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Proposed Rule

Airworthiness Directives; McDonnell Douglas Model DC-10 Series Airplanes, Model MD-10 Series Airplanes, and Model MD-11 Series Airplanes

Document Details

Information about this document as published in the Federal Register.

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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-10 series airplanes, Model MD-10 series airplanes, and Model MD-11 series airplanes. This proposal would require repetitive inspections of the number 1 and 2 electric motors of the auxiliary hydraulic pump for electrical resistance, continuity, mechanical rotation, and associated wiring resistance/voltage; and corrective actions, if necessary. This action is necessary to prevent various failures of electric motors of the auxiliary hydraulic pump and associated wiring, which could result in fire at the auxiliary hydraulic pump and consequent damage to the adjacent electrical equipment and/or structure. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 11, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-269-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-269-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 Aircraft Group, Long Beach 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, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

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FOR FURTHER INFORMATION CONTACT:

Albert Lam, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone (562) 627-5346; fax (562) 627-5210.

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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-269-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-269-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports that, during ground operations or when powered in flight by the air driven generator, the electric motors of the auxiliary hydraulic pump and associated motor feeder cables failed on certain McDonnell Douglas Model MD-80, DC-10, MD-10, MD-11, and MD-90-30 series airplanes. These failures consisted of seized or difficult to turn rotor on the pump assembly, burnt and shorted motor feeder cables, and/or uncontained internal electric arcing failures with the electric motor. Investigation revealed that these failures may be caused by hydraulic fluid contamination to the electric motor portion of the pump, failed rotor bearing, and/or degradation of the stator's encapsulate material. These conditions, if not corrected, could result in a fire at the auxiliary hydraulic pump and consequent damage to the adjacent electrical equipment and/or structure.

Other Relevant Rulemaking

This proposed AD affects McDonnell Douglas Model DC-10, MD-10, and MD-11 series airplanes. The FAA is planning to issue a separate rulemaking Start Printed Page 70672action for McDonnell Douglas Model DC-9-81,-9-82, -9-83, and -9-87 series airplanes (i.e., MD-80 series airplanes); Model MD-88 airplanes; and Model MD-90-30 series airplanes to address the identified unsafe condition.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Alert Service Bulletin DC10-29A142, Revision 01, dated October 21, 1999 (for Model DC-10 and MD-10 series airplanes); and McDonnell Douglas Alert Service Bulletin MD11-29A057, Revision 01, dated October 21, 1999 (for Model MD-11 series airplanes). These service bulletins describe procedures for repetitive inspections of the number 1 and 2 electric motors of the auxiliary hydraulic pump for electrical resistance, continuity, mechanical rotation, and associated wiring resistance/voltage; and corrective actions, if necessary.

The corrective actions involve replacing the auxiliary hydraulic pump with a serviceable pump, troubleshooting, and repairing the wiring.

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.

Differences Between the Proposed AD and One of the Referenced Service Bulletins

On May 9, 2000, the FAA issued a Type Certificate (TC) for McDonnell Douglas Model MD-10-10F and MD-10-30F series airplanes. Model MD-10 series airplanes are Model DC-10 series airplanes that have been modified with an Advanced cockpit. The auxiliary hydraulic systems installed on Model MD-10-10F and MD-10-30F series airplanes (before or after the modifications necessary to meet the type design of a Model MD-10 series airplane) are identical to those auxiliary hydraulic systems on Model DC-10 series airplanes listed in the effectivity listing of McDonnell Douglas Alert Service Bulletin DC10-29A142. Therefore, all of these airplanes may be subject to the same unsafe condition. In addition, the manufacturer's fuselage number and factory serial number are not changed during the conversion from a Model DC-10 to Model MD-10. The FAA finds that Model MD-10-10F and MD-10-30F series airplanes were not specifically identified by model in the effectivity listing of the subject service bulletin; however, they were identified by manufacturer's fuselage numbers. Therefore, the FAA has included Model MD-10-10F and MD-10-30F series airplanes in the applicability of the proposed AD.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Cost Impact

There are approximately 604 Model DC-10, MD-10, and MD-11 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 396 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $23,760, or $60 per airplane, per inspection cycle.

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.

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.

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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:

McDonnell Douglas: Docket 2000-NM-269-AD.

Applicability: Model DC-10 and MD-10 series airplanes, as listed in McDonnell Douglas Alert Service Bulletin DC10-29A142, Revision 01, dated October 21, 1999; and Model MD-11 series airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD11-29A057, Revision 01, dated October 21, 1999; 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 (e) 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 various failures of electric motors of the auxiliary hydraulic pump and associated wiring, which could result in fire at the auxiliary hydraulic pump and consequent damage to the adjacent electrical equipment and/or structure, accomplish the following:

Inspection

(a) Do a detailed inspection of the number 1 and 2 electric motors of the auxiliary hydraulic pump for electrical resistance, continuity, mechanical rotation, and Start Printed Page 70673associated wiring resistance/voltage, per McDonnell Douglas Alert Service Bulletin DC10-29A142, Revision 01, dated October 21, 1999 (for Model DC-10 and MD-10 series airplanes); or McDonnell Douglas Alert Service Bulletin MD11-29A057, Revision 01, dated October 21, 1999 (for Model MD-11 series airplanes); as applicable; at the applicable time specified in paragraph (a)(1) or (a)(2) of this AD.

(1) For Model DC-10 and MD-10 series airplanes: Inspect within 6 months after the effective date of this AD.

(2) For Model MD-11 series airplanes that have accumulated 3,000 flight hours or more as of the effective date of this AD: Inspect within 6 months after the effective date of this AD.

(3) For Model MD-11 series airplanes that have accumulated less than 3,000 flight hours as of the effective date of this AD: Inspect within 6 months after accumulating 3,000 flight hours.

Condition 1, No Failures: Repetitive Inspections

(b) If no failures are detected during the inspection required by paragraph (a) of this AD, repeat the inspection required by paragraph (a) of this AD every 5,000 flight hours.

Condition 2, Failure of Any Pump Motor: Replacement and Repetitive Inspections

(c) If any pump motor fails during any inspection required by paragraph (a) of this AD, before further flight, replace the auxiliary hydraulic pump with a serviceable pump, per McDonnell Douglas Alert Service Bulletin DC10-29A142, Revision 01, dated October 21, 1999 (for Model DC-10 and MD-10 series airplanes); or McDonnell Douglas Alert Service Bulletin MD11-29A057, Revision 01, dated October 21, 1999 (for Model MD-11 series airplanes); as applicable. Repeat the inspection required by paragraph (a) of this AD every 5,000 flight hours.

Condition 3, Failure of Any Wiring: Repair and Repetitive Inspections

(d) If any wiring fails during any inspection required by paragraph (a) of this AD, before further flight, troubleshoot and repair the wiring, per McDonnell Douglas Alert Service Bulletin DC10-29A142, Revision 01, dated October 21, 1999 (for Model DC-10 and MD-10 series airplanes); or McDonnell Douglas Alert Service Bulletin MD11-29A057, Revision 01, dated October 21, 1999 (for Model MD-11 series airplanes); as applicable. Repeat the inspection required by paragraph (a) of this AD every 5,000 flight hours.

Alternative Methods of Compliance

(e) 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 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, 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.

Special Flight Permit

(f) 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 November 20, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 00-30121 Filed 11-24-00; 8:45 am]

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