[Federal Register Volume 70, Number 62 (Friday, April 1, 2005)]
[Proposed Rules]
[Pages 16767-16769]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-6448]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20785; Directorate Identifier 2005-NM-002-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 707, 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, 720, and 720B series airplanes. This proposed 
AD would require revising the Limitations section of the airplane 
flight manual (AFM). The AFM revisions include instructions for 
monitoring the low pressure lights for the center tank fuel pumps, and 
a statement prohibiting the resetting of a tripped circuit breaker for 
a fuel pump in any tank. This proposed AD is prompted by the results of 
fuel system reviews conducted by the manufacturer. We are proposing 
this AD to prevent dry operation of the fuel pumps in the center fuel 
tank, which could result in high temperatures or sparks inside the fuel 
tank, ignition of fuel vapors, and consequent fire or explosion. We are 
also issuing this AD to prohibit the resetting of a tripped circuit 
breaker for a fuel pump in any tank, which could allow an electrical 
fault to override the protective features of the circuit breaker, and 
result in sparks inside the fuel tank, ignition of fuel vapors, and 
consequent fire or explosion.

DATES: We must receive comments on this proposed AD by May 16, 2005.

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.
     By 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.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or in person at the Docket Management Facility, 
U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, 
on the plaza level of the Nassif Building, Washington, DC. This docket 
number is FAA-2005-20785; the directorate identifier for this docket is 
2005-NM-002-AD.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6501; 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 under ADDRESSES. Include ``Docket No. FAA-2005-20785; 
Directorate Identifier 2005-NM-002-AD'' in the subject line 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 submitted 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://
http://dms.dot.gov">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 website, 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

[[Page 16768]]

comment on behalf of an association, business, labor union, etc.). You 
can review DOT's complete Privacy Act Statement in the Federal Register 
published on April 11, 2000 (65 FR 19477-78), or you can visit http://
http://dms.dot.gov">dms.dot.gov.

Examining the Docket

    You can examine the AD docket on the Internet at http://
http://dms.dot.gov">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 DMS receives them.

Discussion

    The FAA has examined the underlying safety issues involved in 
recent 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'' (67 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 another 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.
    As a result of the fuel system reviews associated with SFAR 88, the 
airplane manufacturer has determined that, if the fuel pumps in the 
center fuel tank of Boeing Model 707, 720, and 720B series airplanes 
are allowed to run when the fuel quantity is low, high temperatures or 
sparks caused by metal-to-metal contact may occur, resulting in an 
ignition source for fuel vapors and consequent fire or explosion. The 
airplane manufacturer has also determined that, if a tripped circuit 
breaker for a fuel pump in any tank is reset, an ignition source may be 
created in the fuel tank. The tripping of a circuit breaker indicates 
an electrical fault, and resetting the circuit breaker may result in 
the electrical fault overriding the protective features of the circuit 
breaker, resulting in sparks inside the fuel tank, an ignition source 
for fuel vapors, and consequent fire or explosion.

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. Therefore, we are proposing this AD, which 
would require revising the Limitations section of the airplane flight 
manual. The AFM revisions include instructions for monitoring the low 
pressure lights for the center tank fuel pumps, and a statement 
prohibiting the resetting of a tripped fuel pump circuit breaker.

Costs of Compliance

    There are about 225 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
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                                                                                                                                Number of
                                                               Average                                            Cost per        U.S.-
                   Action                      Work hours    labor rate                   Parts                   airplane     registered    Fleet cost
                                                              per hour                                                          airplanes
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Revising AFM................................            1           $65   None................................          $65            90        $5,850
--------------------------------------------------------------------------------------------------------------------------------------------------------

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.

[[Page 16769]]

    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. 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 FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20785; Directorate Identifier 2005-NM-
002-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by May 16, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 707, 720, and 720B 
series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD was prompted by the results of fuel system reviews 
conducted by the manufacturer. We are issuing this AD to prevent dry 
operation of the fuel pumps in the center fuel tank, which could 
result in high temperatures or sparks inside the fuel tank, ignition 
of fuel vapors, and consequent fire or explosion. We are also 
issuing this AD to prohibit the resetting of a tripped circuit 
breaker for a fuel pump in any tank, which could allow an electrical 
fault to override the protective features of the circuit breaker, 
and result in sparks inside the fuel tank, ignition of fuel vapors, 
and consequent fire or explosion.

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 Flight Manual (AFM) Revisions

    (f) Within 30 days after the effective date of this AD: Revise 
the Limitations section of the Boeing 707 Airplane Flight Manual to 
include the following information. This may be done by inserting a 
copy of this AD into the AFM. Thereafter, operate the airplane in 
accordance with the limitations specified in these AFM revisions.
    ``OPERATION WITH BOOST PUMPS INOPERATIVE. For ground and flight 
operations, a fuel pump circuit breaker which has tripped must not 
be reset.
    CENTER TANK FUEL PUMPS. Center tank fuel pumps must not be `ON' 
unless personnel are available in the flight deck to monitor the low 
pressure lights.
    Each center tank fuel pump switch must be positioned to `OFF' 
without delay when the respective center tank fuel pump low pressure 
light illuminates.''

    Note 1: When information identical to that in paragraph (f) of 
this AD has been included in the general revision of the AFM, the 
general revision may be inserted into the AFM, and the copy of this 
AD may be removed from the AFM.

Actions Accomplished Previously

    (g) Incorporation of the information in Approval Reference 
Number 045151 of the Boeing Model 707 Airplane Flight Manual is 
considered acceptable for compliance with the corresponding action 
specified in this AD.

Alternative Methods of Compliance (AMOCs)

    (h) The Manager, Seattle Aircraft Certification Office, FAA, has 
the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.

    Issued in Renton, Washington, on March 23, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-6448 Filed 3-31-05; 8:45 am]
BILLING CODE 4910-13-P