Airworthiness directives: McDonnell Douglas,

[Federal Register: February 22, 1999 (Volume 64, Number 34)]

[Proposed Rules]

[Page 8530-8532]

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

[DOCID:fr22fe99-17]

Proposed Rules Federal Register

This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules.

[[Page 8530]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-05-AD]

RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series Airplanes and Model MD-88 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 McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes. This proposal would require a one-time visual inspection to determine whether self-aligning nuts are installed at certain locations of the aft pressure bulkhead tee; and corrective actions, if necessary. This proposal is prompted by reports of failures of certain Hi-Lok pin fasteners of the aft pressure bulkhead tee due to installation of non-self-aligning nuts. The actions specified by the proposed AD are intended to prevent failure of certain Hi-Lok pin fasteners and subsequent gouging of the aft pressure bulkhead tee, which could result in fatigue cracking and reduced structural integrity of the airplane.

DATES: Comments must be received by April 8, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-05-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 Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Carl Fountain, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5222; 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 99-NM-05-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-05-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of failures of certain Hi-Lok pin fasteners of the aft pressure bulkhead tee on certain McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes. These failed Hi-Lok pin fasteners were found during the first 10,000-flight-hour special surveillance inspection. The failures are attributed to the installation of non-self-aligning nuts. Investigation revealed that, certain Hi-Lok pins were installed through a tapered surface on the pressure bulkhead tee, and were attached to fasteners without self- aligning nuts. The nuts became loose and allowed the pins to gouge the aft pressure bulkhead tee. Loose or failed fasteners and subsequent gouging, if not detected and corrected, could result in fatigue cracking and reduced structural integrity of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Service Bulletin MD80-53-201, Revision 02, dated July 20, 1998, which describes procedures for a one-time visual inspection to determine whether self- aligning nuts are installed at certain locations of the aft pressure bulkhead tee; and corrective actions, if necessary. The corrective actions involve removal of any non-self-aligning nut; a visual inspection to detect gouges in the aft pressure bulkhead tee; repair of any gouges that are found to be within the specified limits; and installation of new self-aligning nuts. 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

[[Page 8531]]

described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that the service bulletin recommends that the inspection to determine whether self-aligning nuts are installed be performed at the operator's earliest practical maintenance period, and that certain non-self-aligning nuts be replaced when the engines have been removed for maintenance. However, the FAA has determined that such interpretive compliance times would not address the identified unsafe condition in a timely manner. In developing appropriate compliance times for this proposed 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, the accessibility of the area to be replaced, and the time necessary to accomplish the replacement (approximately 8 hours). In light of all of these factors, the FAA finds that inspecting for non-self-aligning nuts within a 24-month compliance time and replacing any non self-aligning nut prior to further flight; to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Operators also should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain gouging repair conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

Cost Impact

There are approximately 1,042 airplanes of the affected design in the worldwide fleet. The FAA estimates that 695 airplanes of U.S. registry would be affected by this proposed AD, and that it would take approximately 1 work hour per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed inspection by this AD on U.S. operators is estimated to be $41,700, 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 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: McDonnell Douglas: Docket 99-NM-05-AD.

   Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88 airplanes; as listed in McDonnell Douglas Service Bulletin MD80-53- 201, Revision 02, dated July 20, 1998; 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 failure of certain Hi-Lok pin fasteners and subsequent gouging of the aft pressure bulkhead tee, which could result in fatigue cracking and reduced structural integrity of the airplane, accomplish the following:

   (a) Within 24 months after the effective date of this AD, perform a one-time visual inspection to determine whether self- aligning nuts are installed at certain locations of the aft pressure bulkhead tee, in accordance with McDonnell Douglas Service Bulletin MD80-53-201, Revision 02, dated July 20, 1998.

   (1) If all nuts installed are self-aligning, no further action is required by this AD.

   (2) If any nut is determined to be non-self-aligning, prior to further flight, remove the existing nut and perform a one-time visual inspection to detect gouges in the aft pressure bulkhead tee on station Y=1338.000, in accordance with the service bulletin.

   (i) If no gouge is detected, prior to further flight, install new self-aligning nuts in accordance with the service bulletin.

   (ii) If any gouge is detected that is within the repair limits specified in the service bulletin, prior to further flight, repair the gouge and install new self-aligning nuts in accordance with the service bulletin.

   (iii) If any gouge is detected that is outside the repair limits specified in the service bulletin, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

   Note 2: Inspections, repairs, or replacements that have been accomplished prior to the effective date of this AD, in accordance with McDonnell Douglas Service Bulletin MD80-53-201, dated July 6, 1988, or Revision 1, dated March 22, 1991, are considered acceptable for compliance with the applicable action specified by this AD.

   (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 3: 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.

   [[Page 8532]]

   Issued in Renton, Washington, on February 12, 1999. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-4216Filed2-19-99; 8:45 am]

   BILLING CODE 4910-13-U