotor blades, and subsequent loss of control of the helicopter.
    The FAA has reviewed Sikorsky Alert Service Bulletin 76-55-16, 
dated May 12, 1999 (ASB), which describes procedures for inspecting for 
disbonding on the attachment angle between the fairing and the pylon 
and either repairing or replacing, as necessary, the attachment angle. 
The ASB also describes a recurring 1500-hour TIS inspection.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Sikorsky Model S-76A, B, and C helicopters of 
the same type design, this AD is being issued to prevent separation of 
the fairing, damage to the tail rotor blades, and subsequent loss of 
control of the helicopter. This AD requires visually inspecting the 
attachment angle on each fairing for disbonding and repairing or 
replacing the attachment angle as appropriate. The actions are required 
to be accomplished in accordance with the ASB described previously. The 
short compliance time involved is required because the previously 
described critical unsafe condition can adversely affect the structural 
integrity of the helicopter. Therefore, visually inspecting the 
attachment angle on each fairing for disbonding and repairing or 
replacing the attachment angle, as appropriate, within 50 hours TIS, is 
required and this AD must be issued immediately.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
    The FAA estimates that 150 helicopters will be affected by this AD, 
that it will take approximately 4 work hours to accomplish the 
inspection and 8 work hours to replace the attachment angle. The 
average labor rate is $60 per work hour. Required parts will cost 
approximately $880 per helicopter. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $240,000.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments

[[Page 50443]]

submitted will be available, both before and after the closing date for 
comments, in the Rules Docket for examination by interested persons. A 
report that summarizes each FAA-public contact concerned with the 
substance of this AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: Comments to 
Docket No. 99-SW-44-AD. The postcard will be date stamped and returned 
to the commenter.
    The regulations adopted herein will not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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 adding a new airworthiness directive 
to read as follows:

AD 99-19-30  Sikorsky Aircraft Corporation: Amendment 39-11317. 
Docket No. 99-SW-44-AD.

    Applicability: Model S-76A, B, and C 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 (d) 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 separation of the tail gearbox forward fairing 
(fairing), damage to the tail rotor blades, and subsequent loss of 
control of the helicopter, accomplish the following:
    (a) Within 50 hours time-in-service (TIS), conduct a visual 
inspection of the attachment angle on each fairing, in accordance 
with the Accomplishment Instructions, paragraph A, of Sikorsky 
Aircraft Corp. Alert Service Bulletin 76-55-16, dated May 12, 1999 
(ASB).
    (b) Thereafter, at intervals not to exceed 1500 hours TIS, 
conduct a visual inspection of the attachment angle on each fairing 
in accordance with the Accomplishment Instructions, paragraph A, of 
the ASB.
    (c) If the visual inspection in paragraphs (a) or (b) reveals a 
disbond area that equals or exceeds 1.0 square inch, prior to 
further flight, repair or replace the attachment angle with an 
airworthy attachment angle in accordance with the Accomplishment 
Instructions, paragraph B, of the ASB.
    (d) 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. 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.

    (e) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the helicopter to a location where 
the requirements of this AD can be accomplished.
    (f) The inspection, repair, or replacement shall be done in 
accordance with the Accomplishment Instructions in Sikorsky Aircraft 
Corp. Alert Service Bulletin 76-55-16, dated May 12, 1999. 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, P. O. Box 9729, 
Stratford, Connecticut 06497-9129, phone (203) 386-7860, fax (203) 
386-4703. 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.
    (g) This amendment becomes effective on October 4, 1999.

    Issued in Fort Worth, Texas, on September 7, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-23959 Filed 9-16-99; 8:45 am]
BILLING CODE 4910-13-U