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Proposed Rule

Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes

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Information about this document as published in the Federal Register.

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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 737-600, -700, -700C, -800, and -900 series airplanes. This proposed AD would require replacing brackets that hold the P5 panel to the airplane structure, the standby compass bracket assembly, the generator drive and standby power module, and the air conditioning module. This proposed AD also would require, among other actions, inspecting for wire length and for damage of the connectors and the wire bundles, and doing applicable corrective actions if necessary. This proposed AD is prompted by an electrical burning smell in the flight compartment. We are proposing this AD to prevent wire bundles from contacting the overhead dripshield panel and modules in the P5 overhead panel, which could result in electrical arcing and shorting of the electrical connector and consequent loss of several critical systems essential for safe flight.

DATES:

We must receive comments on this proposed AD by June 13, 2005.

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: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
  • By fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-21028; the directorate identifier for this docket is 2004-NM-238-AD.

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FOR FURTHER INFORMATION CONTACT:

Binh Tran, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6485; fax (425) 917-6590.

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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 under ADDRESSES. Include “Docket No. FAA-2005-21028; Directorate Identifier 2004-NM-238-AD” in the subject line 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 submitted 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 can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

We have received reports of an electrical burning smell in the flight compartment. An inspection of the P5 overhead panel found chafed and burned wires. The chafed wires were caused by wire bundle contact with the overhead dripshield panel and modules in the P5 overhead panel, which resulted in electrical arcing and shorting of the electrical connector.

In addition, an investigation at Boeing found that some of the earliest produced Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes delivered from Boeing may have unwanted wire length in the P5 overhead panels. Boeing has made several changes in production to eliminate this condition.

Wire bundle contact with the overhead dripshield panel and modules in the P5 overhead panel, if not corrected, could result in electrical arcing and shorting of the electrical connector and consequent loss of several critical systems essential for safe flight.

Relevant Service Information

We have reviewed Boeing Service Bulletin 737-24A1141, Revision 1, dated December 23, 2004. The service bulletin describes the following procedures:

  • Replacing the five brackets that hold the P5 panel to the airplane structure with new brackets, which includes measuring resistance, and applying bonding agent;
  • Doing a general visual inspection for wire length and for damage of the connectors and the wire bundles; and applicable corrective actions, which includes retying or reterminating the damaged wire bundle and wires that have insufficient length, repairing wire damage, and replacing damaged connectors with new connectors;
  • Installing Teflon/lacing tape and a nylon shield;
  • Making wiring changes;
  • Replacing the standby compass bracket assembly with a new assembly; and
  • Replacing the stud assemblies with new assemblies.

We also have reviewed Boeing Component Service Bulletin 233A3205-24-01, dated July 26, 2001. For certain airplanes, this service bulletin describes procedures for modifying the generator drive and standby power module Start Printed Page 21690assembly, which involves replacing the rear cover and four standoffs with new parts. In addition, we have reviewed Boeing Component Service Bulletin 69-37319-21-02, Revision 1, dated August 30, 2001. For certain other airplanes, this service bulletin describes procedures for modifying the air conditioning module assembly, which involves replacing three plate assemblies, a cover, and two standoffs with new parts. The actions specified in the applicable component service bulletin must be done before or concurrent with the actions specified in Boeing Service Bulletin 737-24A1141 described previously.

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

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. Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 740 airplanes of the affected design in the worldwide fleet and 333 airplanes on the U.S. register.

For all airplanes, the proposed replacements and inspections would take about 16 or 18 work hours per airplane (depending on airplane configuration), at an average labor rate of $65 per work hour. Required parts would cost about $10,231 or $11,139 per airplane (depending on kit). Based on these figures, the estimated cost of the replacements and inspections proposed by this AD is between $3,753,243 and $4,098,897, or between $11,271 and $12,309 per airplane.

For certain airplanes, the modification of the generator drive and standby power module assembly would take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would be provided by the airplane manufacturer at no cost to the operators. Based on these figures, the estimated cost of this modification proposed by this AD is $130 per airplane.

For certain other airplanes, the modification of the air conditioning module assembly would take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Required parts would be provided by the airplane manufacturer at no cost to the operators. Based on these figures, the estimated cost of this modification proposed by this AD is $65 per airplane.

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. See the ADDRESSES section for a location to examine the regulatory evaluation.

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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 airworthiness directive (AD):

Boeing: Docket No. FAA-2005-21028; Directorate Identifier 2004-NM-238-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by June 13, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-24A1141, Revision 1, dated December 23, 2004.

Unsafe Condition

(d) This AD was prompted by an electrical burning smell in the flight compartment. We are issuing this AD to prevent wire bundles from contacting the overhead dripshield panel and modules in the P5 overhead panel, which could result in electrical arcing and shorting of the electrical connector and consequent loss of several critical systems essential for 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.

Inspection/Replacement/Wiring Changes/Corrective Actions

(f) Within 24 months after the effective date of this AD, do the actions in paragraphs (f)(1) through (f)(5) of this AD by accomplishing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-24A1141, Revision 1, dated December 23, 2004. Any applicable corrective actions must be done before further flight.

(1) Replace the five brackets that hold the P5 panel to the airplane structure with new brackets;

(2) Do a general visual inspection for wire length and damage of the connectors and the wire bundles, and applicable corrective actions;

(3) Make wiring changes;

(4) Replace the standby compass bracket assembly with a new assembly; and

(5) Replace the stud assemblies with new assemblies.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of Start Printed Page 21691inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Concurrent Requirements

(g) Before or concurrently with the requirements of paragraph (f) of this AD, do the applicable action specified in Table 1 of this AD.

Table 1.—Concurrent Requirements

For airplanes identified in Boeing component service bulletin—Action—
(1) 233A3205-24-01, dated July 26, 2001Modify the generator drive and standby power module assembly in accordance with the Accomplishment Instructions of the service bulletin.
(2) 69-37319-21-02, Revision 1, dated August 30, 2001Modify the air conditioning module assembly in accordance with the Accomplishment Instructions of the service bulletin.

Alternative Methods of Compliance (AMOCs)

(h) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Start Signature

Issued in Renton, Washington, on April 18, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 05-8403 Filed 4-26-05; 8:45 am]

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