
[Federal Register Volume 77, Number 43 (Monday, March 5, 2012)]
[Proposed Rules]
[Pages 13043-13046]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-5180]


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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 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain The Boeing Company Model 747-400 and 747-400D series 
airplanes. That NPRM proposed 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. That NPRM also provided 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. That NPRM was prompted by a report 
of a multi-power system loss in flight of 1, 2, and 
3 alternating current electrical power systems located in the 
MEC. This action revises that NPRM by revising the locating dimensions 
of the brackets and changing the routing of the forward drain tubes. We 
are proposing this supplemental NPRM to prevent water penetration into 
the MEC, which could result in the loss of flight critical systems. 
Since these actions impose an additional burden over that proposed in 
the NPRM, we are reopening the comment period to allow the public the 
chance to comment on these proposed changes.

DATES: We must receive comments on this supplemental NPRM by April 19, 
2012.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, 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 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; email 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: Francis Smith, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 
98057-3356; phone: 425-917-6596; fax: 425-917-6590; email: 
francis.smith@faa.gov.

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 issued an NPRM to amend 14 CFR part 39 to include an AD that 
would apply to Model 747-400 and 747-400D series airplanes. That NPRM 
was published in the Federal Register on May 19, 2010 (75 FR 27966). 
That NPRM proposed to require installing aluminum gutter reinforcing 
brackets to

[[Page 13044]]

the forward and aft drip shield gutters of the 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. That NPRM also provided 
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.

Actions Since Previous NPRM (75 FR 27966, May 19, 2010) Was Issued

    Since we issued the previous NPRM (75 FR 27966, May 19, 2010), 
difficulties were found in accessing areas for repair due to a service 
bulletin error. We have determined that changing the locating 
dimensions of support brackets and re-routing the forward drain tubes 
are necessary due to interference with an existing pitot/static shroud.

Comments

    We gave the public the opportunity to comment on the previous NPRM 
(75 FR 27966, May 19, 2010). The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Reference Revised Service Information

    Boeing requested that we refer to Boeing Alert Service Bulletin 
747-25A3555, Revision 1, dated July 27, 2011, which includes steps to 
take into account an interference issue found during part installation.
    We agree to update the references in this supplemental NPRM to 
Boeing Alert Service Bulletin 747-25A3555, Revision 1, dated July 27, 
2011. (The previous NPRM (75 FR 27966, May 19, 2010) refers to Boeing 
Alert Service Bulletin 747-25A3555, dated November 4, 2009.) Paragraphs 
(c) and (g) of this supplemental NPRM have been updated to refer to 
Boeing Alert Service Bulletin 747-25A3555, Revision 1, dated July 27, 
2011. Boeing Alert Service Bulletin 747-25A3555, Revision 1, dated July 
27, 2011, revises the locating dimensions of the brackets and changes 
the routing of the forward drain tubes due to difficulties in accessing 
areas for repair. It also revises the airplane groups.

Request To Remove Parts Installed During Interim Action

    Delta Air Lines requested provisions in the previous NPRM (75 FR 
27966, May 19, 2010) to electively remove the stanchions, fittings, and 
tubing installed when doing the interim action, after completing the 
terminating inspection, repair, and fiberglass overlay reinforcement on 
the top surface of the drip shields. Delta Air Lines stated that these 
items add 26 pounds to the weight of the aircraft, and if the interim 
action is optional, it may be removed once the terminating action is 
implemented.
    We disagree with the request. We have determined that removal of 
the hardware installed to the MEC area during the interim action poses 
concerns on the effect on the protection offered by the terminating 
action (overcoat layer). Removing the hardware could compromise the 
seals by creating disbonded seams and reopening cracks in the MEC 
polycarbonate casing, and could result in other damage. Although the 
interim action is optional, it should be considered a permanent 
installation once performed. It should be noted that doing both the 
interim and terminating actions provides two layers of water protection 
to the MEC, which greatly minimizes the issue of future water 
contamination. We have discussed this issue with Boeing. No change has 
been made to the supplemental NPRM in this regard.

Request To Clarify Material Composition of MEC Drip Shield Gutter

    Boeing requested that we change the wording of paragraphs (g)(1) 
and (g)(2)(i) of the previous NPRM (75 FR 27966, May 19, 2010) from 
``MEC drip shield aluminum gutter'' to ``aluminum reinforcing brackets 
on the MEC drip shield gutter'' to clarify that the original drip 
shield gutter is composite material and the reinforcement material is 
aluminum.
    We agree with the request and have changed paragraphs (g)(1) and 
(g)(2)(i) of this supplemental NPRM accordingly.

