
[Federal Register Volume 77, Number 173 (Thursday, September 6, 2012)]
[Rules and Regulations]
[Pages 54793-54796]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-21838]


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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; 
Amendment 39-17181; AD 2012-18-05]
RIN 2120-AA64


Airworthiness Directives; the Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting 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; equipped 
with center wing fuel tank and Boeing original equipment manufacturer-
installed auxiliary fuel tanks. This AD was prompted by fuel system 
reviews conducted by the manufacturer. This AD requires adding design 
features to detect electrical faults and to detect a pump running in an 
empty fuel tank. 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.

DATES: This AD is effective October 11, 2012.

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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Serj Harutunian, Aerospace Engineer, 
Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
phone: 562-627-5254; fax: 562-627-5210; email: serj.harutunian@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM published in the Federal Register on November 14, 2011 (76 FR 
70377). That NPRM proposed to 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.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 70377, November 14, 2011) and the FAA's response to each 
comment.

Request To Revise Applicability

    Boeing requested that we revise the applicability of the NPRM (76 
FR 70377, November 14, 2011) to exclude airplanes from which auxiliary 
fuel tanks have been removed, and to add certain airplanes equipped 
with a center wing fuel tank. Boeing stated that the system safety 
assessments (SSAs) of Special Federal Aviation Regulation No. 88 
(``SFAR 88,'' Amendment 21-78 (66 FR 23086, May 7, 2001) concluded that 
design changes were required on all auxiliary fuel tanks on Model DC-9, 
MD-80, and MD-90 airplanes, and on the center wing fuel tank on Model 
MD-80 and MD-90 airplanes. American Airlines (American) concurred with 
Boeing's position on this issue.
    We agree to limit the applicability of this AD to affected 
airplanes equipped with center wing fuel tanks and Boeing OEM-installed 
auxiliary fuel tanks. We also agree that airplanes on which auxiliary 
fuel tanks have been removed are not subject to the requirements of 
this AD. We have revised paragraph (c) in this final rule accordingly.

Requests To Remove Criteria for Mean Time Between Failures (MTBF)

    Boeing and TDG Aerospace requested that we provide justification 
for the removal of pump nuisance trip relative to the 100,000-hour MTBF 
reliability requirements to mitigate the ignition prevention unsafe 
condition. The commenters asserted that the 100,000-hour MTBF 
reliability requirement is not a contributing factor to the ignition 
source unsafe condition for design changes mandated by the NPRM (76 FR 
70377, November 14, 2011). American concurred with Boeing's position on 
this issue.
    We agree with the request. The MTBF of the component will be 
addressed in the design change package provided for certification to 
satisfy the criteria for compliance with the requirements of this AD. 
We have accordingly removed paragraph (g)(3) in this final rule.

Request To Redefine Certain Failure Conditions

    Boeing claimed that the NPRM (76 FR 70377, November 14, 2011) was 
too broad in its descriptions of the unsafe failure modes. Boeing 
requested that we revise paragraph (g) of the NPRM to define the 
failure modes that would require corrective action as electrical faults 
that are ``capable of burning through the pump housing's explosion-
proof boundaries'' (instead of those that ``can cause arcing and burn 
through the fuel pump housing,'' as specified in the NPRM). Boeing 
asserted that this clarification would ensure that the corrective 
actions would target only the potential fuel tank ignition sources 
identified during the SSAs, by identifying only those fuel pump 
electrical faults and fuel pump dry-running conditions capable of 
developing a fuel tank ignition source. American concurred with 
Boeing's position on this issue.
    We disagree with the request. Narrowing the failure conditions to 
certain types of failures or certain explosion-proof pump boundaries 
would limit the application of a broader

[[Page 54794]]

array of ignition prevention solutions. We have not changed the final 
rule regarding this issue.

Request To Remove Certain Restriction

    Paragraph (g)(2) of the NPRM (76 FR 70377, November 14, 2011) 
specified that the new pump shutoff system must shut off each pump no 
later than 60 seconds after the fuel tank is emptied. Noting that the 
SFAR 88 SSAs recommended minimizing dry-running time but provided no 
specific dry-running time limit, Boeing requested that we remove the 
60-second restriction. Boeing suggested basing dry-running time limits 
on the risk of developing a fuel tank ignition source threat by the 
affected designs, and added that the pump shutoff design feature must 
balance that risk against adding to crew workload to correct nuisance 
pump shutoffs in a near-empty fuel tank. Boeing noted that the FAA has 
approved auto-shutoff timers on other airplane designs that may allow 
pumps to run longer than 60 seconds after a fuel tank was emptied. 
American concurred with Boeing's position on this issue.
    We do not agree to remove the 60-second pump shutoff restriction. 
The intent of this AD is to mandate that fuel pumps be shut off after 
fuel tanks empty to prevent pump dry running. The FAA has mandated a 
15-second shutoff time on other applications, and has determined that a 
60-second shutoff time is not unreasonable in this case. We have not 
changed the final rule regarding this issue.

