Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-76C Helicopters

[Federal Register Volume 64, Number 55 (Tuesday, March 23, 1999)]
[Rules and Regulations]
[Pages 13889-13890]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-6977]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-22-AD; Amendment 39-11083; AD 99-07-01]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
(Sikorsky) Model S-76C Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing priority letter 
airworthiness directive (AD), applicable to Sikorsky Model S-76C 
helicopters, that currently requires, before further flight, inserting 
new operating limitations and performance data into the Rotorcraft 
Flight Manual (RFM) which require lower allowable gross weights for 
certain operational conditions. This amendment requires the same 
actions as the priority letter AD, but updates the previously 
referenced RFM's. This amendment is prompted by the discovery that the 
RFM's referenced in the priority letter AD have been revised. The 
actions specified by this AD are intended to provide the correct RFM 
references and to prevent an inability to achieve the published One-
Engine-Inoperative (OEI) performance and subsequent loss of control of 
the helicopter.

DATES: Effective April 7, 1999. Comments for inclusion in the Rules 
Docket must be received on or before May 24, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 99-SW-22-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Wayne Gaulzetti, Aerospace Engineer, 
FAA, Boston Aircraft Certification Office, 12 New England Executive 
Park, Burlington, MA 01803, telephone (781) 238-7156, fax (781) 238-
7199.

SUPPLEMENTARY INFORMATION: On February 18, 1999, the FAA issued AD 99-
05-01, Docket No. 99-SW-18-AD, to require, before further flight, 
inserting new operating limitations and performance data into the RFM 
which require lower allowable gross weights for certain operational 
conditions. That action was prompted by an incident in which the design 
of the engine Hydromechanical Unit (HMU) prevented the fuel metering 
valve from delivering the fuel flow required to obtain 30-second OEI 
performance. That condition, if not corrected, could result in an 
inability to achieve the published OEI performance and subsequent loss 
of the helicopter.
    Since the issuance of that AD, the FAA has discovered that the 
RFM's referenced in the priority letter AD have been revised. The FAA 
is superseding the priority letter AD to eliminate any confusion that 
may arise from referencing RFM's that have been revised.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Sikorsky Model S-76C helicopters of the same 
type design, this AD supersedes AD 99-05-01 to require, before further 
flight, inserting new operating limitations and performance data into 
the RFM which require lower allowable gross weights for certain 
operational conditions. The short compliance time involved is required 
because the previously described critical unsafe condition can 
adversely affect the controllability of the helicopter. Therefore, 
inserting new operating limitations and performance data into the RFM 
is required prior to further flight and this AD must be issued 
immediately.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
    The FAA estimates that 17 helicopters will be affected by this 
proposed AD, that it will take approximately 0.5 work hour to insert 
the pages into the RFM, and that the average labor rate is $60 per work 
hour. Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $510.

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. 99-SW-22-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have substantial direct 
effects on the

[[Page 13890]]

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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD), Amendment 39-11083, to read as follows:

AD 99-07-01  Sikorsky Aircraft Corporation: Amendment 39-11083. 
Docket No. 99-SW-22-AD. Supersedes Priority Letter AD 99-05-01, 
Docket No. 99-SW-18-AD.

    Applicability: Model S-76C helicopters, with Turbomeca Arriel 
2S1 engines with an engine Hydromechanical Unit (HMU), part number 
0.292.92.822.0, 0.292.92.808.0, 0.292.92.813.0, or 0.292.92.828.0, 
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 (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 before further flight, unless accomplished 
previously.
    To prevent an inability to achieve the published One-Engine 
Inoperative performance and subsequent loss of the helicopter, 
accomplish the following:
    (a) Insert the following into the Operating Limitations section 
and Performance Data section, as appropriate, of Rotorcraft Flight 
Manual (RFM) SA 4047-76C-10:
    RFM (Basic), original approval date June 19, 1996, Revision 7, 
dated February 1, 1999;
    RFM Supplement No. 8, original approval date August 28, 1997, 
Revision 1, dated February 1, 1999; and
    RFM Supplement No. 9, original approval date August 28, 1997, 
Revision 1, dated February 1, 1999.
    (b) This AD revises the Operating Limitations section and 
Performance Data section of the RFM by requiring lower allowable 
gross weights for certain operational conditions.
    (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 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 
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.
    (e) This amendment becomes effective on April 7, 1999.

    Issued in Fort Worth, Texas, on March 12, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-6977 Filed 3-22-99; 8:45 am]
BILLING CODE 4910-13-U