[Federal Register Volume 67, Number 119 (Thursday, June 20, 2002)]
[Proposed Rules]
[Pages 41875-41877]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-15551]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-SW-59-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) for Sikorsky Aircraft Corporation Model S-76A, S-76B and 
S-76C helicopters. The AD would require removing and inspecting each 
main rotor spindle attachment bolt (bolt) to ensure that the correct 
bolts are installed. This proposal is prompted by the discovery of 
improper bolts installed on a helicopter during its production. The 
actions specified by the proposed AD are intended to detect 
installation of incorrect bolts, which could result in reduced hub or 
bolt fatigue life, separation of the main rotor blade at the spindle 
attachment, and subsequent loss of control of the helicopter.

DATES: Comments must be received on or before August 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2001-SW-59-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: Kirk Gustafson, Aviation Safety 
Engineer, Boston Aircraft Certification Office, Engine and Propeller 
Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803, 
telephone (781) 238-7190, fax (781) 238-7170.

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

[[Page 41876]]

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, both before and after the closing 
date for comments, 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. 2001-SW-59-AD.'' The postcard will be date 
stamped and returned to the commenter.

Discussion

    This document proposes the adoption of a new AD for Sikorsky 
Aircraft Corporation Model S-76A, S-76B and S-76C helicopters. The AD 
would require removing and inspecting each bolt to ensure that the 
correct bolts are installed. The bolt's complete part number is not 
visible, so it is necessary to measure each bolt to ensure the proper 
length bolt is installed. This proposal is prompted by the discovery of 
improper length bolts installed on a helicopter during its production. 
The manufacturer conducted subsequent inspections of additional 
helicopters, as well as structural assessments on spindle/hub 
attachments. A total of four helicopters were found to have incorrect 
bolts installed. The actions specified by the proposed AD are intended 
to detect installation of incorrect bolts, which could result in 
reduced hub or bolt fatigue life, separation of the main rotor blade at 
the spindle attachment, and subsequent loss of control of the 
helicopter.
    The FAA has reviewed Sikorsky Aircraft Corporation Alert Service 
Bulletin No. 76-65-52 (321), dated July 24, 2001, which describes 
procedures for a one-time inspection of each bolt for the correct 
length during the 1,250 hour time-in-service (TIS) inspection.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, the proposed AD would 
require removing and inspecting each bolt to ensure that the correct 
bolts are installed.
    The FAA estimates that 165 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 6 work 
hours per helicopter to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $240 per helicopter. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators is estimated to be 
$99,000, assuming all 40 bolts (per helicopter) are replaced.
    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 adding a new airworthiness directive 
to read as follows:

Sikorsky Aircraft Corporation: Docket No. 2001-SW-59-AD.

    Applicability: Model S-76A, S-76B and S-76C helicopters, except 
those having a serial number of 760501, or 760506 through 760515, 
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 1,250-hour time-in-service or two 
years, whichever comes first, unless accomplished previously.
    To detect installation of an incorrect main rotor spindle 
attachment bolt (bolt), which could result in reduced hub or bolt 
fatigue life, separation of the main rotor blade at the spindle 
attachment, and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Remove and measure each bolt to ensure that the length is 
1.181 .015 inches. There are 10 bolts per rotor spindle 
and 40 bolts per helicopter that require inspection.
    (1) If 1 or 2 bolts are found on any spindle that are longer 
than 1.196 inches (1.181 inches + .015-inch permissible tolerance), 
visually inspect the main rotor hub internal threads for distortion 
and the hole-bottoms for scoring.
    (i) If thread distortion or hole-bottom scoring is found, remove 
the rotor hub from service.
    (ii) If no thread distortion or hole-bottom scoring is found, 
replace all 10 bolts with new airworthy bolts.
    (2) If 3 or more bolts that exceed 1.196 inches are found on any 
spindle, remove and replace the main rotor hub with an airworthy 
main rotor hub.
    (3) If any bolt is found that is shorter than 1.166 inches 
(1.181 inches-.015 permissible tolerance), replace it with a new 
airworthy bolt.
    (b) Report the results of the inspections of the main rotor hubs 
whenever the bolts exceed 1.196 inches in length, within 5 calendar 
days of the inspection, to the Manager, Boston Aircraft 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone: (781) 
238-7150; fax: (781) 238-7170. Include the following information in 
the report:
    (1) Serial number of the helicopter.
    (2) Quantity of incorrect bolts.
    (3) Description of thread distortion or hole-bottom scoring 
caused by each bolt. Information collection requirements contained 
in this AD have been approved by the Office of Management and Budget 
(OMB) under the provisions of the Paperwork Reduction Act of 1980 
(44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 
2120-0056.

[[Page 41877]]

    (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, Engine and Propeller Directorate, 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.

    (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.

    Issued in Fort Worth, Texas, on June 10, 2002.
Larry M. Kelly,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 02-15551 Filed 6-19-02; 8:45 am]
BILLING CODE 4910-13-P