Request To Mandate Airworthiness Limitations

    Boeing noted that the NPRM (76 FR 70377, November 14, 2011) would 
not mandate airworthiness limitations such as critical design 
configuration control limitations (CDCCLs) and/or repetitive 
inspections or functional checks for the proposed changes. Boeing 
requested that we revise Note 1 of the NPRM to require operators to 
comply with any related airworthiness limitations. American concurred 
with Boeing's position on this issue.
    We disagree with the request to mandate airworthiness limitations. 
CDCCLs for this design are not defined yet and will be included in the 
certification approval, as required under paragraph (g) of this AD. We 
have removed Note 1 in this final rule, but have otherwise not changed 
the AD regarding this issue.

Request To Delay Issuance of Final Rule

    American requested that we delay issuing the final rule pending the 
release of service information associated with the design features 
proposed by the NPRM (76 FR 70377, November 14, 2011). American 
indicated that additional time is necessary to allow operators time for 
reviewing the modification options, planning, ordering modification 
parts, and completing the required work during a heavy maintenance 
check.
    We disagree with the request. Delaying issuance of this AD would 
have adverse safety implications. We anticipate that FAA-approved 
design solutions will be available in sufficient time for operators to 
comply with the AD within 60 months. We have not changed the final rule 
regarding this issue.

Request To Clarify Terminology

    TDG Aerospace requested that we clarify the term ``preclude'' as 
used in the NPRM (76 FR 70377, November 14, 2011) in paragraph (g)(2): 
``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.'' TDG Aerospace considered ``undetected running of a 
fuel pump'' a significant latent failure condition, as defined by FAA 
Advisory Circular 25.981-1C, ``Fuel Tank Ignition Source Prevention 
Guidelines,'' dated September 19, 2008 (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2025_981-1.pdf). TDG 
therefore requested that we confirm that use of the word ``preclude'' 
is done in the context of the allowable period of latency for 
significant latent failure conditions (i.e., one flight cycle). The 
commenter did not justify or further explain the request.
    We agree that the word ``preclude'' is consistent with failure 
latency period equal to one flight accommodated in paragraph 10.c.(3) 
of FAA AC 25.981-1C. We have not changed the final rule regarding this 
issue.

Request To Approve Modification

    American requested that we approve for compliance with the NPRM (76 
FR 70377, November 14, 2011) the installation of a certain universal 
fault interrupter that American alleges will adequately address the 
unsafe condition. American stated that the functionality of this 
modification has been demonstrated and approved as equivalent or 
exceeding the protection provided by that of a standard ground fault 
interrupter (GFI) relay previously approved for AD 2011-18-03, 
Amendment 39-16785 (76 FR 53317, August 26, 2011); and AD 2011-20-07, 
Amendment 39-16818 (76 FR 60710, September 30, 2011).
    We disagree with the request. Those parts have not been approved 
for these airplanes. The referenced ADs apply to airplanes not affected 
by this AD, and do not address the same unsafe condition identified in 
this AD. We have not changed the final rule regarding this issue.

Request To Add Flight Crew Notification

    The Air Line Pilots Association, International (ALPA) fully 
supported the proposed requirements of the NPRM (76 FR 70377, November 
14, 2011), and requested an additional design feature that would notify 
the flight crew when the fuel pump has been automatically shut off if 
an electrical anomaly is detected or if the fuel tank is empty.
    We disagree with the request. When the fuel pump is automatically 
shut off because of an electrical anomaly, the flight crew will be 
unable to take any further action to start up the pump, so 
notifications of this condition to the flight crew would serve no 
purpose. Electrical failures that automatically shut off the pump are 
logged for maintenance action after landing to safely restart the pump. 
We have not changed the final rule regarding this issue.

Request To Revise Cost Estimate

    Boeing requested that we revise the cost estimates specified in the 
NPRM (76 FR 70377, November 14, 2011) to reflect updated fleet size 
information. American concurred with this request.
    We have reviewed the fleet information provided by Boeing, and have 
revised the estimated costs accordingly in this final rule.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM (76 FR 70377, November 14, 2011) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 70377, November 14, 2011).
    We also determined that these changes will not increase the 
economic

[[Page 54795]]

burden on any operator or increase the scope of the AD.

Costs of Compliance

    We estimate that this AD affects 809 airplanes of U.S. registry. We 
estimate the following costs to comply with this AD:

                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Installing design features--for         50 work-hours x $85 per          $35,000         $39,250     $10,322,750
 airplanes with center wing and          hour = $4,250.
 auxiliary tanks (263 airplanes).
Installing design features--for         35 work-hours x $85 per           17,000          19,975      10,906,350
 airplanes with center wing tank (546    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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2012-18-05 The Boeing Company: Amendment 39-17181; Docket No. FAA-
2011-1229; Directorate Identifier 2011-NM-132-AD.

(a) Effective Date

    This AD is effective October 11, 2012.

(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 center wing fuel tanks and Boeing 
original equipment manufacturer-installed auxiliary fuel tanks. For 
airplanes from which the auxiliary fuel tanks have been removed, the 
actions specified in this AD are not required.
    (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) and 
(g)(2) 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.

(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

[[Page 54796]]

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: 
serj.harutunian@faa.gov.

(j) Material Incorporated by Reference

    None.

    Issued in Renton, Washington, on August 6, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-21838 Filed 9-5-12; 8:45 am]
BILLING CODE 4910-13-P


