
[Federal Register: October 31, 2008 (Volume 73, Number 212)]
[Proposed Rules]               
[Page 64892-64894]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr31oc08-22]                         

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1155; Directorate Identifier 2008-NM-146-AD]
RIN 2120-AA64

 
Airworthiness Directives; McDonnell Douglas Model 717-200 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain McDonnell Douglas Model 717-200 airplanes. This proposed AD 
would require modifying the wire installation of the auxiliary 
hydraulic pump in the right wheel well of the main landing gear (MLG). 
This proposed AD results from fuel system reviews conducted by the 
manufacturer. We are proposing this AD to prevent a tire burst when the 
MLG is in the retracted position from causing damage to the wire 
assembly of the auxiliary hydraulic pump and subsequent electrical 
arcing, creating the potential of an ignition source in the center wing 
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 December 15, 
2008.

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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this AD, contact Boeing 
Commercial

[[Page 64893]]

Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, 
California 90846, Attention: Data and Service Management, Dept. C1-L5A 
(D800-0024).

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 (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Ken Sujishi, Aerospace Engineer, Cabin 
Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (562) 627-5353; fax (562) 
627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-1155; 
Directorate Identifier 2008-NM-146-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.
    Boeing analysis determined that the existing wire installation of 
the auxiliary hydraulic pump for Model 717-200 airplanes is routed 
within the ``tire burst'' area. Replacing the components in the wire 
assembly of the auxiliary hydraulic pump with new components, and 
routing the wire assembly installation outside of the tire burst area, 
will minimize the possibility of wire damage and electrical arcing to 
the center wing fuel tank. A tire burst when the main landing gear 
(MLG) is in the retracted position might cause damage to the wire 
assembly of the auxiliary hydraulic pump and subsequent electrical 
arcing, creating the potential of an ignition source in the center wing 
tank, which, in combination with flammable fuel vapors, could result in 
a fuel tank explosion and consequent loss of the airplane.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 717-29A0009, dated 
July 31, 2008. The service bulletin describes procedures for modifying 
the wire installation of the auxiliary hydraulic pump in the right 
wheel well of the MLG. The modification includes replacing the 
components in the wire assembly of the auxiliary hydraulic pump with 
new components, and routing the wire assembly installation outside of 
the tire burst area.

FAA's Determination and Requirements of This Proposed AD

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

Costs of Compliance

    We estimate that this proposed AD would affect 8 airplanes of U.S. 
registry. We also estimate that it would take about 11 work-hours per 
product to comply with this proposed AD. The average labor rate is $80 
per work-hour. Required parts cost is minimal. Based on these figures, 
we estimate the cost of this proposed AD to the U.S. operators to be 
$7,040, or $880 per product.

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.

[[Page 64894]]

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), 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety, Incorporated 
by reference.

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 AD:

McDonnell Douglas: Docket No. FAA-2008-1155; Directorate Identifier 
2008-NM-146-AD.

Comments Due Date

    (a) We must receive comments by December 15, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to McDonnell Douglas Model 717-200 
airplanes, certificated in any category; as identified in Boeing 
Alert Service Bulletin 717-29A0009, dated July 31, 2008.

Unsafe Condition

    (d) This AD results from fuel system reviews conducted by the 
manufacturer. We are issuing this AD to prevent a tire burst when 
the main landing gear (MLG) is in the retracted position from 
causing damage to the wire assembly of the auxiliary hydraulic pump 
and subsequent electrical arcing, creating the potential of an 
ignition source in the center wing tank, which, in combination with 
flammable fuel vapors, could result in a fuel tank explosion and 
consequent loss of the airplane.

Compliance

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

Installation/Re-Routing

    (f) Within 60 months after the effective date of this AD: Modify 
the wire installation of the auxiliary hydraulic pump in the right 
wheel well of the MLG by doing all the applicable actions specified 
in the Accomplishment Instructions of Boeing Alert Service Bulletin 
717-29A0009, dated July 31, 2008.

Alternative Methods of Compliance (AMOCs)

    (g)(1) The Manager, Los Angeles Aircraft Certification Office, 
FAA, ATTN: Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical 
and Environmental Systems Branch, ANM-150L, FAA, Los Angeles 
Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, 
California 90712-4137; telephone (562) 627-5353; fax (562) 627-5210; 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19.
    (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 (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

    Issued in Renton, Washington, on October 24, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-25991 Filed 10-30-08; 8:45 am]

BILLING CODE 4910-13-P
