[Federal Register: August 1, 2007 (Volume 72, Number 147)]
[Proposed Rules]
[Page 41958-41963]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01au07-26]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-28828; Directorate Identifier 2007-NM-010-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 707 Airplanes and Model
720 and 720B Series 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 all Boeing Model 707 airplanes and Model 720 and 720B series
airplanes. This proposed AD would require accomplishing an airplane
survey to define the configuration of certain system installations, and
repair of any discrepancy found. This proposed AD would also require
modifying the fuel system by installing lightning protection for the
fuel quantity indication system (FQIS), ground fault relays for the
fuel boost pumps, and additional power relays for the center tank fuel
pumps and uncommanded on-indication lights at the flight engineer's
panel. This proposed AD results from fuel system reviews conducted by
the manufacturer. We are proposing this AD to prevent certain failures
of the fuel pumps or FQIS, which could result in a potential ignition
source inside the fuel tank, which, in combination with flammable fuel
vapors, could result in a fuel tank explosion and consequent loss of
the airplane.
DATES: We must receive comments on this proposed AD by September 17,
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, P.O. Box 3707, Seattle,
Washington 98124-2207, for the service information identified in this
proposed AD.
FOR FURTHER INFORMATION CONTACT: Kathrine Rask, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6505; fax (425) 917-6590.
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-
28828; Directorate Identifier 2007-NM-010-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 floor of the West Building at the 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 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),
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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.
Results from the SFAR 88 analysis show that potential ignition
sources include:
Fuel pump electrical failures that burn through the pump
end cap or case.
Fuel pump electrical failures that burn through the wire
and cause electrical arcing through the conduit.
Mechanical failure of center tank fuel pumps due to
uncommanded operation that causes an ignition source and an arc in a
wing tank due to a latent in-tank degradation of the fuel quantity
indication system (FQIS) and a lightning strike.
We have determined that the actions identified in this AD are
necessary to prevent certain failures of the fuel pumps or FQIS, which
could result in a potential ignition source inside the fuel tank,
which, in combination with flammable fuel vapors, could result in fuel
tank explosion and consequent loss of the airplane.
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 modifying the fuel system by installing lightning
protection for the fuel quantity indication system (FQIS), ground fault
relays for the fuel boost pumps, and additional power relays for the
center tank fuel pumps and uncommanded on-indication lights at the
flight engineer's panel.
To date, the airframe manufacturer has not developed service
information for the modifications proposed by this AD. Due to the age
of the subject airplane models, the operator needs to conduct an
airplane survey to define the configuration of system installations for
the wing leading edges, wing-to-body area, electrical equipment bay,
flight deck, and FQIS to facilitate development of the required service
information. The survey would identify locations where new components
and wire bundles could be installed, as well as the configuration of
affected systems.
Therefore, to ensure that service information is available within a
reasonable time to allow modification of the airplane; this proposed AD
would also require conducting an airplane survey, and reporting the
results to the FAA. The report would include photographs and sketches,
part numbers of certain components, and the actual configuration of
certain systems.
Due to the age of these airplanes, it is possible that
discrepancies (i.e., wear or deterioration) might be detected during
the survey. This proposed AD would also require repair of those
discrepancies.
Ensuring Compliance with Airplane Survey
Appendix 1 of this proposed AD contains the 707 SFAR 88 survey
areas. The appendix is for informational use and provides highlights of
the general content of the required survey to assist operators in
developing an acceptable survey plan. Operators may wish to use the
appendix as an aid to implement the airplane survey.
Costs of Compliance
There are about 185 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 52 airplanes of
U.S. registry.
The proposed survey would take about 20 work hours per airplane, at
an average labor rate of $80 per work hour. Based on these figures, the
estimated cost of the proposed survey for U.S. operators is $83,200, or
$1,600 per airplane.
