Airworthiness directives: McDonnell Douglas,

[Federal Register: September 3, 1998 (Volume 63, Number 171)]

[Proposed Rules]

[Page 46934-46936]

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

[DOCID:fr03se98-31]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-71-AD]

RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model MD-11 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 MD-11 series airplanes. This proposal would require a one-time visual inspection to detect discrepancies of the seat tracks and adjacent structure underneath lavatories, and repair, if necessary. This proposal also would require installation of a non-metallic barrier on the bottom of each lavatory foot fitting, and replacement of existing seat track fittings with new seat track fittings. This proposal is prompted by reports of galvanic corrosion found on the seat tracks at attachment points under certain lavatories. The actions specified by the proposed AD are intended to prevent corrosion of seat tracks and adjacent structure. Corrosion of the seat tracks and adjacent structure could result in shifting of lavatories, which could lead to injury of passengers and crew, as well as damage to aircraft structure and systems.

DATES: Comments must be received by October 19, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-71-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 The Boeing Company, Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft

[[Page 46935]]

Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: David Hsu, Aerospace Engineer,Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5323; fax (562) 627-5210.

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 must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-71-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. 98-NM-71-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of occurrences on six McDonnell Douglas MD-11 series airplanes of galvanic corrosion of the seat tracks under certain lavatories. Investigation revealed that the corrosion developed at the attachment points between the seat tracks and lavatories. Further investigation has revealed that the design of the attachment system allows dissimilar metals to come in contact with each other, causing galvanic corrosion. In some cases, the corrosion caused the seat track attachments for the lavatory to become ineffective. This condition, if not corrected, could result in shifting of lavatories, which could lead to injury to passengers and crew, as well as damage to airplane structure and systems.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Service Bulletin MD11-53-043, Revision 02, dated May 28, 1996. This service bulletin describes procedures for installation of a non-metallic barrier on the bottom of each lavatory foot fitting, and replacement of existing seat track fittings with new seat track fittings. Accomplishment of the actions specified in the McDonnell Douglas service bulletin is intended to adequately address the identified unsafe condition. This service bulletin references JAMCO Service Bulletin MD11-25-1010, dated July 12, 1994, as an additional source of service information for accomplishment of the installation and replacement.

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 McDonnell Douglas service bulletin described previously. The actions are required to be accomplished in accordance with the service bulletin described previously, except as discussed below. The proposed AD also would require that operators perform a one-time visual inspection to detect discrepancies (i.e., corrosion and breakage) of the seat tracks and adjacent structure underneath the subject lavatories.

Differences Between Proposed Rule and Service Bulletin Information

Operators should note that the service bulletins do not provide information regarding a one-time visual inspection to detect discrepancies (i.e., corrosion and breakage) of the seat tracks and adjacent structure underneath lavatories. However, this proposal would require a one-time visual inspection of certain areas described in the JAMCO service bulletin, where lavatories are installed or were previously installed. Additionally, as the service bulletins do not provide inspection procedures they also do not provide repair procedures. However, this proposal would require that repair conditions be dispositioned prior further flight, in accordance with the McDonnell Douglas MD-11 Structural Repair Manual, or in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office. The FAA finds that this visual inspection to detect discrepancies (i.e., corrosion and breakage) is necessary, so that the corroded area is repaired prior to installation of new seat track fittings.

Cost Impact

There are approximately 143 airplanes of the affected design in the worldwide fleet. The FAA estimates that 46 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 40 work hours per airplane to accomplish the proposed inspection, installation, and replacement, and that the average labor rate is $60 per work hour. Required parts would cost less than $1,000 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be a maximum of $156,400, or $3,400 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 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.

[[Page 46936]]

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:

   McDonnell Douglas: Docket 98-NM-71-AD.

   Applicability: Model MD-11 series airplanes, as listed in McDonnell Douglas Service Bulletin MD-11-53-043, Revision 02, dated May 28, 1996; 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 detect and correct corrosion of seat tracks and adjacent structure, which could result in shifting of lavatories causing injury to passengers and crew, as well as damage to aircraft structure and systems, accomplish the following:

   (a) Within 15 months after the effective date of this AD, conduct a visual inspection to detect discrepancies (i.e., corrosion and breakage) of the seat tracks and adjacent structure at the lavatory locations defined in JAMCO Service Bulletin MD-11-25-1010, dated July 12, 1994.

   (1) If no discrepancy is detected, prior to further flight, install a non-metallic barrier on the bottom of each lavatory foot fitting and replace existing seat track fittings with new fittings, in accordance with McDonnell Douglas Service Bulletin MD-11-53-043, Revision 02, dated May 28, 1996.

   (2) If any discrepancy is detected, prior to further flight, repair in accordance with the McDonnell Douglas MD-11 Structural Repair Manual, or in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Prior to further flight following accomplishment of the repair, install a non-metallic barrier on the bottom of each lavatory foot fitting and replace existing seat track fittings with new fittings, in accordance with McDonnell Douglas Service Bulletin MD-11-53-043, Revision 02, dated May 28, 1996.

   (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, Los Angeles ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO.

   Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

   (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 August 28, 1998. Vi L. Lipski, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 98-23739Filed9-2-98; 8:45 am]

   BILLING CODE 4910-13-U