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Proposed Rule

Airworthiness Directives; Boeing Model 747-100, 747-200B, 747-300, and 747SR Series Airplanes

Document Details

Information about this document as published in the Federal Register.

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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.

Start Further Info

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.

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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 Start Printed Page 17259actions 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

ActionWork hoursPartsCost per productNumber of U.S.- registered airplanesFleet cost
Installation for Boeing Alert Service Bulletin 747-25A3368Up to 10Up to $11,672Up to $12,47242Up to $523,824.
Installation for Boeing Alert Service Bulletin 747-25A3346Up to 62Up to $31,621Up to $36,58142Up to $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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

2. The FAA amends § 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 Start Printed Page 17260Service 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.

Start Signature

Issued in Renton, Washington, on March 24, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. E8-6613 Filed 3-31-08; 8:45 am]

BILLING CODE 4910-13-P