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 supersedure of an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes, that currently requires replacement of the air driven generator (ADG) wire assembly with a new, increased length wire assembly. This action would require, among other actions, replacement of the existing ADG wire assembly in the right air conditioning compartment with a certain new wire assembly. This action also would expand the applicability of the existing AD to include additional airplanes. This proposal is prompted by an investigation that revealed the length of the new wire assembly is too long and causes the assembly to chafe against the left emergency alternating current bus of the ADG. The actions specified by the proposed AD are intended to prevent loss of the charging capability of the airplane battery due to chafing. Loss of the charging capability of the airplane battery, coupled with a loss of all normal electrical power, could prevent continued safe flight and landing of the airplane.

DATES:

Comments must be received by April 6, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-193-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 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-193-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 the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Brett Portwood, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5350; 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 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-193-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-193-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On February 10, 2000, the FAA issued AD 2000-03-12, amendment 39-11571 (65 FR 8030, February 17, 2000), applicable to certain McDonnell Douglas Model MD-11 series airplanes, to require replacement of the air driven generator (ADG) wire assembly with a new, increased length wire assembly. That action was prompted by a report of loose terminal attachment hardware on the ADG power monitor relay due to a stress condition on the terminal attachment points. The requirements of that AD are intended to prevent loss of the charging capability of the airplane battery. Loss of the charging capability of the airplane battery, coupled with a loss of all normal electrical power, could prevent continued safe flight and landing of the airplane.

The incident that prompted AD 2000-03-12 is not considered to be related to an accident that occurred off the coast of Nova Scotia involving a McDonnell Douglas Model MD-11 series airplane. The cause of that accident is still under investigation.

Other Related Rulemaking

The FAA, in conjunction with Boeing and operators of Model MD-11 series airplanes, is continuing to review all aspects of the service history of those airplanes to identify potential unsafe conditions and to take appropriate corrective actions. This proposed AD is one of a series of actions identified during that process. The process is continuing and the FAA may consider additional rulemaking actions as further results of the review become available.

Actions Since Issuance of Previous Rule

Since the issuance of AD 2000-03-12, an investigation revealed that the length of the new wire assembly installed per that AD is too long and causes the assembly to chafe against the left emergency alternating current bus of the airplane battery. This condition, if not corrected, could result in the loss of the charging capability of the ADG, which, when coupled with a loss of all normal electrical power, could consequently prevent continued safe flight and landing of the airplane.

In addition, Model MD-11 series airplanes, manufacturer's fuselage numbers 0633 through 0646, inclusive, which were not subject to the requirements of AD 2000-03-12, had a modification accomplished in production that is similar to the replacement required by AD 2000-03-12. Therefore, the FAA finds that these additional airplanes are also subject to the identified unsafe condition.

Also, the original issue and Revision 01 of Boeing (McDonnell Douglas) Service Bulletin MD11-24-128 (which were referenced in AD 2000-03-12 as the appropriate sources of service information for accomplishing the required actions) contained an error, which resulted in the misidentification of a wire assembly and the omission of an existing wire on an illustration.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin MD11-24-128, Revision 02, dated October 31, 2000, which describes procedures for replacement of the existing ADG wire assembly located on the transformer panel at station Y=568.333 in the right air conditioning compartment with a certain new wire assembly. The service bulletin also describes procedures for replacing the associated clamps and screws of the ADG wire assembly with new clamps and screws, and torque tightening the terminal hardware to certain limits. 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 supersede AD 2000-03-12 to require accomplishment of the actions specified in the service bulletin described previously.

Cost Impact

There are approximately 191 Model MD-11 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 60 airplanes of U.S. registry would be affected by this proposed AD.

The new actions that are proposed in this AD action would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $810 per airplane. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $52,200, or $870 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the current or proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this 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.

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.