Document ID: FAA-2008-0376-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 747-100, 747-200B, 747- 300, and 747SR Series Airplanes
Posted Date: 2008-04-01T04:00Z

[Federal Register: April 1, 2008 (Volume 73, Number 63)]
[Proposed Rules]               
[Page 17258-17260]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01ap08-10]                         

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================

[[Page 17258]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0376; Directorate Identifier 2007-NM-322-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-100, 747-200B, 747-
300, and 747SR 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 
certain Boeing Model 747-100, 747-200B, 747-300, and 747SR series 
airplanes that have been converted by Boeing to the Boeing Special 
Freighter configuration. This proposed AD would require installation of 
a closeout panel and moisture curtains for the main equipment center. 
This proposed AD would also require changing the drain tubes for the 
power drive units and the pitot static tubes and installing larger 
moisture shrouds. This proposed AD results from a report of water 
contamination in the electrical and electronic units in the main 
equipment center. We are proposing this AD to prevent the malfunction 
of one or more electrical and electronic units in the main equipment 
center, which could adversely affect the airplane's continued safe 
flight.

DATES: We must receive comments on this proposed AD by May 16, 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 Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

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-2008-0376; 
Directorate Identifier 2007-NM-322-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 water contamination in the electrical 
and electronic units in the main equipment center. The water 
contamination caused a central air data computer (CADC-2) and an air 
data inertial reference unit (ADIRU-1) to malfunction with eight 
cockpit indications of failure. When loading cargo in rain or snow 
conditions, water can spill onto the main deck cargo floor and flow 
through the power drive units (PDUs). If the amount of water exceeds 
the drain capacity of the PDUs above the main equipment center, water 
can spill onto the electrical and electronic units. This water 
contamination could cause one or more of the approximately 80 
electrical and electronic units to malfunction. The malfunction of one 
or more electrical and electronic units in the main equipment center, 
if not corrected, could adversely affect the airplane's continued safe 
flight.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-25A3368, 
Revision 1, dated June 25, 2007. The service bulletin describes 
procedures for installing a closeout panel and moisture curtains to 
protect the electrical and electronic units in the main equipment 
center from water contamination.
    We have also reviewed Boeing Alert Service Bulletin 747-25A3346, 
dated September 13, 2007. The service bulletin describes procedures for 
changing the PDU drain tubes and pitot static tubes, and installing 
larger moisture shrouds to provide additional protection from water 
contamination. Operators should note that accomplishing the actions 
specified in Boeing Alert Service Bulletin 747-25A3346 concurrently 
with the actions specified in Boeing Alert Service Bulletin 747-25A3368 
would necessitate less work than accomplishing the service bulletins at 
different times.

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(se) same type 
design(s). This proposed AD would require accomplishing the

[[Page 17259]]

actions specified in the service information described previously.

Clarification of Service Information

    Boeing Alert Service Bulletin 747-25A3346 specifies prior or 
concurrent accomplishment of Boeing Alert Service Bulletin 747-25A3368, 
dated August 25, 2005, or Revision 1, dated June 25, 2007. However, 
this proposed AD would allow accomplishment of the original issue of 
Boeing Alert Service Bulletin 747-25A3368 before the effective date of 
the proposed AD only if the additional work specified in Revision 1 of 
the service bulletin is accomplished.

Costs of Compliance

    We estimate that this proposed AD would affect 42 airplanes of U.S. 
registry. The following table provides the estimated costs, at an 
average labor rate of $80 per work hour, for U.S. operators to comply 
with this proposed AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Number of
                                                                       Cost per        U.S.-
            Action                Work hours           Parts           product       registered     Fleet cost
                                                                                     airplanes
----------------------------------------------------------------------------------------------------------------
Installation for Boeing Alert  Up to 10........  Up to $11,672...  Up to $12,472..           42  Up to $523,824.
 Service Bulletin 747-25A3368.
Installation for Boeing Alert  Up to 62........  Up to $31,621...  Up to $36,581..           42  Up to
 Service Bulletin 747-25A3346.                                                                    $1,536,402.
----------------------------------------------------------------------------------------------------------------

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, 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:

Boeing: Docket No. FAA-2008-0376; Directorate Identifier 2007-NM-
322-AD.

Comments Due Date

    (a) We must receive comments by May 16, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 747-100, 747-200B, 747-300, 
and 747SR series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 747-25A3346, dated 
September 13, 2007; and Boeing Alert Service Bulletin 747-25A3368, 
Revision 1, dated June 25, 2007.

    Note 1: The affected airplanes are those that have been 
converted by Boeing to the Boeing Special Freighter configuration.

Unsafe Condition

    (d) This AD results from a report of water contamination in the 
electrical and electronic units in the main equipment center. We are 
issuing this AD to prevent the malfunction of one or more electrical 
and electronic units in the main equipment center, which could 
adversely affect the airplane's continued safe flight.

Compliance

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

Installation of Closeout Panel and Moisture Curtains

    (f) For the airplanes identified in Boeing Alert Service 
Bulletin 747-25A3368, Revision 1, dated June 25, 2007: Within 24 
months after the effective date of this AD, install the closeout 
panel and moisture curtains for the main equipment center, by 
accomplishing all of the applicable actions specified in the 
Accomplishment Instructions of the service bulletin.

Installation of Larger Moisture Shrouds and Additional Drain Lines

    (g) For the airplanes identified in Boeing Alert Service 
Bulletin 747-25A3346, dated September 13, 2007: Within 72 months 
after the effective date of this AD, change the drain tubes for the 
power drive units and the pitot static tubes and install larger 
moisture shrouds, by accomplishing all of the applicable actions 
specified in the Accomplishment Instructions of the service 
bulletin.

    Note 2: Accomplishing the actions specified in Boeing Alert 
Service Bulletin 747-25A3346 dated September 13, 2007, concurrently 
with the actions specified in Boeing Alert Service Bulletin 747-
25A3368, Revision 1, dated June 25, 2007, would necessitate less 
work than accomplishing the service bulletins at different times.

Credit for Actions Done According to Previous Issue of the Service 
Bulletin

    (h) Actions done before the effective date of this AD in 
accordance with Boeing Alert

[[Page 17260]]

Service Bulletin 747-25A3368, dated August 25, 2005, are acceptable 
for compliance with the corresponding actions required by paragraph 
(f) of this AD, provided that all of the additional work specified 
in Boeing Alert Service Bulletin 747-25A3368, Revision 1, dated June 
25, 2007, is accomplished in accordance with paragraph (f) of this 
AD.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
ATTN: Marcia Smith, Aerospace Engineer, Cabin Safety and 
Environmental Systems Branch, ANM-150S, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6484; fax (425) 
917-6590; 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 March 24, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-6613 Filed 3-31-08; 8:45 am]

BILLING CODE 4910-13-P