E6-13730. Airworthiness Directives; Boeing Model 757 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 757 airplanes. This proposed AD would require inspecting certain power feeder wire bundles for damage, inspecting the support clamps for these wire bundles to determine whether the clamps are properly installed, and performing corrective actions if necessary. This proposed AD results from a report that a power feeder wire bundle chafed against the number six auxiliary slat track, causing electrical wires in the bundle to arc, which damaged both the auxiliary slat track and power feeder wires. We are proposing this AD to prevent arcing that could be a possible ignition source for leaked flammable fluids, which could result in a fire. Arcing could also result in a loss of power from the generator connected to the power feeder wire bundle, and consequent loss of systems, which could reduce controllability of the airplane.

DATES:

We must receive comments on this proposed AD by October 5, 2006.

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: [phone].
• 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.

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:

Philip Sheridan, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, 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-2006-25642; Directorate Identifier 2006-NM-121-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 Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) 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 Docket Management System receives them.

Discussion

We have received a report indicating that a power feeder wire bundle chafed against the number six auxiliary slat track at front spar station (FSS) 148.90 on a Boeing Model 757 airplane. Two of the three phases of the power feeder wire bundle were worn to the conductor. The chafing caused electrical wires in the bundle to arc, which damaged both the auxiliary slat track and power feeder wires. Investigation revealed that the support clamp for the power feeder wire bundle was not properly installed in the attach bracket, which resulted in insufficient clearance between the power feeder wire bundle and the auxiliary slat track. Arcing of the electrical wires in the power feeder wire bundle could be a possible ignition source for leaked flammable fluids, which could result in a fire. Arcing could also result in a loss of power from the generator connected to the power feeder wire bundle, and consequent loss of systems which could reduce controllability of the airplane.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletins 757-24-0105 and 757-24-0106, both Revision 2, both dated April 20, 2006. The service bulletins describe procedures for inspecting for damage (including but not limited to chafing) of power feeder wire bundles W3312 and W3412 at FSS 148.90 in the left and right wings; inspecting support clamps for these wire bundles to determine whether the clamps are properly installed in the attach bracket; and performing corrective actions if necessary.

For airplanes identified as Group 1 in Special Attention Service Bulletin 757-24-0105, proper installation in the left wing consists of the support clamp being installed in the upper hole of the lower attach bracket, with the lobe of the support clamp installed in the “up” position. Proper installation in the right wing on Group 1 airplanes consists of the support clamp being installed in the lower hole of the support bracket. For airplanes other than those in Group 1, proper installation on both wings consists of the support clamp being installed in the lower hole of the attach bracket.

Corrective actions are as follows:

• Repairing any damage of the power feeder wire bundles.
• Installing in the correct hole of the attach bracket any support clamp found installed elsewhere, and installing a spacer if one is not already installed.
• Installing a rivet to plug the open hole in the attach bracket.

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

Clarification of Inspection Terminology

The service bulletins include the instruction to inspect the wire bundles and support clamps, but the Work Instructions do not specifically state what type of inspection is necessary. However, the term “general visual inspection” is defined under paragraph 3.A., General Information, in the Accomplishment Instructions of the service bulletins. Thus, this proposed AD refers to these inspections as “general visual inspections.”

Costs of Compliance

There are about 902 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 631 airplanes of U.S. registry. The proposed actions would take about 2 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $100,960, or $160 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 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-2006-25642; Directorate Identifier 2006-NM-121-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 5, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes; certificated in any category; as identified in the service bulletins listed in Table 1 of this AD.

Table 1.—Applicability

Airplane model	Boeing Special Attention Service Bulletin	Revision level	Date
757-200, -200PF, -200CB series	757-24-0105	2	April 20, 2006.
757-300 series	757-24-0106	2	April 20, 2006.

Unsafe Condition

(d) This AD results from a report that a power feeder wire bundle chafed against the number six auxiliary slat track, causing electrical wires in the bundle to arc, which damaged both the auxiliary slat track and power feeder wires. We are issuing this AD to prevent arcing that could be a possible ignition source for leaked flammable fluids, which could result in a fire. Arcing could also result in a loss of power from the generator connected to the power feeder wire bundle, and consequent loss of systems, which could reduce controllability of the airplane.

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.

Service Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For Model 757-200, -200PF, and -200CB series airplanes: Boeing Special Attention Service Bulletin 757-24-0105, Revision 2, dated April 20, 2006; and

(2) For Model 757-300 series airplanes: Boeing Special Attention Service Bulletin 757-24-0106, Revision 2, dated April 20, 2006.

One-Time Inspections and Corrective Actions

(g) Within 24 months after the effective date of this AD, perform a general visual inspection for damage (including but not limited to chafing) of power feeder wire bundles W3312 and W3412 at front spar station 148.90 in the left and right wings, and a general visual inspection of the support clamps for those power feeder wire bundles to determine whether the clamps are properly installed, and, before further flight, do all applicable corrective actions. Do these actions by doing all of the applicable actions in the service bulletin.

Actions Accomplished Previously

(h) Inspections and corrective actions done before the effective date of this AD in accordance with the service information listed in Table 2 of this AD are acceptable for compliance with the corresponding actions required by this AD.

Table 2.—Other Acceptable Service Bulletin Revisions

Boeing Special Attention Service Bulletin	Revision level	Date
757-24-0105	Original	September 30, 2004.
757-24-0105	1	June 23, 2005.
757-24-0106	Original	September 30, 2004.
757-24-0106	1	June 23, 2005.

Special Flight Permit

(i) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished, provided that the generator served by the power feeder wire bundles specified in paragraph (g) of this AD is disconnected.

Alternative Methods of Compliance (AMOCs)

(j)(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) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on August 11, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.