
[Federal Register Volume 76, Number 28 (Thursday, February 10, 2011)]
[Proposed Rules]
[Pages 7513-7515]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-2952]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0041; Directorate Identifier 2010-NM-227-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 747-400 and -
400F 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 the 
products listed above. This proposed AD would require a general visual 
inspection for cracks and holes of the main equipment center (MEC) drip 
shields, and repairs if necessary; installation of a fiberglass 
reinforcing overcoat; and, for certain airplanes, installation of 
stiffening panels to the MEC drip shields. This proposed AD was 
prompted by a report of a loss of bus control unit number 1 and 
generator control units numbers 1 and 2 while the airplane was on the 
ground, and multiple operator reports of cracked MEC drip shields. 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 March 28, 2011.

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, 
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 (phone: 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 & Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; phone: 425-917-6484; fax: 425-917-6590; e-mail: 
marcia.smith@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-2011-0041; 
Directorate Identifier 2010-NM-227-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 have received a report of a loss of bus control unit number 1 
and generator control units numbers 1 and 2 while the airplane was on 
the ground, and multiple operators have reported cracked main equipment 
center (MEC) drip shields. Cracking in the MEC drip shield and exhaust 
plenum has been identified as part of the water leak path into the MEC. 
This condition, if not corrected, could result in water penetration 
into the MEC, which could result in the loss of flight critical 
systems.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 747-25A3588, dated July 
19, 2010. The service information describes procedures for performing a 
general visual inspection of the MEC drip shield for cracks and holes, 
performing repairs if necessary, and installing a fiberglass 
reinforcing overcoat to the MEC drip shield. Additionally, for 
airplanes identified as Groups 1 and 3, the service information 
describes procedures for installing MEC drip shield panel stiffeners.

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

[[Page 7514]]

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 affects 41 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
              Action                      Labor cost              Parts cost          product        operators
----------------------------------------------------------------------------------------------------------------
Inspection and installation:       20 work-hours x $85 per   $1,109.............          $2,809         $67,416
 Groups 1, 3 (24 airplanes).        hour = $1,700.
Inspection and installation:       17 work-hours x $85 per   Negligible.........           1,445          24,565
 Group 2 (17 airplanes).            hour = $1,445.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs that 
would be required based on the results of the proposed inspection. We 
have no way of determining the number of aircraft that might need these 
repairs.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
             Action                      Labor cost              Parts cost             Cost per airplane
----------------------------------------------------------------------------------------------------------------
Hole repair.....................  1 work-hour x $85 per     Negligible.........  $85 per hole.
                                   hour = $85 per hole.
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    According to the manufacturer, some of the costs of this proposed 
AD may be covered under warranty, thereby reducing the cost impact on 
affected individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

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):

The Boeing Company: Docket No. FAA-2011-0041; Directorate Identifier 
2010-NM-227-AD.

Comments Due Date

    (a) We must receive comments by March 28, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 747-400 and -
400F series airplanes, certificated in any category, as identified 
in Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010.

Subject

    (d) Joint Aircraft System Component (JASC)/Air Transport 
Association (ATA) of America Code 25, Equipment/Furnishings.

Unsafe Condition

    (e) This AD was prompted by a report of a loss of bus control 
unit number 1 and generator control units numbers 1 and 2 while the 
airplane was on the ground, and multiple operator reports of cracked 
main equipment center (MEC) drip shields. We are issuing this AD to 
prevent water penetration into the MEC, which could result in the 
loss of flight critical systems.

Compliance

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

Inspection

    (g) Within 24 months after the effective date of this AD, do the 
actions specified in paragraph (g)(1) or (g)(2) of this AD, as 
applicable, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-25A3588, dated July 19, 2010.
    (1) For Group 1 and Group 3 airplanes, as identified in Boeing 
Alert Service Bulletin 747-25A3588, dated July 19, 2010: Do a 
general visual inspection of the MEC drip

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shield to detect cracking and holes; do all applicable repairs; and 
install the MEC drip shield panel stiffeners and the fiberglass 
reinforcing overcoat to the MEC drip shield; in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
25A3588, dated July 19, 2010. Do all applicable repairs before 
further flight.
    (2) For Group 2 airplanes, as identified in Boeing Alert Service 
Bulletin 747-25A3588, dated July 19, 2010: Do a general visual 
inspection of the MEC drip shield to detect cracking and holes; do 
all applicable repairs; and install the fiberglass reinforcing 
overcoat to the MEC drip shield; in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
25A3588, dated July 19, 2010. Do all applicable repairs before 
further flight.

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. 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. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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.

Related Information

    (i) For more information about this AD, contact Marcia Smith, 
Aerospace Engineer, Cabin Safety & Environmental Systems Branch, 
ANM-150S FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind 
Avenue, SW., Renton, Washington 98057-3356; phone: 425-917-6484; 
fax: 425-917-6590; e-mail: marcia.smith@faa.gov.
    (j) For service information identified in this 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.

    Issued in Renton, Washington, on February 3, 2011.
Ali Bahrami,
Manager,Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011-2952 Filed 2-9-11; 8:45 am]
BILLING CODE 4910-13-P


