

[Federal Register: December 10, 2007 (Volume 72, Number 236)]
[Proposed Rules]               
[Page 69635-69637]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10de07-30]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0298; Directorate Identifier 2007-NM-238-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD results from mandatory 
continuing airworthiness information (MCAI) originated by an aviation 
authority of another country to identify and correct an unsafe 
condition on an aviation product. The MCAI describes the unsafe 
condition as:

    Subsequent to accidents involving Fuel Tank System explosions in 
flight * * * and on ground, the FAA has published Special Federal 
Aviation Regulation 88 (SFAR88) * * * [which] required * * * 
[conducting] a design review against explosion risks.

The unsafe condition is the potential of ignition sources inside fuel 
tanks, which, in combination with flammable fuel vapors, could result 
in fuel tank explosions and consequent loss of the airplane. The 
proposed AD would require actions that are intended to address the 
unsafe condition described in the MCAI.

DATES: We must receive comments on this proposed AD by January 9, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov.
 Follow the instructions for submitting comments.

     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-40, 1200 New 
Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov
; or in person at the Docket Operations office 

between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
in the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Shahram Daneshmandi, Aerospace 
Engineer, International Branch, ANM-116, Transport Airplane 
Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; 
telephone (425) 227-1112; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2007-0298; 
Directorate Identifier 2007-NM-238-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD based on those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov
, including any personal information you provide. We 

will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued EASA 
Airworthiness Directive 2007-0168, dated June 15, 2007 (referred to 
after this as ``the MCAI''), to correct an unsafe condition for the 
specified products. The MCAI states:

    Subsequent to accidents involving Fuel Tank System explosions in 
flight * * * and on ground, the FAA has published Special Federal 
Aviation Regulation 88 (SFAR88) in June 2001.
    In their Letters referenced 04/00/02/07/01-L296 dated March 4, 
2002 and 04/00/02/07/03-L024, dated February 3, 2003, the JAA 
recommended the application of a similar regulation to the National 
Aviation Authorities (NAA).

[[Page 69636]]

    Under this regulation, all holders of type certificates for 
passenger transport aircraft with either a passenger capacity of 30 
or more, or a payload capacity of 7,500 pounds (3402 kg) or more, 
which have received their certification since January 1, 1958, are 
required to conduct a design review against explosion risks.
    This Airworthiness Directive (AD), which renders mandatory the 
modification [2762] of improving the sealing of Fuel Access Doors, 
is a consequence of the design review.

The unsafe condition is the potential of ignition sources inside fuel 
tanks, which, in combination with flammable fuel vapors, could result 
in fuel tank explosions and consequent loss of the airplane. 
Modification 2762 includes removing the fuel tank access doors and the 
old type of clamp rings and gaskets, installing new, improved clamp 
rings and re-installing the fuel tank access doors, and doing related 
investigative and applicable corrective actions. Related investigative 
and applicable corrective actions include inspecting for corrosion of 
the wing skin panel, access door areas, and access doors; removing any 
corrosion found during the inspection; and replacing the access door 
protection plate with a new protection plate. Corrosion removal also 
includes inspecting the doubler flange and contacting Saab and doing 
repairs if the doubler flange thickness does not meet minimum 
specifications. Additional corrective actions include replacing 
conductive foil on the access door with an aluminum panel. You may 
obtain further information by examining the MCAI in the AD docket.
    The FAA has examined the underlying safety issues involved in fuel 
tank explosions on several large transport airplanes, including the 
adequacy of existing regulations, the service history of airplanes 
subject to those regulations, and existing maintenance practices for 
fuel tank systems. As a result of those findings, we issued a 
regulation titled ``Transport Airplane Fuel Tank System Design Review, 
Flammability Reduction and Maintenance and Inspection Requirements'' 
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards 
for transport airplanes and new maintenance requirements, this rule 
included Special Federal Aviation Regulation No. 88 (``SFAR 88,'' 
Amendment 21-78, and subsequent Amendments 21-82 and 21-83).
    Among other actions, SFAR 88 requires certain type design (i.e., 
type certificate (TC) and supplemental type certificate (STC)) holders 
to substantiate that their fuel tank systems can prevent ignition 
sources in the fuel tanks. This requirement applies to type design 
holders for large turbine-powered transport airplanes and for 
subsequent modifications to those airplanes. It requires them to 
perform design reviews and to develop design changes and maintenance 
procedures if their designs do not meet the new fuel tank safety 
standards. As explained in the preamble to the rule, we intended to 
adopt airworthiness directives to mandate any changes found necessary 
to address unsafe conditions identified as a result of these reviews.
    In evaluating these design reviews, we have established four 
criteria intended to define the unsafe conditions associated with fuel 
tank systems that require corrective actions. The percentage of 
operating time during which fuel tanks are exposed to flammable 
conditions is one of these criteria. The other three criteria address 
the failure types under evaluation: single failures, single failures in 
combination with a latent condition(s), and in-service failure 
experience. For all four criteria, the evaluations included 
consideration of previous actions taken that may mitigate the need for 
further action.
    The Joint Aviation Authorities (JAA) has issued a regulation that 
is similar to SFAR 88. (The JAA is an associated body of the European 
Civil Aviation Conference (ECAC) representing the civil aviation 
regulatory authorities of a number of European States who have agreed 
to co-operate in developing and implementing common safety regulatory 
standards and procedures.) Under this regulation, the JAA stated that 
all members of the ECAC that hold type certificates for transport 
category airplanes are required to conduct a design review against 
explosion risks.
    We have determined that the actions identified in this AD are 
necessary to reduce the potential of ignition sources inside fuel 
tanks, which, in combination with flammable fuel vapors, could result 
in fuel tank explosions and consequent loss of the airplane.

