E9-312. Airworthiness Directives; Boeing Model 747-200C and 747-200F 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 747-200C and 747-200F series airplanes. This proposed AD would require installing larger moisture shrouds and additional drain lines in the electrical/electronic equipment center. This proposed AD results from reports of water contamination in the electrical/electronic units in the main equipment center. We are proposing this AD to prevent water contamination in the electrical/electronic units in the main equipment center, which could result in an electrical short and potential loss of several functions essential for safe flight.

DATES:

We must receive comments on this proposed AD by February 26, 2009.

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: [phone].
• 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; telephone [phone]; fax [phone]; e-mail [e-mail]; 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 or 425-227-1152.

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 [phone]) 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 [phone]; fax [phone].

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-2008-1362; Directorate Identifier 2008-NM-150-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 reports of water contamination in the electrical/electronic units in the main equipment center. Loading cargo in rain or snow conditions can allow a large amount of water into the airplane on the cargo or open main deck doors. The 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 located above the main equipment center, water can spill onto the electrical/electronic units. Water contamination in the electrical/electronic units in the main equipment center could result in an electrical short and potential loss of several functions essential for safe flight.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008. This service bulletin describes procedures for installing larger moisture shrouds and additional drain lines in the electrical/electronic equipment center that provide protection from water contamination in the main equipment center. The procedures include:

• Changing the PDU drain tubes;
• Changing the pitot static tubes;
• Replacing moisture curtains and support brackets;
• Reworking base line (BL) 11 intercostals;
• Installing new moisture shrouds; and
• Relocating the wire bundle, lights, ground bracket, and disconnect bracket of the main equipment center.

Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007, is necessary to be accomplished prior to or concurrent with Boeing Alert Service Bulletin 747-25A3431. Boeing Alert Service Bulletin 747-25A3430 describes procedures for installing protective moisture curtains in the main equipment center.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

Related AD

AD 2007-26-03, amendment 39-15305 (72 FR 71218, December 17, 2007), applies to the airplanes affected by this NPRM. That AD requires, among other actions, installation of mounting brackets, support angles, and moisture curtains in the main equipment center in accordance with Boeing Alert Service Bulletin 747-25A3430.

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 25 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per product	Number of U.S.- registered airplanes	Fleet cost
Installation	Up to 75	$80	Up to $28,405	Up to $34,405	25	Up to $860,125.

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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

Boeing: Docket No. FAA-2008-1362; Directorate Identifier 2008-NM-150-AD.

Comments Due Date

(a) We must receive comments by February 26, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-200C and 747-200F series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008.

Unsafe Condition

(d) This AD results from reports of water contamination in the electrical/electronic units in the main equipment center. We are issuing this AD to prevent water contamination in the electrical/electronic units in the main equipment center, which could result in an electrical short and potential loss of several functions essential for safe flight.

Compliance

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

Installation

(f) Within 72 months after the effective date of this AD, install larger moisture shrouds and additional drain lines, by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3431, dated March 6, 2008.

Prior or Concurrent Action

(g) Prior to or concurrently with accomplishing the actions required by paragraph (f) of this AD: Install protective moisture curtains in the main equipment center in accordance with Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007.

Note 1:

The installation required by paragraph (g) of this AD is also required by paragraph (f) of AD 2007-26-03, amendment 39-15305, for Boeing Model 747-200C and -200F series airplanes.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, 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 [phone]; fax [phone]; 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 December 18, 2008.

Stephen P. Boyd,

Assistant Manager, Transport Airplane Directorate, Aircraft Certification Service.