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

[Federal Register Volume 66, Number 22 (Thursday, February 1, 2001)]
[Rules and Regulations]
[Pages 8507-8509]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-2611]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-SW-61-AD; Amendment 39-12095; AD 2000-23-52]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76A, S-76B, and S-76C 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 superseding Airworthiness Directive (AD) 2000-23-52, which was 
sent previously to all known U.S. owners and operators of Sikorsky 
Aircraft Corporation (Sikorsky) Model S-76A, S-76B, and S-76C 
helicopters by individual letters. This AD requires, before further 
flight, performing a fluorescent penetrant inspection of the main rotor 
shaft assembly (shaft). Also required are recurring fluorescent 
penetrant inspections and visual inspections for any crack. If any 
crack is found, the shaft must be replaced with an airworthy shaft 
before further flight. This amendment is prompted by the discovery of 
two in-service cracked shafts, one with 477 hours time-in-service (TIS) 
and one with 313 hours TIS. A third shaft, that had been rejected from 
the manufacturing process for other reasons, was also discovered to 
have a crack. The actions specified by this AD are intended to prevent 
failure of the shaft and subsequent loss of control of the helicopter.

DATES: Effective February 16, 2001, to all persons except those persons 
to whom it was made immediately effective by Emergency AD 2000-23-52, 
issued on November 9, 2000, which contained the requirements of this 
amendment.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 16, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before April 2, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2000-SW-61-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].
    The applicable service information may be obtained from Sikorsky 
Aircraft Corporation, Attn: Manager, Commercial Tech Support, 6900 Main 
Street, Stratford, Connecticut 06614, 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: Wayne Gaulzetti, Aviation Safety 
Engineer, Boston Aircraft Certification Office, 12 New England 
Executive Park, Burlington, MA 01803, telephone (781) 238-7156, fax 
(781) 238-7199.

SUPPLEMENTARY INFORMATION: On November 3, 2000, the FAA issued AD 2000-
23-51, which required a one-time fluorescent penetrant inspection of 
the shaft. That AD was prompted by the discovery of a cracked shaft 
having 477 hours TIS. Since the issuance of that AD, additional 
incidents of cracked shafts occurred, and we determined that additional 
inspections are required. On November 9, 2000, we issued superseding 
Emergency AD 2000-23-52, for Sikorsky Model S-76A, S-76B, and S-76C 
helicopters, which requires an initial and recurring fluorescent 
penetrant inspections of the shaft. Also required, before the first 
flight of each day, are visual inspections for any crack. If any crack 
is found, the shaft must be replaced before further flight with an 
airworthy shaft.
    The FAA has reviewed Sikorsky Aircraft Corporation Alert Service 
Bulletin No. 76-66-31, Revision B, dated November 7, 2000, which 
describes procedures for inspecting the shaft, part number 76351-09030 
series and 76351-09630 series. In addition to requiring the inspections 
prescribed in this alert service bulletin, the FAA has determined that 
certain shafts, part number 76351-09030 series, serial numbers with a 
prefix of ``B'' and numbers 015-00700 through 00706, must be removed 
from service because the three cracked shafts discovered thus far came 
from that manufacturing lot.
    Since the unsafe condition described is likely to exist or develop 
on other Sikorsky Model S-76A, S-76B, and S-76C helicopters of the same 
type designs, the FAA issued superseding Emergency AD 2000-23-52 to 
prevent failure of the shaft and subsequent loss of control of the 
helicopter. The AD requires, before further flight, performing a 
fluorescent penetrant inspection of the shaft in the area above the 
upper shaft output seal and below the lower hub attachment flange. 
Thereafter, recurring fluorescent penetrant inspections are required at 
specified time intervals and visual inspections using a 10 x  or higher 
magnifying glass are required before the first flight of each day. If 
any crack is found, the shaft must be replaced before further flight 
with an airworthy shaft that has been inspected in accordance with the 
requirements of this AD. The actions must be accomplished in accordance 
with the alert service bulletin described previously. The short 
compliance time involved is required because the previously described 
critical unsafe condition can adversely affect the structural integrity 
and controllability of the helicopter. Therefore, the actions stated 
previously are required before further flight and at the specified time 
intervals, and this AD must be issued immediately.
    Since it was found that immediate corrective action was required, 
notice

[[Page 8508]]

