DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION
14 CFR Part 39
[Docket No. FAA-2008-0540; Directorate Identifier 2008-NM-031-AD] RIN
2120-AA64
AIRWORTHINESS DIRECTIVES; Bombardier Model CL-600-2C10 (Regional Jet Ser-
ies 700, 701, & 702) and Model CL-600-2D24 (Regional Jet Series 900)
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:
Bombardier Aerospace has completed a system safety review of the CL-600
-2C10/CL-600-2D24 aircraft fuel system against new fuel tank safety
standards, introduced in Chapter 525 of the Airworthiness Manual through
Notice of Proposed Amendment (NPA) 2002-043. The identified non
-compliances were assessed using Transport Canada Policy Letter No. 525
-001 to determine if mandatory corrective action is required.
This assessment showed that rupture of the fuel tank climb vent loop pipe
or leakage from pipe couplings could result in fuel coming in contact with
hot anti-ice ducts, creating potential fire on top of the centre fuel
tank.
* * * * *
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 June 12, 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 W12-140, 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: Richard Fiesel, Aerospace Engineer, Air-
frame and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification
Office, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590;
telephone (516) 228-7304; fax (516) 794-5531.
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-2008-0540; Directorate
Identifier 2008-NM-031-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
Transport Canada Civil Aviation (TCCA), which is the aviation authority
for Canada, has issued Canadian Airworthiness Directive CF-2008-01, dated
January 3, 2008 (referred to after this as "the MCAI"), to correct an
unsafe condition for the specified products. The MCAI states:
Bombardier Aerospace has completed a system safety review of the CL-600
-2C10/CL-600-2D24 aircraft fuel system against new fuel tank safety
standards, introduced in Chapter 525 of the Airworthiness Manual through
Notice of Proposed Amendment (NPA) 2002-043. The identified non
-compliances were assessed using Transport Canada Policy Letter No. 525
-001 to determine if mandatory corrective action is required.
This assessment showed that rupture of the fuel tank climb vent loop pipe
or leakage from pipe couplings could result in fuel coming in contact with
hot anti-ice ducts, creating potential fire on top of the centre fuel
tank. To correct the unsafe condition, this directive mandates the
modification of the fuel tank climb vent loop by installing shrouding
boots that direct leaked fuel safely overboard.
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.
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
Bombardier has issued Service Bulletin 670BA-28-011, Revision B, dated
July 4, 2007. 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 297 products of U.S. registry. We also estimate that it would
take about 22 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 $13,768 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 $4,611,816, or $15,528 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 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: