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Proposed Rule

Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Boeing Model 737-300, -400, and -500 series airplanes. The existing AD currently requires repetitive inspections of certain connectors located in the main wheel well to detect discrepancies, and corrective action if necessary. This proposed AD would instead mandate a modification. This proposed AD is prompted by the development of a modification intended to address the unsafe condition. We are proposing this AD to prevent discrepancies of certain connectors located in the main wheel well. Those discrepancies could result in electrical arcing of the connectors, uncommanded closure of the engine fuel shut-off valves, and consequent in-flight loss of thrust or engine shutdown from lack of fuel.

DATES:

We must receive comments on this proposed AD by December 20, 2004.

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.
  • 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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Technical information: Stephen Oshiro, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6480; fax (425) 917-6590.

Plain language information: Marcia Walters, marcia.walters@faa.gov.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19531; Directorate Identifier 2004-NM-45-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. Start Printed Page 64540Using the search function of our docket 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 the 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.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.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

On July 2, 2001, the FAA issued AD 2001-14-06, amendment 39-12316 (66 FR 36445, July 12, 2001), for all Boeing Model 737-300, -400, and -500 series airplanes. That AD requires repetitive inspections of certain connectors located in the main wheel well to detect discrepancies, and corrective action if necessary. That AD was prompted by reports indicating engine shutdown during flight due to uncommanded movement of the engine fuel shutoff valve. We issued that AD to detect and correct discrepancies of certain connectors located in the main wheel well, which could result in electrical arcing of the connectors, uncommanded closure of the engine fuel shut-off valves, and consequent in-flight loss of thrust or engine shutdown from lack of fuel.

Actions Since Existing AD Was Issued

Since we issued AD 2001-14-06, the manufacturer has developed a modification intended to address the unsafe condition. The modification was developed after operators of Model 737 series airplanes reported additional incidents of short circuits between the electrical contacts in the connectors located in the main wheel well. One incident involved turning the airplane around and returning to the airport due to smoke in the cockpit. The smoke emission was from the P5-2 fuel system module located in the overhead panel, and was caused by a short circuit. These operators had previously complied with the actions required by the existing AD. This has led us to determine that the currently required actions do not address the unsafe condition. A short between the outboard landing light and the engine fuel shut-off valve circuits could result in uncommanded closure of the engine fuel shut-off valves, and consequent in-flight loss of thrust or engine shutdown from lack of fuel.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 737-28-1196, Revision 3, dated April 1, 2004. The service bulletin describes procedures for modification of the two electrical connectors located in the main wheel well. The modification includes, but is not limited to: Performing a close visual inspection of the plug and receptacle connectors for discrepancies (contamination, corrosion, heat discoloration, arcing, and other damage), and replacing with new connectors if any discrepancy is found.

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 products of this same type design. Therefore, we are proposing this AD, which would supersede AD 2001-14-06. This proposed AD would mandate a modification of the two electrical connectors in the main wheel well. This proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Difference Between the Proposed AD and Service Bulletin.”

Differences Between the Proposed AD and Service Bulletin

The 18-month compliance time required by this proposed AD is the result of a technical discussion between the FAA and the airplane manufacturer. Boeing Special Attention Service Bulletin 737-28-1196, Revision 3, dated April 1, 2004, erroneously specifies a 6-month compliance time. In light of this error, the compliance times of the existing AD, and technical discussions with the manufacturer, we are proposing less restrictive compliance requirements in this AD. For airplanes that have been inspected in accordance with AD 2001-14-16, the modification would be required within 18 months after the last inspection per AD 2001-14-16, or within 6 months after the effective date of this AD, whichever is later. For airplanes that have not been inspected in accordance with AD 2001-14-16 as of the effective date of this AD, the modification would be required within 12 months after the effective date of this AD. These compliance times represent an appropriate interval of time for affected airplanes to continue to operate without compromising safety.

The service bulletin refers only to a “close visual inspection” for discrepancies of the plug and receptacle connectors. We have determined that the procedures in the service bulletin should be described as a “general visual inspection.”

Costs of Compliance

There are about 1,974 Model 737-300, -400, and -500 airplanes worldwide of the affected design. This proposed AD would affect about 755 airplanes of U.S. registry.

The new proposed modification (including the operational tests) would take about 9 work hours per airplane, at an average labor rate of $65 per work hour. Required parts cost would be minimal. Based on these figures, the estimated cost of the modification specified in this proposed AD for U.S. operators is $441,675, or $585 per airplane.

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.Start Printed Page 64541

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.

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:

Start Authority

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

End Authority
[Amended]

2. The FAA amends § 39.13 by removing 39-12316 (66 FR 36445, July 12, 2001) and adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2004-19531; Directorate Identifier 2004-NM-45-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this airworthiness directive (AD) action by December 20, 2004.

Affected ADs

(b) This AD supersedes AD 2001-14-06, amendment 39-12316.

Applicability

(c) This AD applies to all Boeing Model 737-300, -400, and -500 series airplanes, certificated in any category.

Unsafe Condition

(d) This AD was prompted by the development of a modification intended to address the unsafe condition. We are issuing this AD to detect and correct discrepancies of certain connectors located in the main wheel well. Those discrepancies could result in electrical arcing of the connectors, uncommanded closure of the engine fuel shut-off valves, and consequent in-flight loss of thrust or engine shutdown from lack of fuel.

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.

Modification

(f) At the applicable time specified in paragraph (f)(1) or (f)(2) of this AD: Modify the electrical connectors located in the main wheel well by doing all the actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-28-1196, Revision 3, dated April 1, 2004. Any corrective action must be done before further flight in accordance with the service bulletin.

(1) For airplanes on which no inspection required by AD 2001-14-06 has been done as of the effective date of this AD: Accomplish the modification within 12 months after the effective date of this AD.

(2) For airplanes on which any inspection required by AD 2001-14-06 has been done as of the effective date of this AD: Accomplish the modification at the later of the times specified in paragraph (f)(2)(i) or (f)(2)(ii) of this AD.

(i) Within 18 months after accomplishing the last inspection.

(ii) Within 6 months after the effective date of this AD.

Modifications Done Using Previous Issues of the Service Bulletin

(g) Modifications done before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737-28-1196, dated December 5, 2002; Revision 1, dated March 13, 2003; or Revision 2, dated August 21, 2003; are considered acceptable for compliance with paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(h)(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) Alternative methods of compliance, approved previously in accordance with AD 2001-14-06, amendment 39-12316, are approved as AMOCs for this AD.

Start Signature

Issued in Renton, Washington, on October 26, 2004.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 04-24719 Filed 11-4-04; 8:45 am]

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