01-21229. Airworthiness Directives; Boeing Model 757 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 series airplanes. This proposal would require a one-time inspection of a wire bundle in the front left wing spar for chafing and for proper installation of a Teflon sleeve; corrective action, if necessary; and installation of extra protection against chafing. This action is necessary to prevent chafing between the wire bundle and the front left wing spar, which could result in electrical arcing and subsequent ignition of flammable vapors and possible uncontrollable fire. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 9, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-07-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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-07-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:

John Vann, Aerospace Engineer, Propulsion Branch, ANM-140S, 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-07-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-07-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received several reports of chafed fuel shutoff valve wires and densitometer wires in the wire bundle, part number (P/N) W5100, at front spar station 318.99 on Boeing Model 757 series airplanes. The reports indicated that the wires were found to be chafing against the left wing spar on the lower chord. One operator advised that false illumination of the “L HYD PRESS” light had occurred in flight. Subsequent repair of the wires in the wire bundle, P/N W5100, eliminated the false indication light condition.

Based on these reports, the airplane manufacturer inspected installation in the left wing spar of the wire bundle, P/N W5100, of airplanes in production. This inspection revealed that a potential chafing condition exists between the lower chord and the wire bundle, P/N W5100, adjacent to front spar station 318.99. Subsequently, one operator found chafing of the noted wire bundle as a result of missing sleeving on the airplane. Additional inspections of production airplanes found a number of airplanes with inadequate sleeving installed.

The wing leading edge, where front spar station 318.99 is located, is classified as a flammable leakage zone, and, as such, does not have fire detection and extinguishing capability, but flammable vapors are likely to be present. Chafing of the wire bundle, P/N W5100, against the wing spar, if not corrected, could result in electrical arcing and subsequent ignition of flammable vapors, possibly leading to uncontrollable fire.

Explanation of Relevant Service Information

Boeing has issued Service Bulletins 757-29-0058 (for Model 757-200 series airplanes), and 757-29-0059 (for Model 757-300 series airplanes), both dated November 9, 2000. The service bulletins describe procedures for inspection of the wire bundle, P/N W5100, for chafing, and wire repair, if necessary; installation of a grommet; and inspection of the wire's teflon sleeving for proper installation and corrective action (including, but not limited to, repairing or adding sleeving if it does not exist, and ensuring that it is installed 1 inch past the upper clamp and 3 inches below the lower front spar chord), if necessary. Accomplishment of the actions specified in the applicable service bulletin 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 applicable service bulletin described previously. The proposed AD also would require that operators report results of inspection findings to the FAA.

Cost Impact

There are approximately 1,058 airplanes of the affected design in the worldwide fleet. The FAA estimates that 615 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 actions, and that the average labor rate is $60 per work hour. The cost of required parts would be negligible. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $36,900, 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-07-AD.

Applicability: Model 757 series airplanes, certificated in any category, as listed in Boeing Service Bulletins 757-29-0058 and 757-29-0059, both dated November 9, 2000.

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 (c) 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 chafing between the wire bundle and the front left wing spar, which could result in electrical arcing and subsequent ignition of flammable vapors and possible uncontrollable fire, accomplish the following:

Compliance Time

(a) Within 6 months from the effective date of this AD, perform the actions specified in paragraphs (a)(1), (a)(2), and (a)(3) of this AD, in accordance with Boeing Service Bulletin 757-29-0058, dated November 9, 2000 (for Model 757-200 series airplanes); or Boeing Service Bulletin 757-29-0059, also dated November 9, 2000 (for Model 757-300 series airplanes); as applicable.

Inspection and Corrective Action

(1) Perform a detailed visual inspection of the wire bundle, part number (P/N) W5100, adjacent to front spar station 318.99 in the left wing leading edge, to detect chafing. If any damage is found, before further flight, repair the wire bundle.

Note 2:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Modification

(2) Install a caterpillar grommet to the edge of the spar lower chord in the left wing leading edge.

Inspection and Corrective Action

(3) Perform a general visual inspection for proper installation of perforated Teflon sleeving on the wire bundle, P/N W5100. If sleeving does not exist or is not covering the area from 1.0 inch beyond the clamp point to 3.0 inches below the spar flange edge, before further flight, install or repair the teflon sleeving.

Note 3:

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 under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, 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.”

Note 4:

An optional 0.5-inch spacer may be used in accordance with the applicable service bulletin above, Section 3, Accomplishment Instructions, Work Instructions, to prevent the wire bundle from contacting the lower chord of the front spar on the left wing.

Reporting

(b) If the Teflon sleeving is found missing or improperly installed during the inspection required in paragraph (a)(3) of this AD, submit a report of inspection findings to the Manager, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax [phone]; at the applicable time specified in paragraph (b)(1) or (b)(2) of this AD. The report must include the inspection results, a description of any discrepancies found, the airplane serial number, and the number of landings and flight hours on the airplane. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(1) For airplanes on which the inspection is accomplished after the effective date of this AD: Submit the report within 30 days after performing the inspection required by paragraph (a)(3) of this AD.

(2) For airplanes on which the inspection specified in paragraph (a)(3) has been accomplished prior to the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Alternative Methods of Compliance

(c) 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 5:

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

(d) Special flight permits may be issued in accordance with §§ 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 August 16, 2001.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.