[Federal Register Volume 60, Number 73 (Monday, April 17, 1995)]
[Rules and Regulations]
[Pages 19157-19158]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-8823]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-46-AD; Amendment 39-9197; AD 95-08-08]


Airworthiness Directives; Boeing Model 737-200 and -200C 
Airplanes Equipped With dB Partners Hush Kits Installed in Accordance 
With Supplemental Type Certificate (STC) SA5730NM

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 737-200 and -200C airplanes. This 
action requires installation of fail-safe straps onto the existing 
engine inlet attach ring of the nose cowl. This amendment is prompted 
by reports of failure of reworked turbine blades, and subsequent 
failure of the engine inlet attach ring. The actions specified in this 
AD are intended to prevent separation of the nose cowl from the engine 
following turbine failure.

DATES: Effective May 2, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 2, 1995.
    Comments for inclusion in the Rules Docket must be received on or 
before June 16, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-46-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
The Nordam Group, 624 East 4th Street, Tulsa, Oklahoma 74120. This 
information may be examined at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Thomas Rodriguez, Aerospace Engineer, 
Airframe Branch, ANM-120S, Seattle Aircraft Certification Office, FAA, 
Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, 
Washington; telephone (206) 227-2779; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: Recently, the FAA has received reports of 
failure of reworked turbine blades on certain Boeing Model 737-200 and 
-200C airplanes. Investigation revealed that dB Partners had installed 
hush kits on these airplanes in accordance with Supplemental Type 
Certificate (STC) SA5730NM. As part of that installation, a re-spaced 
inlet guide vane (RIGV), which is five inches longer than the original 
Boeing inlet, was installed in accordance with the STC. As a result of 
a turbine blade failure, this longer RIGV, which is attached to the 
engine by an attach ring, could separate from the airplane during 
flight. This condition, if not corrected, could result in damage to 
other airplane structure or injury to persons or property on the 
ground.
    The FAA has reviewed and approved Nordam Service Bulletin SB 71-03, 
dated March 17, 1995, which describes procedures for installation of 
eight fail-safe straps onto the existing attach rings of the nose cowl.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to prevent separation of the nose cowl from the engine 
following turbine failure. This AD requires installation of fail-safe 
straps onto the existing attach ring. The actions are required to be 
accomplished in accordance with the service bulletin described 
previously.
    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this rule to clarify this long-standing requirement.
    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.

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 shall 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 
[[Page 19158]] 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 Number 95-NM-46-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, 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

95-08-08 Boeing: Amendment 39-9197. Docket 95-NM-46-AD.

    Applicability: Model 737-200 and -200C airplanes equipped with 
dB Partners Hush Kit installed in accordance with Supplemental Type 
Certificate (STC) SA5730NM, certificated in any category.

    Note 1: This AD applies to each airplane 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 airplanes 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 airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent separation of the nose cowl from the engine following 
turbine blade failure, accomplish the following:
    (a) Within 30 days after the effective date of this AD, install 
fail-safe straps onto the existing attach ring, in accordance with 
Nordam Service Bulletin SB 71-03, dated March 17, 1995.
    (b) As of the effective date of this AD, fail-safe straps must 
be installed onto the existing attach ring of the nose cowl, in 
accordance with Nordam Service Bulletin SB 71-03, dated March 17, 
1995, prior to installation of STC SA5730NM on any airplane.
    (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, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be accomplished.
    (e) The installation shall be done in accordance with Nordam 
Service Bulletin SB 71-03, dated March 17, 1995. 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 The Nordam Group, 624 East 4th Street, Tulsa, Oklahoma 
74120. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.
    (f) This amendment becomes effective on May 2, 1995.

    Issued in Renton, Washington, on April 5, 1995.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-8823 Filed 4-14-95; 8:45 am]
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