E7-16117. Airworthiness Directives; Boeing Model 747-200C and -200F Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-200C and -200F series airplanes. This proposed AD would require, among other actions, installing mounting brackets, support angles, and moisture curtains in the main 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 of the electrical/electronic units, which could cause the electrical/electronic units to malfunction, and as a consequence, could adversely affect the airplane's continued safe flight.

DATES:

We must receive comments on this proposed AD by October 1, 2007.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• 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.
• Fax: [phone].
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

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 submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-28924; Directorate Identifier 2007-NM-051-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located on the ground level of the West Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received reports of water contamination in the electrical/electronic units in the main equipment center, on Boeing Model 747-200C and -200F series airplanes. The water contamination resulted in malfunctions and the replacement of multiple electrical/electronic units in the main equipment center. In one case, these malfunctions resulted in an air turn back, high pilot workload, and minimal cockpit indication. Water contamination of the electrical/electronic units, if not corrected, could cause the electrical/electronic units to malfunction, and as a consequence, could adversely affect the airplane's continued safe flight.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007. This service information describes procedures for installing mounting brackets, support angles, and moisture curtains in the main equipment center.

We also have reviewed Boeing Alert Service Bulletin 747-38A2073, Revision 3, dated May 22, 2003. This service information describes procedures for installing drip shields (including a drip pan assembly, drain tubing, and attaching hardware) over the forward, outboard halves of the E1-1 and E3-1 shelves in the main equipment bay.

For certain airplanes, the actions specified in Boeing Alert Service Bulletin 747-38A2073, Revision 3, dated May 22, 2003; Revision 2, dated April 26, 2001; Revision 1, dated June 21, 1990; or Original Release, dated November 30, 1989; must be done prior to or concurrently with the actions specified in Boeing Alert Service Bulletin 747-25A3430. (AD 2001-24-30, amendment 39-12547 (66 FR 64104, December 12, 2001) requires installing drip shields in accordance with Boeing Alert Service Bulletin 747-38A2073, Revision 2, or in accordance with Revision 1 or Original Release if done before the effective date of that AD.)

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Interim Action

This is considered to be interim action. The manufacturer has advised that it currently is developing another modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA might consider additional rulemaking.

Costs of Compliance

There are about 79 airplanes of the affected design in the worldwide fleet. 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 airplane	Number of U.S.-registered airplanes	Fleet cost
Installation	3	$80	$8,960	$9,200	25	$230,000
Prior to or concurrent requirements of AD 2001-24-30	32	80	4,497	7,057	25	176,425

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 have 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 that the 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

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.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-28924; Directorate Identifier 2007-NM-051-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 1, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-200C and -200F series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007.

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 of the electrical/electronic units, which could cause the electrical/electronic units to malfunction, and as a consequence, could adversely affect the airplane's continued safe flight.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Installations

(f) Within 24 months after the effective date of this AD, install mounting brackets, support angles, and moisture curtains in the main equipment center, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007.

Prior or Concurrent Requirements

(g) For airplanes identified as Group 1 and Group 3 airplanes in Boeing Alert Service Bulletin 747-25A3430, dated February 15, 2007: Prior to or concurrently with the requirements of paragraph (f) of this AD, install drip shields (including a drip pan assembly, drain tubing, and attaching hardware) over the forward, outboard halves of the E1-1 and E3-1 shelves in the main equipment bay, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-38A2073, Revision 3, dated May 22, 2003.

(h) Installation of drip shields before the effective date of this AD in accordance with paragraph (a) and Note 2 of AD 2001-24-30, amendment 39-12547, is acceptable for compliance with the corresponding actions in paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with 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 July 30, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.