Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

[Federal Register Volume 70, Number 31 (Wednesday, February 16, 2005)]
[Rules and Regulations]
[Pages 7851-7853]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-2832]



[[Page 7851]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19447; Directorate Identifier 2004-NM-97-AD; 
Amendment 39-13976; AD 2005-04-04]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B 
Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Saab Model SAAB SF340A and SAAB 340B series airplanes. This AD requires 
a one-time inspection to determine the part and serial numbers of 
certain engine vibration isolators (mounts) and the cure dates of 
certain molded assemblies incorporated in those engine mounts; and 
related corrective actions if necessary. This AD is prompted by a 
report that disbonding of the elastomer from the inner metal core and 
shim of certain engine vibration mounts has occurred within a few 
hundred hours of operation, causing heavy chafing of the engine support 
system and chafing of the fire sensor loop. We are issuing this AD to 
prevent reduced integrity of the fire-shielding capacity of the nacelle 
structure and a possible fire detector fault.

DATES: This AD becomes effective March 23, 2005.
    The incorporation by reference of a certain publication listed in 
the AD is approved by the Director of the Federal Register as of March 
23, 2005.

ADDRESSES: For service information identified in this AD, contact Saab 
Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linkping, Sweden.
    You can examine this information at the National Archives and 
Records Administration (NARA). For information on the availability of 
this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    Docket: The AD docket contains the proposed AD, comments, and any 
final disposition. You can examine the AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility 
office between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the U.S. 
Department of Transportation, 400 Seventh Street SW., room PL-401, 
Washington, DC. This docket number is FAA-2004-19447; the directorate 
identifier for this docket is 2004-NM-97-AD.

FOR FURTHER INFORMATION CONTACT: Mike Borfitz, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2677; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR Part 39 
with an AD for all Saab Model SAAB SF340A and SAAB 340B series 
airplanes. That action, published in the Federal Register on October 
27, 2004 (69 FR 62625), proposed to require a one-time inspection to 
determine the part and serial numbers of certain engine vibration 
isolators (mounts) and the cure dates of certain molded assemblies 
incorporated in those engine mounts; and related corrective actions if 
necessary.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comment that has been 
submitted on the proposed AD.

Request To Withdraw Proposed AD

    The commenter requests that the proposed AD be withdrawn. The 
commenter states that delamination of a bonded canister (molded 
assembly) is readily apparent and would have been detected during the 
scheduled inspections recommended in the Saab maintenance program. The 
commenter also mentions that the molded assemblies have a life limit of 
5,000 flight hours, at which point those assemblies are removed from 
the airplane. The commenter notes that by the time the proposed AD is 
issued, almost three years would have passed since the affected molded 
assemblies were put into service. The commenter remarks that it is 
unlikely that any affected molded assembly remaining in the field would 
not have already been identified and removed from service during the 
regularly scheduled maintenance inspection program. The commenter 
states that, for the reasons mentioned above, the FAA needs to consider 
the timing of the proposed AD. The commenter suggests that, at this 
late date, the unsafe condition regarding the removal of molded 
assemblies subject to delamination would have resolved itself.
    We do not agree with the commenter's request to withdraw this AD. 
The procedures specified in a service bulletin are not mandatory. 
Therefore, we must issue an AD to ensure that the identified unsafe 
condition is properly addressed. Even if the current U.S.-registered 
fleet is in compliance with the requirements of this AD, the issuance 
of the rule is still necessary to ensure that any affected airplane 
that is imported and placed on the U.S. register in the future will be 
required to be in compliance as well. We also want to ensure that, if 
the subject molded assemblies are currently in an operator's spare 
parts inventory, the actions required by this AD are performed. In 
addition, as provided by paragraph (e) of this AD, operators who have 
already done all of the actions required by this AD are already in 
compliance with this AD, and no further action is required by them. 
Furthermore, the requirements of this AD include a general visual 
inspection for chafing of the nacelle structure and fire sensor loop. 
This inspection is necessary because chafing of the nacelle structure 
and fire sensor loop is part of the unsafe condition addressed by this 
AD. We must ensure that operators did this inspection and did not just 
replace the engine mounts. Also, the airworthiness authority for the 
state of design issued an airworthiness directive mandating the same 
actions required by this AD. No change has been made to this AD 
regarding this issue.

