[Federal Register: October 11, 2007 (Volume 72, Number 196)]
[Proposed Rules]
[Page 57894-57896]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11oc07-21]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-29330; Directorate Identifier 2007-NM-199-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model 717-200
Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain McDonnell Douglas Model 717-200 airplanes. This proposed AD
would require electrical bonding of the fill valves for the right and
left main fuel tanks, the fill valve and pipe assembly
[[Page 57895]]
for the center wing fuel tank, and the defuel shutoff valve. This
proposed AD results from a fuel system review conducted by the
manufacturer. We are proposing this AD to prevent improper bonding of
the fill valves and defuel shutoff valve for the main fuel tanks and
center wing tank, which, in combination with a lightning strike, could
result in a fuel tank explosion and consequent loss of the airplane.
DATES: We must receive comments on this proposed AD by November 26,
2007.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed AD.
DOT Docket Web site: Go to http://dms.dot.gov and follow
the instructions for sending your comments electronically.
Government-wide rulemaking Web site: Go to http://www.regulations.gov
and follow the instructions for sending your
comments electronically.
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.
Fax: (202) 493-2251.
Hand Delivery: Room W12-140 on the ground floor of the
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
Contact Boeing Commercial Airplanes, Long Beach Division, 3855
Lakewood Boulevard, Long Beach, California 90846, Attention: Data and
Service Management, Dept. C1-L5A (D800-0024), for the service
information identified in this proposed AD.
FOR FURTHER INFORMATION CONTACT: Samuel S. Lee, Aerospace Engineer,
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137;
telephone (562) 627-5262; fax (562) 627-5210.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to submit any relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed in the ADDRESSES section. Include the docket number ``FAA-2007-
29330; Directorate Identifier 2007-NM-199-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments received by the closing date and may amend the
proposed AD in light of those comments.
We will post all comments we receive, without change, to http://dms.dot.gov
, including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA
personnel concerning this proposed AD. Using the search function of
that Web site, anyone can find and read the comments in any of our
dockets, including the name of the individual who sent the comment (or
signed the comment on behalf of an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov
, or in person at the Docket Operations office between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The
Docket Operations office (telephone (800) 647-5527) is located on the
ground level of the West Building at the DOT street address stated in
the ADDRESSES section. Comments will be available in the AD docket
shortly after the Docket Management System receives them.
Discussion
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 intend 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 proposed 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.
We have received a report indicating that, during fuel tank design
review of Model 717-200 airplanes, Boeing found that the fill valves
and defuel shutoff valve of the right wing leading edge fuel tank were
not electrically bonded to the attaching structure mounting flanges.
Investigation revealed that the electrical bonding design requirement
was inadvertently omitted during production. Although no reports or
incidents have resulted from this condition, electrical bonds should be
installed to ensure that lightning-induced high amperage current levels
have the correct flow path to the wing fuel tank structure. Improper
bonding of the fill valves and defuel shutoff valve for the main fuel
tanks and center wing tank, if not corrected, in combination with a
lightning strike, could result in a fuel tank explosion and consequent
loss of the airplane.
Relevant Service Information
We have reviewed Boeing Service Bulletin 717-28-0012, Revision 1,
dated June 7, 2006. The service bulletin describes procedures for
electrical bonding of the fill valves for the right and left main fuel
tanks, the fill valve and pipe assembly for the center wing fuel tank,
and the defuel shutoff valve. Accomplishing the actions specified in
[[Page 57896]]
the service information is intended to adequately address the unsafe
condition.
FAA's Determination and Requirements of the Proposed AD
We have evaluated all pertinent information and identified an
unsafe condition that is likely to exist or develop on other airplanes
of this same type design. For this reason, we are proposing this AD,
which would require accomplishing the actions specified in the service
information described previously.
Costs of Compliance
There are about 134 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 104 airplanes of
U.S. registry. The proposed actions would take about 4 work hours per
airplane, at an average labor rate of $80 per work hour. Required parts
would cost about $9 per airplane. Based on these figures, the estimated
cost of the proposed AD for U.S. operators is $34,216, or $329 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 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 that the 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. 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, 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 Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
McDonnell Douglas: Docket No. FAA-2007-29330; Directorate Identifier
2007-NM-199-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by November
26, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to McDonnell Douglas Model 717-200
airplanes, certificated in any category, as identified in Boeing
Service Bulletin 717-28-0012, Revision 1, dated June 7, 2006.
Unsafe Condition
(d) This AD results from a fuel system review conducted by the
manufacturer. We are issuing this AD to prevent improper bonding of
the fill valves and defuel shutoff valve for the main fuel tanks and
center wing tank, which, in combination with a lightning strike,
could result in a fuel tank explosion and consequent loss of the
airplane.
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.
Electrical Bonding
(f) Within 60 months after the effective date of this AD,
accomplish the electrical bonding of the fill valves for the right
and left main fuel tanks, the fill valve and pipe assembly for the
center wing fuel tank, and the defuel shutoff valve, in accordance
with the Accomplishment Instructions of Boeing Service Bulletin 717-
28-0012, Revision 1, dated June 7, 2006.
Credit for Actions Done Using the Previous Service Information
(g) Actions accomplished before the effective date of this AD in
accordance with Boeing Service Bulletin 717-28-0012, dated April 16,
2004, are considered acceptable for compliance with the
corresponding actions specified in paragraph (f) of this AD.
Alternative Methods of Compliance (AMOCs)
(h)(1) The Manager, Los Angeles Aircraft Certification Office
(ACO), FAA, has the authority to approve AMOCs for this AD, if
requested in accordance with the procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
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.
Issued in Renton, Washington, on October 1, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-20051 Filed 10-10-07; 8:45 am]
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