Relevant Service Information

    Saab has issued Service Bulletin 340-57-031, Revision 02, dated 
September 28, 2005; and Service Bulletin 340-57-010, dated March 28, 
1989. The actions described in this service information are intended to 
correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with the State of Design Authority, we have 
been notified of the unsafe condition described in the MCAI and service 
information referenced above. We are proposing this AD because we 
evaluated all pertinent information and determined an unsafe condition 
exists and is likely to exist or develop on other products of the same 
type design.

Differences Between This AD and the MCAI or Service Information

    We have reviewed the MCAI and related service information and, in 
general, agree with their substance. But we might have found it 
necessary to use different words from those in the MCAI to ensure the 
AD is clear for U.S. operators and is enforceable. In making these 
changes, we do not intend to differ substantively from the information 
provided in the MCAI and related service information.
    We might also have proposed different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a NOTE within the proposed AD.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 168 products of U.S. registry. We also estimate that 
it would take about 20 work-hours per product to comply with the basic 
requirements of this proposed AD. The average labor rate is $80 per 
work-hour. Required parts would cost about $417 per product. Where the 
service information lists required parts costs that are covered under 
warranty, we have assumed that there will be no charge for these costs. 
As we do not control warranty coverage for affected parties, some 
parties may incur costs higher than estimated here. Based on these 
figures, we estimate the cost of the proposed AD on U.S. operators to 
be about $338,856, or about $2,017 per product.

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

[[Page 69637]]

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 determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new AD:

Saab Aircraft AB: Docket No. FAA-2007-0298; Directorate Identifier 
2007-NM-238-AD.

Comments Due Date

    (a) We must receive comments by January 9, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Saab Model SAAB SF340A and Model SAAB 
340B airplanes, certificated in any category, serial numbers 004 
through 401.

Subject

    (d) Air Transport Association (ATA) of America Code 57: Wings.

Reason

    (e) The mandatory continuing airworthiness information (MCAI) 
states:
    Subsequent to accidents involving Fuel Tank System explosions in 
flight * * * and on ground, the FAA has published Special Federal 
Aviation Regulation 88 (SFAR88) in June 2001.
    In their Letters referenced 04/00/02/07/01-L296 dated March 4, 
2002 and 04/00/02/07/03-L024, dated February 3, 2003, the JAA 
recommended the application of a similar regulation to the National 
Aviation Authorities (NAA).
    Under this regulation, all holders of type certificates for 
passenger transport aircraft with either a passenger capacity of 30 
or more, or a payload capacity of 7,500 pounds (3402 kg) or more, 
which have received their certification since January 1, 1958, are 
required to conduct a design review against explosion risks.
    This Airworthiness Directive (AD), which renders mandatory the 
modification [2762] of improving the sealing of Fuel Access Doors, 
is a consequence of the design review.

The unsafe condition is the potential of ignition sources inside 
fuel tanks, which, in combination with flammable fuel vapors, could 
result in fuel tank explosions and consequent loss of the airplane. 
Modification 2762 includes removing the fuel tank access doors and 
the old type of clamp rings and gaskets, installing new, improved 
clamp rings and re-installing the fuel tank access doors, and doing 
related investigative and applicable corrective actions. Related 
investigative and applicable corrective actions include inspecting 
for corrosion of the wing skin panel, access door areas, and access 
doors; removing any corrosion found during the inspection; and 
replacing the access door protection plate with a new protection 
plate. Corrosion removal also includes inspecting the doubler flange 
and contacting Saab and doing repairs if the doubler flange 
thickness does not meet minimum specifications. Additional 
corrective actions include replacing conductive foil on the access 
door with an aluminum panel.

Actions and Compliance

    (f) Within 72 months after the effective date of this AD, unless 
already done, do the actions described in paragraphs (f)(1) and 
(f)(2) of this AD.
    (1) Do modification 2762 and all related investigative actions 
and applicable corrective actions, in accordance with the 
Accomplishment Instructions of Saab Service Bulletin 340-57-031, 
Revision 02, dated September 28, 2005. Do all applicable related 
investigative and corrective actions before further flight. Actions 
done before the effective date of this AD in accordance with the 
Accomplishment Instructions of Service Bulletin 340-57-031, dated 
September 4, 1996; or Revision 01, dated June 28, 1999; are 
considered acceptable for compliance with the requirements of this 
paragraph.
    (2) For airplanes identified in Saab Service Bulletin 340-57-
010, dated March 28, 1989, do the additional corrective actions 
described in and in accordance with the Accomplishment Instructions 
of that service bulletin.

FAA AD Differences

    Note 1: This AD differs from the MCAI and/or service information 
as follows: The MCAI does not require doing the actions of Saab 
Service Bulletin 340-57-010, which is specified in Saab Service 
Bulletin 340-57-031, Revision 02, as the appropriate source of 
service information for doing additional corrective actions for 
certain airplanes to completely address the unsafe condition. This 
AD requires accomplishing the additional corrective actions 
described in Service Bulletin 340-57-010 for certain airplanes.

Other FAA AD Provisions

    (g) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
International Branch, ANM-116, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. Send information to ATTN: Shahram Daneshmandi, Aerospace 
Engineer, International Branch, ANM-116, Transport Airplane 
Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 227-1112; fax (425) 227-1149. Before using any 
approved AMOC on any airplane to which the AMOC applies, notify your 
appropriate principal inspector (PI) in the FAA Flight Standards 
District Office (FSDO), or lacking a PI, your local FSDO.
    (2) Airworthy Product: For any requirement in this AD to obtain 
corrective actions from a manufacturer or other source, use these 
actions if they are FAA-approved. Corrective actions are considered 
FAA-approved if they are approved by the State of Design Authority 
(or their delegated agent). You are required to assure the product 
is airworthy before it is returned to service.
    (3) Reporting Requirements: For any reporting requirement in 
this AD, under the provisions of the Paperwork Reduction Act, the 
Office of Management and Budget (OMB) has approved the information 
collection requirements and has assigned OMB Control Number 2120-
0056.

Related Information

    (h) Refer to MCAI EASA Airworthiness Directive 2007-0168, dated 
June 15, 2007; Saab Service Bulletin 340-57-031, Revision 02, dated 
September 28, 2005; and Saab Service Bulletin 340-57-010, dated 
March 28, 1989; for related information.

    Issued in Renton, Washington, on November 30, 2007.
Stephen P. Boyd,
Assistant Manager, Transport Airplane Directorate, Aircraft 
Certification Service.
[FR Doc. E7-23870 Filed 12-7-07; 8:45 am]

BILLING CODE 4910-13-P