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 November 9, 2000, 
to all known U.S. owners and operators of Sikorsky Model S-76A, S-76B, 
and S-76C helicopters. These conditions still exist, and the AD is 
hereby published in the Federal Register as an amendment to 14 CFR 
39.13 to make it effective to all persons. However, there was an error 
in the preamble section of the emergency AD; the superseded AD number 
is 2000-23-51, the emergency AD incorrectly referenced AD 2000-53-21. 
The correction to the superseded AD number is made in this AD; the FAA 
has determined that this change will neither increase the economic 
burden on an operator nor increase the scope of the AD.
    The FAA estimates that 172 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 4 work hours per 
helicopter to accomplish the fluorescent inspection, \1/2\ work hour 
per helicopter to perform each visual inspection, and 8 work hours per 
helicopter to replace the shaft, if necessary, and that the average 
labor rate is $60 per work hour. Required parts, if a shaft needs to be 
replaced, will cost approximately $25,000 per helicopter. Based on 
these figures, the total cost impact of the AD on U.S. operators is 
estimated to be $2,913,680 per year (assuming $41,280 for the initial 
fluorescent inspections; $206,400 for 5 repetitive inspections on each 
helicopter; $516,000 for 100 visual inspections on each helicopter; and 
$2,150,000 to replace the shaft on half of the fleet).

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 mailed 
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. 2000-SW-61-AD.'' The postcard will be date 
stamped and returned to the commenter.
    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.
    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:

2000-23-52  Sikorsky Aircraft Corporation: Amendment 39-12095. 
Docket No. 2000-SW-61-AD. Supersedes Emergency AD 2000-23-51, Docket 
No. 2000-SW-59-AD.

    Applicability: Model S-76A, S-76B, and S-76C helicopters, with 
main rotor shaft assembly (shaft), part number (P/N) 76351-09030 
series or 76351-09630 series, 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 
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 (f) 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 failure of the shaft and subsequent loss of control 
of the helicopter, accomplish the following:
    (a) Before further flight, perform a fluorescent penetrant 
inspection of the shaft in the area above the upper shaft output 
seal and below the lower hub attachment flange for any cracks in 
accordance with the Accomplishment Instructions, paragraphs 3.A.(1) 
through 3.A.(8), contained in Sikorsky Aircraft Corporation Alert 
Service Bulletin No. 76-66-31, Revision B, dated November 7, 2000 
(ASB).

    Note 2: The fluorescent penetrant inspection specified in this 
AD is not the fluorescent penetrant inspection contained in 
paragraph 4 of Chapter 20-05-00 of the applicable maintenance 
manual.

    (b) Before the first flight of each day, visually inspect the 
shaft in the area above the upper shaft output seal and below the 
lower hub attachment flange for any cracks using a 10x or higher 
magnifying glass. Accomplish this inspection in accordance with the 
Accomplishment Instructions, paragraphs 3.B.(1) through 3.B.(5), of 
the ASB, except contacting Sikorsky Aircraft Corporation is not 
required by this AD.
    (c) At intervals not to exceed 20 hours time-in-service or 80 
landings, whichever occurs first, perform a fluorescent penetrant 
inspection of the shaft in the area above the upper shaft output 
seal and below the lower

[[Page 8509]]

hub attachment flange in accordance with the Accomplishment 
Instructions, paragraphs 3.C.(1) through 3.C.(5), of the ASB, except 
contacting Sikorsky Aircraft Corporation is not required by this AD.
    (d) If a crack is found as a result of any of the inspections, 
remove the shaft and replace it with an airworthy shaft that has 
been inspected in accordance with paragraph (a) of this AD before 
further flight.
    (e) Before further flight, shafts, P/N 76351-09030-series, 
serial numbers with a prefix of ``B'' and numbers 015-00700 through 
00706, must be removed from service.
    (f) 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.

    (g) 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.
    (h) The fluorescent penetrant and visual inspections shall be 
done in accordance with the Accomplishment Instructions, paragraphs 
3.A.(1) through 3.A.(8), 3.B.(1) through 3.B.(5), and 3.C.(1) 
through 3.C.(5), contained in Sikorsky Aircraft Corporation Alert 
Service Bulletin No. 76-66-31 (318B), Revision B, dated November 7, 
2000. 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) 386-7860, 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.
    (i) This amendment becomes effective on February 16, 2001, to 
all persons except those persons to whom it was made immediately 
effective by Emergency AD 2000-23-52, issued November 9, 2000, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on January 19, 2001.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 01-2611 Filed 1-31-01; 8:45 am]
BILLING CODE 4910-13-U

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