AD 98-17-15

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AD Number:
98-17-15
Document Type:
AD Final Rules
Docket Number:
98-SW-37-AD
Subject Heading:
Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, B, and C Helicopters
Subject:
Swashplate Assembly Uniball Bearing Retainer Inspection
Status:
Current
Citation:
Citation Publish Date:
Effective Date:
02/01/1999
Make:
Sikorsky Aircraft Corporation
Model:
S-76A | S-76B | S-76C
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 [64 FR 2560 NO. 10 01/15/99]
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 98-17-15
CITATION:  

PAGE NUMBER:  

DOCKET NUMBER:   98-SW-37-AD

AMENDMENT:   39-10999

AD NUMBER:   98-17-15

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

ACTION:   Final rule; request for comments

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 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:

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.

§ 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

REGULATORY TEXT:  
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.

FOOTER: