Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters

[Federal Register Volume 64, Number 10 (Friday, January 15, 1999)]
[Rules and Regulations]
[Pages 2560-2562]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-907]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-37-AD; Amendment 39-10999; AD 98-17-15]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76A, B, and C Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) 98-17-15 which was sent 
previously to all known U.S. owners and operators of Sikorsky Aircraft 
Corporation Model S-76A, B, and C helicopters by individual letters. 
This AD requires, before further flight, a one-time visual inspection 
of the swashplate assembly uniball bearing

[[Page 2561]]

retainer (retainer) for missing bolts, an inspection with a magnet to 
detect aluminum bolts, and replacing missing or aluminum bolts with 
airworthy steel bolts. This amendment is prompted by reports of the 
installation of aluminum bolts on swashplate assemblies. This 
condition, if not corrected, could result in failure of the swashplate 
assembly, loss of the main rotor, and subsequent loss of control of the 
helicopter.

DATES: Effective February 1, 1999, to all persons except those persons 
to whom it was made immediately effective by Priority Letter AD 98-17-
15, issued on August 13, 1998, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before March 16, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-37-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Robert Mann, Aerospace Engineer, FAA, 
Boston Aircraft Certification Office, ANE-150, 12 New England Executive 
Park, Burlington, Massachusetts 01803, telephone (781) 238-7190, fax 
(781) 238-7199.

SUPPLEMENTARY INFORMATION: On August 13, 1998, the FAA issued Priority 
Letter AD 98-17-15, applicable to Sikorsky Aircraft Corporation Model 
S-76A, B, and C helicopters, which requires, before further flight, a 
one-time visual inspection of the swashplate assembly retainer for 
missing bolts and a one-time inspection of each retainer bolt using a 
magnet to detect the installation of aluminum retainer bolts. If 
retainer bolts are missing or aluminum bolts are found, the AD requires 
that they be replaced with airworthy steel bolts. That action was 
prompted by reports of the installation of aluminum bolts on swashplate 
assemblies, part numbers 76104-08000-044, -045, -046, and 76104-08500-
041 and -043. This condition, if not corrected, could result in failure 
of the swashplate assembly, loss of control of the main rotor, and 
subsequent loss of control of the helicopter.
    The FAA has reviewed Sikorsky Aircraft Corporation Service Bulletin 
76-65-47, dated July 31, 1998 (SB). The SB describes procedures for a 
one-time visual inspection of the swashplate assembly retainer for 
missing bolts, an inspection with a magnet to determine whether steel 
bolts are installed, and replacing missing or aluminum bolts with 
airworthy steel bolts.
    Since the unsafe condition described is likely to exist or develop 
on other Sikorsky Aircraft Corporation Model S-76A, B, and C 
helicopters of the same type design, the FAA issued Priority Letter AD 
98-17-15 to prevent failure of the swashplate assembly, loss of the 
main rotor, and subsequent loss of control of the helicopter. The AD 
requires, before further flight, a one-time visual inspection of the 
swashplate assembly retainer for missing bolts, an inspection with a 
magnet to detect aluminum bolts, and replacing missing or aluminum 
bolts with airworthy steel bolts.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on August 13, 1998 to all known U.S. owners and operators of 
Sikorsky Aircraft Corporation Model S-76A, B, and C helicopters. These 
conditions still exist, and the AD is hereby published in the Federal 
Register as an amendment to section 39.13 of the Federal Aviation 
Regulations (14 CFR 39.13) to make it effective to all persons.
    The FAA estimates that 157 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 3 work hours per 
helicopter to accomplish the required actions, and that the average 
labor rate is $60 per work hour. Required parts will cost approximately 
$3 per swashplate assembly. Based on these figures, the total cost 
impact of the AD on U.S. operators is estimated to be $28,731, assuming 
one inspection and replacement of all retainer bolts in all the 
helicopters.

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 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. 98-SW-37-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, 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:

[[Page 2562]]

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 98-17-15  Sikorsky Aircraft Corporation: Amendment 39-10999. 
Docket No. 98-SW-37-AD.

    Applicability: Model S-76A, B, and C helicopters, serial numbers 
prior to 760488, with swashplate assembly, part numbers 76104-08000-
044, -045, -046, or 76104-08500-041 or -043, installed, certificated 
in any category.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability provision, regardless of whether it has been 
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 use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition, or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any helicopter from the applicability of this AD.

    Compliance: Required before further flight, unless accomplished 
previously.
    To prevent failure of the swashplate assembly, loss of control 
of the main rotor, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Conduct a one-time visual inspection of the swashplate 
assembly uniball bearing retainer (retainer) to determine whether 
any retainer bolts are missing. Replace any missing retainer bolt 
with an airworthy AN3-5A bolt.
    (b) Conduct a one-time inspection of each swashplate assembly 
retainer bolt (12 installed) with a magnet to verify that a steel 
bolt is installed. The steel bolts will attract the magnet, the 
aluminum bolts will not. Replace any aluminum bolt, one at a time, 
with an airworthy AN3-5A bolt.

    Note 2: Sikorsky Aircraft Corporation Service Bulletin 76-65-47, 
dated July 31, 1998, pertains to the subject of this AD.

    (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 will not be issued.
    (e) This amendment becomes effective on February 1, 1999, to all 
persons except those persons to whom it was made immediately 
effective by Priority Letter AD 98-17-15, issued August 13, 1998, 
which contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on January 7, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-907 Filed 1-14-99; 8:45 am]
BILLING CODE 4910-13-P

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