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[Federal Register: May 19, 2010 (Volume 75, Number 96)]
[Proposed Rules]               
[Page 27966-27969]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19my10-16]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0480; Directorate Identifier 2010-NM-035-AD]
RIN 2120-AA64

 
Airworthiness Directives; The Boeing Company Model 747-400 and 
747-400D Series 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 Model 747-400 and 747-400D series airplanes. This proposed AD 
would

[[Page 27967]]

require installing aluminum gutter reinforcing brackets to the forward 
and aft drip shield gutters of the main equipment center (MEC); and 
adding a reinforcing fiberglass overcoat to the top surface of the MEC 
drip shield, including an inspection for cracking and holes in the MEC 
drip shield, and corrective actions if necessary. This proposed AD also 
provides for an option to install an MEC drip shield drain system, 
which, if accomplished, would extend the compliance time for adding the 
reinforcing fiberglass overcoat to the top surface of the MEC drip 
shield. This proposed AD results from a report indicating that an 
operator experienced a multi-power system loss in-flight of 1, 
2, and 3 alternating current (AC) electrical power 
systems located in the MEC. We are proposing this AD to prevent water 
penetration into the MEC, which could result in the loss of flight 
critical systems.

DATES: We must receive comments on this proposed AD by July 6, 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: 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 proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.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 (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Marcia Smith, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6484; fax (425) 917-6590.

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-2010-0480; 
Directorate Identifier 2010-NM-035-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

    We received a report indicating that an operator experienced a 
multi-power system loss in-flight of 1, 2, and 
3 AC electrical power systems located in the main equipment 
center (MEC). The forward MEC drip shield gutters and exhaust plenum 
have each been identified as part of the leak path into the MEC. 
Multiple operators have reported MEC drip shield gutter and upper 
surface cracks. These cracks can allow water to penetrate the MEC drip 
shield and enter the MEC. This condition, if not corrected, could allow 
water penetration into the MEC, which could result in the loss of 
flight critical systems.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-25A3555, dated 
November 4, 2009. The service bulletin describes procedures for 
installing aluminum gutter reinforcing brackets to the forward and aft 
drip shield gutters of the main equipment center (MEC). The service 
bulletin also describes procedures for adding a reinforcing fiberglass 
overcoat to the top surface of the MEC drip shield, including a general 
visual inspection for cracking and holes in the top surface of the MEC 
drip shield, and corrective actions if necessary. The corrective 
actions include repairing any crack or hole found. The service bulletin 
also describes procedures for an option to install an MEC drip shield 
drain system, which, if accomplished, would extend the compliance time 
for adding the reinforcing fiberglass overcoat.

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 71 airplanes of U.S. 
registry. The following table provides the estimated costs, depending 
on airplane configuration, for U.S. operators to comply with this 
proposed AD.

                                                                 Table--Estimated Costs
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                                                                                                                       Number of
                                                             Average                                                     U.S.-
              Action                      Work hours        labor rate          Parts             Cost per product     registered        Fleet cost
                                                             per hour                                                  airplanes
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Install Brackets..................  Between 7 and 8 \1\..          $85  None.................  Up to $680 \1\.......           71  Up to $48,280.\1\
Add Overcoat......................  Between 11 and 12 \1\           85  None.................  Up to $1,020 \1\.....           71  Up to $72,420.\1\

[[Page 27968]]

Install Optional MEC Drip Shield    Between 12 and 13 \1\           85  Up to $8,982 \1\.....  Up to $10,087 \1\....           71  Up to $716,177.\1\
 Drain System.
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\1\ Depending on work package.

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), 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, 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 AD:

The Boeing Company: Docket No. FAA-2010-0480; Directorate Identifier 
2010-NM-035-AD.

Comments Due Date

    (a) We must receive comments by July 6, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 747-400 and 747-
400D series airplanes, certificated in any category; as identified 
in Boeing Alert Service Bulletin 747-25A3555, dated November 4, 
2009.

Subject

    (d) Air Transport Association (ATA) of America Code 25: 
Equipment/Furnishings.

Unsafe Condition

    (e) This AD results from a report indicating that an operator 
experienced a multi-power system loss in-flight of 1, 
2, and 3 alternating current electrical power 
systems located in the main equipment center (MEC). The Federal 
Aviation Administration is issuing this AD to prevent water 
penetration into the MEC, which could result in loss of flight 
critical systems.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Modification

    (g) Do the actions specified in either paragraph (g)(1) or 
(g)(2) of this AD, at the times specified in those paragraphs, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-25A3555, dated November 4, 2009 (``the service 
bulletin'').
    (1) Within 24 months after the effective date of this AD, 
install the reinforcing brackets of the MEC drip shield aluminum 
gutter, in accordance with Work Package 1 of the Accomplishment 
Instructions of the service bulletin; and add a reinforcing 
fiberglass overcoat to the top surface of the MEC drip shield, 
including doing a general visual inspection for cracking and holes 
in the top surface of the MEC drip shield, and doing all applicable 
corrective actions, in accordance with Work Package 3 of the 
Accomplishment Instructions of the service bulletin. Do all 
applicable corrective actions before further flight after doing the 
general visual inspection.
    (2) Do the actions specified in paragraphs (g)(2)(i) and 
(g)(2)(ii) of this AD.
    (i) Within 24 months after the effective date of this AD, 
install the reinforcing brackets of the MEC drip shield aluminum 
gutter, in accordance with Work Package 1 of the Accomplishment 
Instructions of the service bulletin; and install a MEC drip shield 
drain system, in accordance with Work Package 2 of the 
Accomplishment Instructions of the service bulletin.
    (ii) Within 96 months after the effective date of this AD, add a 
reinforcing fiberglass overcoat to the top surface of the MEC drip 
shield, including doing a general visual inspection for cracking and 
holes in the top surface of the MEC drip shield, and doing all 
applicable corrective actions, in accordance with Work Package 3 of 
the Accomplishment Instructions of the service bulletin. Do all 
applicable corrective actions before further flight after doing the 
general visual inspection.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle 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. Send information to 
ATTN: Marcia Smith, Aerospace Engineer, Cabin Safety and 
Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 
98057-3356; telephone (425) 917-6484; fax (425) 917-6590. 
Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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 principal maintenance inspector

[[Page 27969]]

(PMI) or principal avionics inspector (PAI), as appropriate, or 
lacking a principal inspector, your local Flight Standards District 
Office. The AMOC approval letter must specifically reference this 
AD.

    Issued in Renton, Washington, on May 5, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-11901 Filed 5-18-10; 8:45 am]
BILLING CODE 4910-13-P
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