[Federal Register Volume 76, Number 219 (Monday, November 14, 2011)]
[Proposed Rules]
[Pages 70377-70379]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-29303]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1229; Directorate Identifier 2011-NM-132-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain The Boeing Company Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, 
and DC-9-50 series airplanes; and Model DC-9-81 (MD-81), DC-9-82 (MD-
82), DC-9-83 (MD-83), DC-9-87 (MD-87), MD-88, and MD-90-30 airplanes, 
that are equipped with auxiliary fuel tanks. This proposed AD was 
prompted by fuel system reviews conducted by the manufacturer. This 
proposed AD would require adding design features to detect electrical 
faults, to detect a pump running in an empty fuel tank, and to ensure 
that a fuel pump's operation is not affected by certain conditions. We 
are proposing this AD 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.

DATES: We must receive comments on this proposed AD by December 29, 
2011.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     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.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: (800) 647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Serj Harutunian, Aerospace Engineer, 
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712-
4137; phone: (562) 627-5254; fax: (562) 627-5210; email: 
[email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-1229; 
Directorate Identifier 2011-NM-132-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

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

[[Page 70378]]

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 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.
    A fuel pump may cause an ignition source in a fuel tank when it has 
internal electrical faults, or when the pump overheats due to prolonged 
dry running in an empty fuel tank. Electrical faults inside fuel pumps 
may cause arcing and burn through the pump housing. Electrical arcs 
entering an empty fuel tank may cause the fuel vapors to ignite. If a 
pump is not shut off in a timely manner when the tank is emptied, the 
dry-running pump may cause excessive heat and become an ignition source 
inside the tank.

FAA's Findings

    During the SFAR 88 safety assessment, it was determined that each 
electrically powered fuel pump installed in the center wing tank and/or 
auxiliary fuel tank must have a protective device installed to detect 
electrical faults, which can cause arcing and burn-through of the fuel 
pump housing. That same device must shut off the pump by automatically 
removing electrical power from the pump when such faults are detected. 
It was also determined that design features must be added to detect 
when a center wing tank or auxiliary tank is emptied such that each 
pump is manually or automatically shut off within 60 seconds after it 
is emptied. The design features must also preclude undetected running 
of a fuel pump in an empty tank, after the pump was commanded off 
manually or automatically. The design features must also ensure that a 
fuel pump cannot be shut off due to system failures sooner than a 
specified length of time.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would prohibit operation of an affected airplane 
as of 60 months after the effective date of the AD, unless an amended 
type certificate or supplemental type certificate that incorporates the 
following design features and requirements has been approved by the 
FAA, and those design features are installed on the airplane.
     A protective device for each electrically powered fuel 
pump that will detect electrical faults and shut off the pump 
automatically when such faults are detected
     Additional design features to detect any center wing tank 
or auxiliary fuel tank pump running in an empty fuel tank and to shut 
off each pump within a specified time
     Means to ensure that a fuel pump cannot be shut off due to 
system failures sooner than a specified length of time.
    This proposed AD would also prohibit operation of any airplane 
affected by this AD unless the FAA-approved design features specified 
in the certification plans are installed within a specified time.

Costs of Compliance

    We estimate that this proposed AD affects 1,288 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
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Installing design features--for         50 work-hours x $85 per          $35,000         $39,250     $23,550,000
 airplanes with center wing and          hour = $4,250.
 auxiliary tanks (600 airplanes).
Installing design features--for         35 work-hours x $85 per           17,000          19,975      13,742,800
 airplanes with center wing tank (688    hour = $2,975.
 airplanes).
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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 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 this 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

[[Page 70379]]

Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
Reference, 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):

The Boeing Company: Docket No. FAA-2011-1229; Directorate Identifier 
2011-NM-132-AD.

(a) Comments Due Date

    We must receive comments by December 29, 2011.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company airplanes, certificated in 
any category, as identified in paragraphs (c)(1) through (c)(8) of 
this AD, and equipped with auxiliary fuel tanks.
    (1) Model DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, and DC-9-
15F airplanes.
    (2) Model DC-9-21 airplanes.
    (3) Model DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, 
DC-9-34, DC-9-34F, and DC-9-32F (C-9A, C-9B) airplanes.
    (4) Model DC-9-41 airplanes.
    (5) Model DC-9-51 airplanes.
    (6) Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and 
DC-9-87 (MD-87) airplanes.
    (7) Model MD-88 airplanes.
    (8) Model MD-90-30 airplanes.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 28: Fuel.

(e) Unsafe Condition

    This AD was prompted by fuel system reviews conducted by the 
manufacturer. We are issuing this AD 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.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Criteria for Operation

    As of 60 months after the effective date of this AD, no person 
may operate any airplane affected by this AD unless an amended type 
certificate or supplemental type certificate that incorporates the 
design features and requirements described in paragraphs (g)(1), 
(g)(2), and (g)(3) of this AD has been approved by the Manager, Los 
Angeles Aircraft Certification Office (ACO), FAA, and those design 
features are installed on the airplane.
    (1) Each electrically powered fuel pump installed in the center 
wing tank or auxiliary fuel tank must have a protective device 
installed to detect electrical faults that can cause arcing and burn 
through the fuel pump housing. The same device must shut off the 
pump by automatically removing electrical power from the pump when 
such faults are detected. When a fuel pump is shut off as the result 
of detection of an electrical fault, the device must stay latched 
off until the fault is cleared through maintenance action and 
verified that the pump and the electrical power feed is safe for 
operation.
    (2) Additional design features must be installed to detect when 
any center wing tank or auxiliary fuel tank pump is running in an 
empty fuel tank. The prospective pump shutoff system must shut off 
each pump no later than 60 seconds after the fuel tank is emptied. 
The pump shutoff system design must preclude undetected running of a 
fuel pump in an empty tank, after the pump was commanded off 
manually or automatically.
    (3) The implementation of the design features defined in 
paragraphs (g)(1) and (g)(2) of this AD must ensure that a fuel pump 
cannot be shut off due to system failures including nuisance 
shutoffs sooner than 100,000 hours' mean time between failures 
(MTBF).
    Note 1: After accomplishing the installation specified in 
paragraph (g) of this AD, maintenance and/or preventative 
maintenance under 14 CFR part 43 is permitted provided the 
maintenance does not result in changing the AD-mandated 
configuration (reference 14 CFR 39.7).

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the ACO, send it to the attention of the person 
identified in the Related Information section of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(i) Related Information

    For more information about this AD, contact Serj Harutunian, 
Aerospace Engineer, Propulsion Branch, ANM-140L, FAA, Los Angeles 
ACO, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
phone: (562) 627-5254; fax: (562) 627-5210; email: 
[email protected].

    Issued in Renton, Washington, on October 28, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-29303 Filed 11-10-11; 8:45 am]
BILLING CODE 4910-13-P