Airworthiness directives: Boeing,

[Federal Register: October 27, 1999 (Volume 64, Number 207)]

[Proposed Rules]

[Page 57794-57796]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr27oc99-14]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-232-AD]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 777 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 777 series airplanes. This proposal would require replacement of the clevis ends on the tie rods for the center stowage bin supports with improved clevis ends. This proposal is prompted by a report that, under ultimate load conditions, the aluminum clevis ends on the tie rods for the center stowage bin supports can break. The actions specified by the proposed AD are intended to prevent broken tie rods, which could result in the center stowage bins dropping onto the passenger seats below, causing possible injury to the occupants.

DATES: Comments must be received by December 13, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-232-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.

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: Julie Alger, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue S.W., Renton, Washington 98055-4056; telephone (425) 227-2779; 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 notice may be changed in light of the comments received.

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 filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice

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must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NM-232-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. 99-NM-232-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report from Boeing indicating that, under ultimate load conditions on certain Boeing Model 777 series airplanes, the aluminum clevis ends on the tie rods that attach the center stowage bin support structure to the airplane structure can break. Such breakage has been attributed to the material of which the clevis ends are made (aluminum). This condition, if not corrected, could result in misalignment of the center stowage bins. Multiple broken tie rods could allow the center stowage bins to drop onto the passenger seats below, causing possible injury to the occupants.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 777-25- 0120, dated February 11, 1999, which describes procedures for replacement of the aluminum clevis ends on affected tie rods (81 locations on 777-200 airplanes, 115 locations on 777-300 airplanes) with new steel clevis ends. The steel clevis ends are stronger than the aluminum clevis ends and will not break under ultimate load conditions. Accomplishment of the actions specified in the 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 service bulletin described previously.

Cost Impact

There are approximately 184 airplanes (168 Model 777-200 and 16 Model 777-300) of the affected design in the worldwide fleet. The FAA estimates that 41 airplanes of U.S. registry, all Model 777-200 airplanes, would be affected by this proposed AD, and that it would take approximately 12 work hours per airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost approximately $15,938 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $682,978, or $16,658 per airplane.

Currently, there are no Model 777-300 airplanes on the U.S. Register that would be affected by this AD. However, should an unmodified airplane be imported and placed on the U.S. Register in the future, it would take approximately 17 work hours per airplane to accomplish the actions proposed by this AD, at an average labor rate of $60 per work hour. Required parts would cost approximately $18,457 per airplane. Based on these figures, the cost impact of the proposed AD on these airplanes is estimated to be $19,477 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 AD were not adopted.

Regulatory Impact

The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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.

   Sec. 39.13 [Amended]

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

   Boeing: Docket 99-NM-232-AD.

   Applicability: Model 777 series airplanes, line numbers 2 through 103 inclusive, 105 through 119 inclusive, and 121 through 187 inclusive; 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 broken tie rods, which could result in the center stowage bins dropping onto the passenger seats below, causing possible injury to the occupants, accomplish the following:

   (a) Within 4 years after the effective date of this AD, replace the aluminum clevis ends on the tie rods for the center stowage bin supports with new steel clevis ends, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 777-25-0120, dated February 11, 1999.

   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, Transport Airplane Directorate. 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.

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   Special Flight Permits

   (c) Special flight permits may be issued in accordance with Secs. 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 October 21, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-28076Filed10-26-99; 8:45 am]

   BILLING CODE 4910-13-U