Request To Change Parts Costs

    Boeing requested that we revise the previous NPRM (75 FR 27966, May 
19, 2010) to change the parts costs associated with installing the 
brackets and adding the overcoat. Boeing stated that the parts costs 
for the aluminum reinforcing bracket kit is $2,408 instead of ``none'' 
as specified in the previous NPRM. Boeing also stated that the parts 
costs for the fiberglass reinforcement is $1,731 (3 panels x $577/
panel) plus the cost of fiberglass, resin, and repair materials for 
cracks and holes in the drip shield instead of ``none'' as mentioned in 
the previous NPRM.
    We agree with the request and have changed the ``Estimated costs'' 
table of this AD accordingly. However, because the costs for parts 
required for bracket installation depends on the work package, we have 
stated the cost as ``Up to $2,408'' in the ``Estimated costs'' table of 
this supplemental NPRM.

FAA's Determination

    We are proposing this supplemental NPRM 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. Certain changes described above expand the scope of the 
original NPRM (75 FR 27966, May 19, 2010). As a result, we have 
determined that it is necessary to reopen the comment period to provide 
additional opportunity for the public to comment on this supplemental 
NPRM.

Proposed Requirements of the Supplemental NPRM

    This supplemental NPRM would require accomplishing the actions 
specified in Boeing Alert Service Bulletin 747-25A3555, Revision 1, 
dated July 27, 2011, as described previously.

Costs of Compliance

    We estimate that this proposed AD affects 71 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
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                                                                                                Cost on U.S.
            Action                Labor cost         Parts cost         Cost per product          operators
----------------------------------------------------------------------------------------------------------------
Install Brackets.............  19 work-hours x  Up to $2,408 \1\....  Up to $4,023 \1\....  Up to $285,633.\1\
                                $85 per hour =
                                $1,615.
Add Overcoat.................  63 work hours x  $1,731..............  $7,086..............  $503,106.
                                $85 per hour =
                                $5,355 ($577 x
                                3).

[[Page 13045]]

 
Install Optional MEC Drip      22 work hours x  Up to $8,982 \1\....  Up to $10,852 \1\...  Up to $770,492.\1\
 Shield Drain System.           $85 per hour =
                                $1,870.
----------------------------------------------------------------------------------------------------------------
\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),
    (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-2010-0480; Directorate Identifier 
2010-NM-035-AD.

(a) Comments Due Date

    We must receive comments by April 19, 2012.

(b) Affected ADs

    None.

(c) Applicability

    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, Revision 1, dated July 
27, 2011.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of a multi-power system loss in 
flight of 1, 2, and 3 alternating current 
electrical power systems located in the main equipment center (MEC). 
We are issuing this AD to prevent water penetration into the MEC, 
which could result in loss of flight critical systems.

(f) Compliance

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

(g) Modification

    Do the actions specified in either paragraph (g)(1) or (g)(2) of 
this AD.
    (1) Within 24 months after the effective date of this AD, 
install aluminum reinforcing brackets on the MEC drip shield gutter, 
in accordance with Work Package 1 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 747-25A3555, Revision 1, dated July 
27, 2011; 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 Boeing 
Alert Service Bulletin 747-25A3555, Revision 1, dated July 27, 2011. 
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 aluminum reinforcing brackets on the MEC drip shield gutter, 
in accordance with Work Package 1 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 747-25A3555, Revision 1, dated July 
27, 2011; and install a MEC drip shield drain system, in accordance 
with Work Package 2 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-25A3555, Revision 1, dated July 27, 2011.
    (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 Boeing Alert Service Bulletin 
747-25A3555, Revision 1, dated July 27, 2011. Do all applicable 
corrective actions before further flight after doing the general 
visual inspection.

(h) Alternative Methods of Compliance (AMOCs)

    (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 emailed 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.

(i) Related Information

    (1) For more information about this AD, contact Francis Smith, 
Aerospace Engineer, Cabin Safety and Environmental Systems

[[Page 13046]]

Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 
Lind Avenue SW., Renton, Washington 98057-3356; phone: 425-917-6596; 
fax: 425-917-6590; email: francis.smith@faa.gov.
    (2) 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; email 
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 24, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-5180 Filed 3-2-12; 8:45 am]
BILLING CODE 4910-13-P


