[Federal Register Volume 71, Number 198 (Friday, October 13, 2006)]
[Proposed Rules]
[Pages 60446-60448]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-17004]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-26048; Directorate Identifier 2006-NM-191-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 replacing certain attaching hardware of the bulkhead 
nipple assemblies of the left and right wing vent boxes with new 
electrical bonding attaching hardware, doing resistance testing of the 
new electrical bonds, and doing fuel leakage testing of the reworked 
nipple assemblies. This proposed AD results from fuel system reviews 
conducted by the manufacturer. We are proposing this AD to provide a 
conductive path, from the bulkhead nipple assemblies of the left and 
right wing vent boxes to the airframe structure inside the wing fuel 
tanks, to dissipate high amperage lightning-induced currents which 
might otherwise create an ignition source for fuel vapors inside the 
wing vent boxes and lead to an explosion of the fuel tanks.

DATES: We must receive comments on this proposed AD by November 27, 
2006.

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: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., 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 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-2006-
26048; Directorate Identifier 2006-NM-191-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 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 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

[[Page 60447]]

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.
    We have received a report indicating that a fuel system review of 
McDonnell Douglas Model 717-200 airplanes revealed that no electrical 
bonding exists between the nipple assemblies of the left and right wing 
vent boxes and the bulkhead. This condition, if not corrected, could 
result in high amperage lightning-induced currents at the bulkhead 
nipple assemblies of the left and right wing vent boxes, which might 
create an ignition source for fuel vapors inside the wing vent boxes 
and lead to an explosion of the fuel tanks.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 717-28-0011, Revision 2, 
dated July 19, 2006. The service bulletin describes procedures for 
replacing certain attaching hardware of the nipple assemblies of the 
left and right wing vent boxes with new electrical bonding attaching 
hardware; doing resistance testing of the new electrical bonds; and 
doing fuel leakage testing of the reworked nipple assemblies. 
Accomplishing the actions specified in 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, except as discussed under 
``Difference Between the Proposed AD and Service Bulletin.''

Difference Between the Proposed AD and Service Bulletin

    Boeing Service Bulletin 717-28-0011, Revision 2, recommends a 
compliance time ``not to exceed 10 years from the release date of 
Revision 1 of this service bulletin.'' However, we have determined 
that, due to the nature of the unsafe condition, 78 months after the 
effective date of this proposed AD is the appropriate compliance time. 
We have coordinated this difference with Boeing.

Costs of Compliance

    There are about 138 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 108 airplanes of 
U.S. registry. The proposed actions would take about 6 work hours per 
airplane, at an average labor rate of $80 per work hour. The 
manufacturer states that it will supply required parts to the operators 
at no cost. Based on these figures, the estimated cost of the proposed 
AD for U.S. operators is $51,840, or $480 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-2006-26048; Directorate Identifier 
2006-NM-191-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by November 
27, 2006.

[[Page 60448]]

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 717-28-0011, Revision 2, dated July 19, 2006.

Unsafe Condition

    (d) This AD results from fuel system reviews conducted by the 
manufacturer. We are issuing this AD to provide a conductive path, 
from the bulkhead nipple assemblies of the left and right wing vent 
boxes to the airframe structure inside the wing fuel tanks, to 
dissipate high amperage lightning-induced currents, which might 
otherwise create an ignition source for fuel vapors inside the wing 
vent boxes and lead to an explosion of the fuel tanks.

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.

Installing Electrical Bonding, and Resistance and Fuel Leakage Testing

    (f) Within 78 months after the effective date of this AD, 
replace certain attaching hardware of the bulkhead nipple assemblies 
of the left and right wing vent boxes with new electrical bonding 
attaching hardware, do resistance testing of the new electrical 
bonds, and do fuel leakage testing of the reworked nipple 
assemblies; in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin 717-28-0011, Revision 2, dated July 19, 
2006.

Actions Accomplished According to Previous Issue of Service Bulletin

    (g) Actions accomplished before the effective date of this AD in 
accordance with Boeing Service Bulletin 717-28-0011, Revision 1, 
dated January 24, 2006, are acceptable for compliance with the 
corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, ANM-116, International Branch, Transport 
Airplane Directorate, FAA, has, has the authority to approve AMOCs 
for this AD, if requested in accordance with the procedures found in 
14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

    Issued in Renton, Washington, on October 3, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-17004 Filed 10-12-06; 8:45 am]
BILLING CODE 4910-13-P