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Proposed Rule

Airworthiness Directives; Boeing Model 737, 747, and 777 Series Airplanes

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Information about this document as published in the Federal Register.

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Start Preamble Start Printed Page 80794

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 737, 747, and 777 series airplanes. This proposal would require replacement of the seat track fittings on all passenger seats with new, improved fittings. This action is necessary to prevent unrestrained movement of the passenger seats during high forward deceleration of the airplane, which could result in injury to the passengers or crew members during an emergency landing. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by February 5, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-156-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-156-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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Jan Risheim, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-1675; fax (425) 227-1181.

End Further Info End Preamble Start Supplemental Information

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-156-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-156-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports from the manufacturer indicating that, on certain Model 737, 747, and 777 series airplanes, the shear plunger screws of certain seat track fittings broke during installation. Analysis of the broken screws revealed that various modifications had weakened the shear plunger screws. Further analysis revealed that high torque during seat installation resulted in broken shear plunger screws and subsequent disengagement of the shear plunger from the seat track. This condition, if not corrected, could result in unrestrained movement of the passenger seats during high forward deceleration of the airplane, and possible injury to the passengers or crew members during an emergency landing.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletins 737-25-1371, Revision 2, dated December 9, 1999 (for Model 737 series airplanes); 747-25-3196, Revision 1, dated May 13, 1999 (for Model 747 series airplanes); and 777-25-0111, Revision 1, dated May 13, 1999 (for Model 777 series airplanes). These service bulletins describe procedures for a one-time examination (inspection) to detect damaged or broken seat track fittings of the passenger seats, and replacement of the seat track fittings with serviceable or new, improved fittings. Boeing Service Bulletin 737-25-1407, dated December 9, 1999, describes procedures for replacement of the seat track fittings of the passenger seats with new, improved fittings. Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. Start Printed Page 80795

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, except as discussed below.

Differences Between Service Bulletins and This Proposed AD

Operators should note that, although the service bulletins specify replacement of the seat track fittings as soon as manpower, facilities and materials are available, the FAA has determined that an 18-month compliance for replacement of the seat track fittings would address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the replacement. In light of all of these factors, the FAA finds an 18-month compliance time for completion of the replacement to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

For certain airplanes, certain service bulletins provide for inspection and replacement of certain fittings with serviceable fittings if discrepancies are detected, then at a later date replacement with new, improved fittings. This proposed AD would mandate replacement of all seat track fittings on all the passenger seats of all affected airplanes with new, improved fittings. The FAA has determined that, due to the probability of defective shear plunger screws of the seat track fittings developing over time, mandating this replacement is necessary in order to maintain fleet safety.

Cost Impact

There are approximately 46 Model 737, 747, and 777 series airplanes of the affected design in the worldwide fleet.

For Model 737 series airplanes (2 U.S.-registered airplanes): It would take approximately 10 work hours per airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost approximately $15,100 per airplane. Based on these figures, the cost impact of the replacement proposed by this AD on U.S. operators is estimated to be $31,400, or $15,700 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.

Currently, there are no affected Model 747 series airplanes on the U.S. Register. However, should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 29 work hours to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost approximately $43,000. Based on these figures, the cost impact of the replacement proposed by this AD would be $44,740 per airplane.

Currently, there are no affected Model 777 series airplanes on the U.S. Register. However, should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 24 work hours to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost approximately $36,400. Based on these figures, the cost impact of the replacement proposed by this AD would be $37,840 per airplane.

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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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

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[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2000-NM-156-AD.

Applicability: Model 737, 747, and 777 series airplanes; certificated in any category; as specified in the Boeing service bulletins listed below:

For Model 737 series airplanes: 737-25-1371, Revision 2, dated December 9, 1999;

For Model 737 series airplanes: 737-25-1407, dated December 9, 1999;

For Model 747 series airplanes: 747-25-3196, Revision 1, dated May 13, 1999; or For Model 777 series airplanes: 777-25-0111, Revision 1, dated May 13, 1999.

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 unrestrained movement of the passenger seats during high forward deceleration of the airplane, which could result in injury to the passengers or crew members during an emergency landing, accomplish the following:

Replacement

(a) Within 18 months after the effective date of this AD: Replace all the seat track fittings on all the passenger seats with new, improved fittings, in accordance with the Start Printed Page 80796Accomplishment Instructions specified in Boeing Service Bulletin 737-25-1371 or 737-25-1407, both dated December 9, 1999 (for Model 737 series airplanes); Boeing Service Bulletin 747-25-3196, Revision 1, dated May 13, 1999 (for Model 747 series airplanes), or Boeing Service Bulletin 777-25-0111, Revision 1, dated May 13, 1999 (for Model 777 series airplanes); as applicable.

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 2:

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

Special Flight Permit

(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.

Start Signature

Issued in Renton, Washington, on December 18, 2000.

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 00-32764 Filed 12-21-00; 8:45 am]

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