Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76 Series Helicopters

[Federal Register Volume 65, Number 159 (Wednesday, August 16, 2000)]
[Rules and Regulations]
[Pages 49903-49905]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-20502]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-SW-26-AD; Amendment 39-11861; AD 2000-11-52]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76 Series 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) 2000-11-52, which was sent 
previously to all known U.S. owners and operators of Sikorsky Aircraft 
Corporation (Sikorsky) Model S-76 series helicopters by individual 
letters. This AD requires determining the serial number (S/N) of each 
main rotor blade and removing certain serial numbered main rotor 
blades. This AD also requires visually inspecting and replacing, if 
necessary, other certain serial numbered main rotor blades. This AD is 
prompted by a report of a crack in a main rotor blade and three reports 
of root end pocket separation from main rotor blades during flight. The 
crack and the main rotor blade root end pocket separation were due to 
improper manufacture of certain main rotor blade skins. The actions 
specified by this AD are intended to prevent main rotor blade root end 
pocket separation, impact with main rotor or tail rotor blades, and 
subsequent loss of control of the helicopter.

DATES: Effective August 31, 2000, to all persons except those persons 
to whom it was made immediately effective by Emergency AD 2000-11-52, 
issued on May 26, 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 August 31, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before October 16, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2000-SW-26-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, 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: 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 May 26, 2000, the FAA issued Emergency AD 
2000-11-52, for Sikorsky Model S-76 series helicopters, which requires 
determining the S/N of each main rotor blade and removing certain 
serial numbered main rotor blades. The AD also requires visually 
inspecting and replacing, if necessary, other certain serial numbered 
main rotor blades. That action was prompted by a report of a 20-inch 
crack in the root end pocket of a main rotor blade and three reports of 
root end pocket separation of 4 to 6 foot sections of main rotor blades 
during flight. The crack and the main rotor blade root end pocket 
separation were due to improper manufacture of certain main rotor blade 
skins. This condition, if not corrected, could result in a root end 
pocket separating and impacting a main rotor or tail rotor blade and

[[Page 49904]]

subsequent loss of control of the helicopter.
    The FAA has reviewed Sikorsky Aircraft Corporation Alert Service 
Bulletin No. 76-65-50, dated May 25, 2000 (ASB), which identifies 
certain serial-numbered main rotor blades that need to be removed from 
service. The ASB also describes performing a visual inspection, 
implementing a recurring visual inspection of certain serial-numbered 
main rotor blades for span-wise skin cracks, and removing any main 
rotor blade with a span-wise crack from service before further flight.
    Since the unsafe condition described is likely to exist or develop 
on other Sikorsky Model S-76 series helicopters of the same type 
design, the FAA issued Emergency AD 2000-11-52 to prevent main rotor 
blade root end pocket separation, impact with main rotor or tail rotor 
blades, and subsequent loss of control of the helicopter. The AD 
requires, before further flight, determining the S/N of each main rotor 
blade and accomplishing the following actions in accordance with the 
ASB described previously:
    <bullet> Remove any main rotor blade identified by S/N in Group 1 
of the ASB Planning Information before further flight.
    <bullet> Before each flight and at intervals not to exceed 3 hours 
time-in-service, visually inspect any main rotor blade identified by S/
N in Group 2 of the ASB Planning Information for a span-wise crack in 
the upper and lower root end area. Remove any main rotor blade with a 
span-wise crack and replace it with an airworthy blade before further 
flight.
    Any blade repaired in accordance with Sikorsky Aircraft Corporation 
Overhaul and Repair Instructions (ORI) No. 76150-023, Revision A, dated 
May 26, 2000, is not affected by the requirements of this AD. 
Accomplishing ORI 76150-023, Revision A, dated May 26, 2000, on each 
affected blade is terminating action for the requirements of this AD. 
The short compliance time involved is required because the previously 
described critical unsafe condition can adversely affect the structural 
integrity of the helicopter. Therefore, the actions listed previously 
are required before further flight, and this AD must be issued 
immediately.
    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 May 26, 2000, to all known U.S. owners and operators of 
Sikorsky Model S-76 series 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 167 helicopters of U.S. registry will be 
affected by this AD. It will take approximately 10 work hours to 
replace each main rotor blade, if necessary, and 4 work hours per 
helicopter to inspect the main rotor blades. The average labor rate is 
$60 per work hour. Required parts will cost approximately $99,651 per 
helicopter (assuming replacement of all 4 blades). Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $4,248,480 ($40,080 to inspect the fleet and $4,208,400 to 
replace all main rotor blades on 25 percent of the U.S. 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-26-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:

2000-11-52  Sikorsky Aircraft Corporation: Amendment 39-11861. 
Docket No. 2000-SW-26-AD.

    Applicability: Model S-76 series 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

[[Page 49905]]

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 main rotor blade root end pocket separation, impact 
with main rotor or tail rotor blades, and subsequent loss of control 
of the helicopter, accomplish the following:
    (a) Before further flight, determine the serial number of each 
main rotor blade.
    (b) Any main rotor blade identified in paragraphs (c) or (d) of 
this AD that has been repaired in accordance with Sikorsky Aircraft 
Corporation Overhaul and Repair Instructions (ORI) No. 76150-023, 
Revision A, dated May 26, 2000, and marked as RS-023-1 is not 
affected by the requirements of this AD.
    (c) Before further flight, remove any main rotor blade 
identified by serial number (S/N) in the Group 1, paragraph 1.A. 
Planning Information of Sikorsky Aircraft Corporation Alert Service 
Bulletin No. 76-65-50, dated May 25, 2000 (ASB).
    (d) Before each flight and at intervals not to exceed 3 hours 
time-in-service, visually inspect any main rotor blade, identified 
by S/N in Group 2, paragraph 1.A. of the ASB Planning Information, 
for a span-wise crack in the upper and lower root end area, in 
accordance with paragraph 3.B. of the ASB Accomplishment 
Instructions. Remove any main rotor blade with a span-wise crack and 
replace with an airworthy blade before further flight.
    (e) Accomplishing ORI 76150-023, Revision A, dated May 26, 2000, 
on each affected blade is terminating action for the requirements of 
this AD.

    Note 2: A crack, other than a span-wise crack, in the root end 
cap of the main rotor blade should be dispositioned in accordance 
with the applicable Maintenance Manual.

    (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 removal of certain serial numbered main rotor blades 
shall be done in accordance with Group 1, paragraph 1.A. Planning 
Information of Sikorsky Aircraft Corporation Alert Service Bulletin 
No. 76-65-50, dated May 25, 2000. The visual inspection shall be 
done in accordance with paragraph 3.B. of the Accomplishment 
Instructions of Sikorsky Aircraft Corporation Alert Service Bulletin 
No. 76-65-50, dated May 25, 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, 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.
    (i) This amendment becomes effective on August 31, 2000, to all 
persons except those persons to whom it was made immediately 
effective by Emergency AD 2000-11-52, issued May 26, 2000, which 
contained the requirements of this amendment.

    Issued in Fort Worth, Texas, on August 7, 2000.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-20502 Filed 8-15-00; 8:45 am]
BILLING CODE 4910-13-P

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