Changes to This AD

    We have added a new paragraph (g), Parts Installation, in this AD 
to clarify that, prior to the installation of an engine vibration mount 
on an airplane, the part and serial number of the engine vibration 
mount, and the cure date of the molded assembly incorporated in the 
engine mount must be determined, and any applicable corrective action 
accomplished before further flight, in accordance with the requirements 
of paragraph (f) of this AD. Although this was our intent in the 
proposed AD, the Parts Installation paragraph was inadvertently omitted 
from the proposed AD. The subsequent paragraphs in this AD have been 
reidentified accordingly.
    Also, for clarification purposes, certain terminology in the 
proposed AD has been changed in this AD. The phrase ``molded assembly 
engine mounts (isolators)'' has been changed to ``engine vibration 
isolators (mounts).'' The term ``bonded canister assemblies''

[[Page 7852]]

has been changed to ``molded assemblies.''

Conclusion

    We have carefully reviewed the available data, including the 
comment that has been submitted, and determined that air safety and the 
public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    This AD affects about 170 airplanes of U.S. registry. The required 
actions will take about 2 work hours per airplane, at an average labor 
rate of $65 per work hour. Based on these figures, the estimated cost 
of this AD for U.S. operators is $22,100 or $130 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD. See the ADDRESSES section for a location to 
examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2005-04-04 SAAB Aircraft AB: Amendment 39-13976. Docket No. FAA-
2004-19447; Directorate Identifier 2004-NM-97-AD.

Effective Date

    (a) This AD becomes effective March 23, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Model SAAB SF340A and SAAB 340B 
series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD was prompted by a report that disbonding of the 
elastomer from the inner metal core and shim of certain engine 
vibration isolators (mounts) has occurred within a few hundred hours 
of operation, causing heavy chafing of the engine support system and 
chafing of the fire sensor loop. We are issuing this AD to prevent 
reduced integrity of the fire-shielding capacity of the engine 
nacelle structure and a possible fire detector fault.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Inspection

    (f) Within 500 flight hours after the effective date of this AD, 
perform a one-time inspection to determine the part and serial 
numbers of certain engine vibration mounts, and the cure dates of 
certain molded assemblies incorporated in those engine mounts; and a 
general visual inspection for chafing of the nacelle structure and 
fire sensor loop; and related corrective actions, as applicable; in 
accordance with the Accomplishment Instructions of Saab Service 
Bulletin 340-71-059, dated May 16, 2003. Corrective actions must be 
accomplished prior to further flight.


    Note 1: Saab Service Bulletin 340-71-059 refers to Barry 
Controls Service Letter 93948-71-05, dated April 30, 2003, as an 
additional source of service information.


    Note 2: For the purposes of this AD, a general visual inspection 
is ``a visual examination of an interior or exterior area, 
installation or assembly to detect obvious damage, failure or 
irregularity. This level of inspection is made from within touching 
distance unless otherwise specified. A mirror may be necessary to 
ensure visual access to all surfaces in the inspection area. This 
level of inspection is made under normal available lighting 
conditions such as daylight, hangar lighting, flashlight or 
droplight and may require removal or opening of access panels or 
doors. Stands, ladders or platforms may be required to gain 
proximity to the area being checked.''

Parts Installation

    (g) As of the effective date of this AD, no person may install 
on any airplane an engine vibration mount unless the part and serial 
number of the engine vibration mount, and the cure date of the 
molded assembly incorporated in the engine mount, have been 
determined and any applicable corrective action accomplished before 
further flight, in accordance with the requirements of paragraph (f) 
of this AD.

Alternative Methods of Compliance (AMOCs)

    (h) The Manager, International Branch, ANM-116, Transport 
Airplane Directorate, FAA, has the authority to approve AMOCs for 
this AD, if requested in accordance with the procedures found in 14 
CFR 39.19.

Related Information

    (i) Swedish airworthiness directive SAD 1-192, dated May 16, 
2003, also addresses the subject of this AD.

Material Incorporated by Reference

    (j) You must use Saab Service Bulletin 340-71-059, dated May 16, 
2003, including Attachment 1, dated April 30, 2003; to perform the 
actions that are required by this AD, unless the AD specifies 
otherwise. The Director of the Federal Register approves the 
incorporation by reference of this document in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. For copies of the service 
information, contact Saab Aircraft AB, SAAB Aircraft Product 
Support, S-581.88, Linkoping, Sweden. For information on the 
availability of this material at the National Archives and Records 
Administration (NARA), call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    You may view the AD docket at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street, SW.,

[[Page 7853]]

room PL-401, Nassif Building, Washington, DC.

    Issued in Renton, Washington, on January 31, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-2832 Filed 2-15-05; 8:45 am]
BILLING CODE 4910-13-P

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