```

[Federal Register: October 8, 2010 (Volume 75, Number 195)]
[Proposed Rules]               
[Page 62331-62333]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08oc10-7]                         

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0958; Directorate Identifier 2010-NM-188-AD]
RIN 2120-AA64

 
Airworthiness Directives; McDonnell Douglas Corporation Model DC-
9-14, DC-9-15, and DC-9-15F Airplanes; and DC-9-20, DC-9-30, DC-9-40, 
and DC-9-50 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD would require installing new 
in-line fuses for the fuel level float switch and new in-line fuses for 
the pressure switch, as applicable, and changing the wiring. The 
proposed actions would affect the left and right wing forward spars, 
center wing forward spar, forward auxiliary fuel tank, and aft 
auxiliary fuel tank, as applicable. This proposed AD was prompted by 
fuel system reviews conducted by the manufacturer. We are proposing 
this AD to prevent 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 November 22, 
2010.

ADDRESSES: You may send comments 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.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail 
dse.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may 
review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. For information on the availability of this material at the 
FAA, call 425-227-1221.

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: 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, e-mail: 
Samuel.Lee@faa.gov.

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-2010-0958; 
Directorate Identifier 2010-NM-188-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 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.
    An investigation conducted by the airplane manufacturer has 
revealed that fuel level float switch wires located on the left and 
right wing forward spars, the center tank forward spar, and the forward 
and aft auxiliary fuel tanks, and pressure switch wires located on the

[[Page 62332]]

forward and aft auxiliary fuel tanks, are routed in the same bundles as 
power wires. If a short circuit between a fuel level float or pressure 
switch wire and a power wire occurs, an over-current can cause 
excessive temperature in the fuel level float or pressure switch wire, 
resulting in damage, and could become a potential ignition source. 
Adding an in-line fuse as a self-contained component in each fuel level 
float and pressure switch circuit will minimize the possibility of 
excessive temperatures in the fuel level float or pressure switch 
wires. If a short circuit between a fuel level float or pressure switch 
and a power wire occurs, the result could be a fuel tank explosion and 
consequent loss of the airplane.

Relevant Service Information

    We reviewed Boeing Service Bulletin DC9-28-217, Revision 1, dated 
August 12, 2010. The service bulletin describes procedures for 
installing the in-line fuses of the fuel level float switch, in-line 
fuses of the pressure switch, and changing the wiring, as applicable, 
on the left and right wing forward spars, center wing forward spar, 
forward auxiliary fuel tank, and aft auxiliary fuel tank, as 
applicable. The service bulletin also describes procedures for changing 
certain wiring.

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 require accomplishing the actions specified 
in the service information described previously.

Costs of Compliance

    We estimate that this proposed AD will affect 275 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Installation....................  Up to 17 work-      Between $289 and    Between $1,734 and  Between $476,850
                                   hours x $85 per     $1,449 \1\.         $2,894 \1\.         and $795,850 \1\.
                                   hour = Up to
                                   $1,445 \1\.
----------------------------------------------------------------------------------------------------------------
\1\ Depending on airplane group identified in Boeing Service Bulletin DC9-28-217, Revision 1, dated August 12,
  2010.

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 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):

McDonnell Douglas Corporation: Docket No. FAA-2010-0958; Directorate 
Identifier 2010-NM-188-AD.

Comments Due Date

    (a) We must receive comments by November 22, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to McDonnell Douglas Corporation Model DC-9-
14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), 
DC-9-32F, DC-9-32F (C-9A), DC-9-32F (C9-B), DC-9-33F, DC-9-34, DC-9-
34F, DC-9-41, and DC-9-51 airplanes, certificated in any category; 
as identified in Boeing Service Bulletin DC9-28-217, Revision 1, 
dated August 12, 2010.

Subject

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

Unsafe Condition

    (e) This AD was prompted by fuel system reviews conducted by the 
manufacturer. We are issuing this AD to prevent 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.

Compliance

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

Installation

    (g) Within 60 months after the effective date of this AD: 
Install new in-line fuses for the fuel level float switch and new 
in-line fuses for the pressure switch, as applicable; and change the 
wiring; on the left and right wing forward spars, center wing 
forward

[[Page 62333]]

spar, forward auxiliary fuel tank, and aft auxiliary fuel tank, as 
applicable; in accordance with the Accomplishment Instructions of 
Boeing Service Bulletin DC9-28-217, Revision 1, dated August 12, 
2010.

Credit for Actions Accomplished in Accordance With Previous Service 
Information

    (h) Actions done before the effective date of this AD in 
accordance with Boeing Service Bulletin DC9-28-217, dated December 
1, 2009, are acceptable for compliance with the requirements of 
paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Los Angeles Aircraft Certification Office 
(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 Principal 
Maintenance Inspector or Principal Avionics Inspector, as 
appropriate, or lacking a principal inspector, your local Flight 
Standards District Office.

Related Information

    (j) For more information about this AD, contact Samuel Lee, 
Aerospace Engineer, Propulsion Branch, ANM-140L, FAA, Los Angeles 
ACO, 3960 Paramount Boulevard, Lakewood, California 90712-4137; 
phone: (562) 627-5262; fax: (562) 627-5210; e-mail: 
Samuel.Lee@faa.gov.
    (k) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-
0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail 
dse.boecom@boeing.com; Internet https://www.myboeingfleet.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, the FAA, 1601 Lind Avenue, SW., 
Renton, Washington. For information on the availability of this 
material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on October 1, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-25374 Filed 10-7-10; 8:45 am]
BILLING CODE 4910-13-P
```