Airworthiness Directives; Boeing Model 737-300, 737-400, 737-500, 737-600, 737-700, 737-800, 757-200, 757-200PF, 757-200CB, and 757-300 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 would apply to certain Boeing Model 737-300, 737-400, 737-500, 737-600, 737-700, 737-800, 757-200, 757-200PF, 757-200CB, and 757-300 series airplanes. This proposal would require a test of the two electrical circuits that close the fuel shutoff valve on the wing spar, and repair, if necessary. This action is necessary to prevent inability to shut off the flow of fuel to an engine after an uncontained engine failure, which could result in a fire spreading to other parts of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by February 12, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-308-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-308-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:

Kathrine Rask, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1547; fax (425) 227-1181.

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 2000-NM-308-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. 2000-NM-308-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report indicating that the functional test performed during production of certain Boeing Model 737-300, 737-400, 737-500, 737-600, 737-700, 737-800, 757-200, 757-200PF, 757-200CB, and 757-300 series airplanes is not adequate to ensure that two electrical circuits that close the fuel shutoff valve on the wing spar can both supply electrical power to the fuel shutoff valve. Investigation revealed three airplanes in service that had wiring problems. The functional test only verifies that the fuel shutoff valve operates correctly, and only one of the two circuits needs to supply power for the fuel shutoff valve to operate correctly. The design incorporates two separate electrical circuits that close the fuel shutoff valve to ensure that, if one circuit is severed by debris from an uncontained engine failure, one circuit will still be available so that fuel can be shut off from the failed engine. However, if only one of the two electrical circuits that close the fuel shutoff valve is supplying power, and it is severed as a result of an uncontained engine failure, the flight crew will be unable to shut off the flow of fuel to the failed engine. This condition, if not corrected, could result in a fire spreading to other parts of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Special Attention Service Bulletin 737-28-1164, dated August 24, 2000, which applies to certain Boeing Model 737-300, 737-400, and 737-500 series airplanes. That service bulletin describes a one-time test of the two electrical circuits that close the fuel shutoff valve on each wing spar to determine if there is continuity. The service bulletin also notes what procedures to use to locate and repair any discontinuity.

The FAA has also reviewed and approved the following service bulletins, all dated October 26, 2000:

• Boeing Special Attention Service Bulletin 737-28-1160, Revision 1 (which applies to certain Boeing Model 737-600, 737-700, and 737-800 series airplanes).
• Boeing Special Attention Service Bulletin 757-28-0060, Revision 1 (which applies to certain Boeing Model 757-200, 757-200PF, and 757-200CB series airplanes).
• Boeing Special Attention Service Bulletin 757-28-0061, Revision 1 (which applies to certain Boeing Model 757-300 series airplanes).

These service bulletins describe procedures for a one-time test to measure the voltage of the two electrical circuits that close the fuel shutoff valve on the wing spar, and specify appropriate procedures to be used if inappropriate voltage is found.

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.

Cost Impact

There are approximately 3,403 airplanes of the affected design in the worldwide fleet.

The FAA estimates that this proposed AD would affect 795 Model 737-300, -400, and -500 airplanes of U.S. registry. The proposed test would take approximately 1 work hour on each of these airplanes, at an average labor rate of $60 per work hour. Based on these figures, the FAA estimates the cost impact of the proposed AD on U.S. operators of these airplanes to be $47,700, or $60 per airplane.

The FAA estimates that this proposed AD would affect 820 Model 737-600, 737-700, 737-800, 757-200, 757-200PF, 757-200CB, and 757-300 airplanes of U.S. registry. The proposed test would take approximately 3 work hours on each of these airplanes, at an average labor rate of $60 per work hour. Based on these figures, the FAA estimates the cost impact of the proposed AD on U.S. operators of these airplanes to be $147,600, or $180 per airplane.

The cost impact figures discussed above are 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.