Because the manufacturer has not yet developed a modification
commensurate with the actions specified by this proposed AD, we cannot
provide specific information regarding the required number of work
hours or the cost of parts to do the proposed modification. In
addition, modification costs will likely vary depending on the operator
and the airplane configuration. The proposed compliance time of 72
months should provide ample time for the development, approval, and
installation of an appropriate modification.
Based on similar modifications accomplished previously on other
airplane models, however, we can reasonably estimate that the proposed
modification may require as many as 420 work hours per airplane, at an
average labor rate of $80 per work hour. Required parts may cost up to
$185,000 per airplane. Based on these figures, the estimated cost of
the proposed modification for U.S. operators is $11,367,200, or
$218,600 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):
[[Page 41960]]
Boeing: Docket No. FAA-2007-28828; Directorate Identifier 2007-NM-
010-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by September
17, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to all Boeing Model 707-100 long body, -200,
-100B long body, and -100B short body series airplanes; and Model
707-300, -300B, -300C, and -400 series airplanes; and Model 720 and
720B series airplanes; certificated in any category.
Unsafe Condition
(d) This AD results from fuel system reviews conducted by the
manufacturer. We are issuing this AD to prevent certain failures of
the fuel pumps or fuel quantity indication system (FQIS), which
could result in a potential ignition source inside the fuel tank,
which, in combination with flammable fuel vapors, could result in
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.
Airplane Survey
(f) Within 12 months after the effective date of this AD:
Conduct an airplane survey that defines the configuration of system
installations for the wing leading edges, wing-to-body area,
electrical equipment bay, flight deck, and FQIS using a method
approved in accordance with the procedures specified in paragraph
(h)(1) of this AD. If any discrepancy is detected, repair before
further flight using a method approved in accordance with the
procedures specified in paragraph (h)(1) of this AD. Submit the
survey results to the Manager, Seattle Aircraft Certification Office
(ACO), FAA, 1601 Lind Avenue SW., Renton, Washington 98057-3356, at
the applicable time specified in paragraph (f)(1) or (f)(2) of this
AD. The report must include the survey results (e.g., photographs
and sketches, part numbers of FQIS components and fuel pumps, and
the actual configuration of FQIS and the fuel pump control systems),
a description of any discrepancy found, the airplane serial number,
and the number of landings and flight hours on the airplane. Under
the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et
seq.), the Office of Management and Budget (OMB) has approved the
information collection requirements contained in this AD and has
assigned OMB Control Number 2120-0056.
(1) If the survey was done after the effective date of this AD:
Submit the report within 30 days after the survey.
(2) If the survey was done before the effective date of this AD:
Submit the report within 30 days after the effective date of this
AD.
Note 1: For the purposes of this AD, ``discrepancy'' is defined
as any wear or deterioration (e.g., damage, fluid leaks, corrosion,
cracking, or system failures) that might prevent the airplane from
being in an airworthy condition.
Modification of Fuel System
(g) Within 72 months after the effective date of this AD: Modify
the fuel system as specified in paragraphs (g)(1), (g)(2), and
(g)(3) of this AD, using a method approved in accordance with the
procedures specified in paragraph (h)(1) of this AD.
(1) Replace the FQIS wire bundle along the leading edge of the
left and right wings with a new wire bundle that has a lightning
shield that is separated from other wiring.
(2) Replace each fuel pump relay with a ground fault interrupter
relay.
(3) Install redundant power relays for the center tank fuel
pumps and uncommanded on-indication lights at the flight engineer's
panel.
Alternative Methods of Compliance (AMOCs)
(h)(1) The Manager, Seattle ACO has the authority to approve
AMOCs for this AD, if requested in accordance with the procedures
found in 14 CFR 39.19.
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(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
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(PI) in the FAA Flight Standards District Office (FSDO), or lacking
a PI, your local FSDO.
Issued in Renton, Washington, on July 18, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 07-3712 Filed 7-31-07; 8:45 am]
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