02-15106. Airworthiness Directives; Boeing Model 757-200, -200PF, -200CB, and -300 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes. This proposal would require inspection for damage of the W2800 wire bundle insulation, wire conductor, the wire bundle clamp bracket, and the BACC10GU( ) clamp, and repair or replacement with new or serviceable parts, if necessary. This proposal also would require installation of spacers between the clamp and the bracket. This action is necessary to prevent contact between the power feeder wires of the auxiliary power unit (APU) and the clamp bracket aft of the STA 1720 bulkhead due to chafing damage of the Adel clamp and “L” shaped bracket, which could result in electrical arcing and fire, or loss of electrical power in the airplane.

DATES:

Comments must be received by July 29, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-74-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-74-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Elias Nastiopoulos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-74-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-74-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report regarding a Boeing 757-200 series airplane indicating that, during a structural inspection of the generator power feeder (GPF) wires for the auxiliary power unit (APU), chafing damage was detected on the Adel clamp and the “L” shaped bracket. The clamp and bracket support the wires that are located just aft of the pressure seal fitting at the STA 1720 bulkhead. As a result of that finding, the operator that submitted the report inspected seven additional Model 757 series airplanes in its fleet for chafing damage. The report also indicated that the GPF wires of four of the seven airplanes had been either repaired or repositioned. Electrical contact between the power feeder wires of the APU and the clamp bracket aft of the STA 1720 bulkhead due to chafing damage of the Adel clamp and “L” shaped bracket, if not corrected, could result in electrical arcing and fire or loss of electrical power in the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 757-24-0089 (for Model 757-200 series airplanes) and Boeing Service Bulletin 757-24-0090 (for Model 757-300 series airplanes), both dated March 15, 2001. The service bulletins describe procedures for a general visual inspection for damage of the W2800 wire bundle insulation, wire conductor, the wire bundle clamp bracket, and the BACC10GU( ) clamp, and repair or replacement with new or serviceable parts, if necessary. The service bulletins also describe procedures for installing spacers between the clamp and the bracket and ensuring that there is 0.25-inch minimum clearance between the wire bundle and the aft edge of the bracket. Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletins described previously.

Similar Models

The installation of the GPF wires for the APU on certain Boeing Model 757-200PF series airplanes is similar to that installed on certain Boeing Model 757-200, -200CB, and certain Model 757-300 series airplanes. Therefore, all of these models may be subject to the same unsafe condition.

Cost Impact

There are approximately 934 Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 595 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed inspection and installation of spacers, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $35,700, or $60 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2001-NM-74-AD.

Applicability: Model 757-200, -200PF, -200CB, and -300 series airplanes, as listed in Boeing Service Bulletin 757-24-0089 and Boeing Service Bulletin 757-24-0090, both dated March 15, 2001, as applicable; certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent electrical contact between the power feeder wires of the auxiliary power unit (APU) and the clamp bracket aft of STA 1720 bulkhead due to chafing damage of the Adel clamp and “L” shaped bracket, which could result in electrical arcing and fire or loss of electrical power in the airplane; accomplish the following:

Inspection and Repair of Any Damage

(a) Within 15 months after the effective date of this AD, perform a general visual inspection for damage of the W2800 wire bundle insulation, wire conductor, the wire bundle clamp bracket, and the BACC10GU( ) clamp; per Boeing Service Bulletin 757-24-0089 (for Boeing Model 757-200 series airplanes) or Boeing Service Bulletin 757-24-0090 (for Boeing Model 757-300 series airplanes), both dated March 15, 2001, as applicable. If no damage is detected: Before further flight, install spacers and ensure that there is 0.25-inch minimum clearance between the wire bundle and aft edge of the bracket, per the applicable service bulletin.

(1) If any damage to the wire bundle insulation or the wire conductor is detected: Before further flight, repair the damage per the applicable service bulletin, install spacers, and ensure that there is 0.25-inch minimum clearance between the wire bundle and aft edge of the bracket; per the applicable service bulletin.

(2) If any damage to the wire bundle clamp bracket or the BACC10GU( ) clamp is detected: Before further flight, replace the clamp bracket and the clamp with new or serviceable parts, install spacers, and ensure that there is 0.25-inch minimum clearance between the wires bundle and aft edge of the bracket; per the applicable service bulletin.

Note 2:

For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed 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.”

Alternative Methods of Compliance

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(c) 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.

Issued in Renton, Washington, on June 7, 2002.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.