[Federal Register Volume 72, Number 196 (Thursday, October 11, 2007)]
[Proposed Rules]
[Pages 57894-57896]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-20051]


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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]
BILLING CODE 4910-13-P