03-13385. Airworthiness Directives; McDonnell Douglas Model MD-11 and -11F 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 MD-11 and -11F airplanes. This proposal would require a one-time inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, and follow-on and corrective actions if necessary. This action is necessary to prevent such corrosion, which could result in structural damage and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by July 14, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-06-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-06-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: Data and Service Management, Dept. C1-L5A (D800-0024). 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.

FOR FURTHER INFORMATION CONTACT:

Ron Atmur, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

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 2002-NM-06-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. 2002-NM-06-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports of water and subsequent corrosion in the barrel nut holes in the area where the outer sections attach to the center section on the left and right sides of the upper horizontal stabilizer on certain MD-11 and -11F airplanes. In one incident, the sealant installed in the barrel nut hole had raised partially out, and severe corrosion was found when the sealant was removed. In two other incidents, removal of the mylar tape and sealant showed that the barrel nut holes were filled with water; investigation revealed that condensation accumulated in the barrel nut holes during flight. Such conditions, if not corrected, could result in structural damage and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin MD11-55-023, including Appendix A and Evaluation Form, dated November 28, 2001, which describes procedures for a one-time inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, and follow-on and corrective actions. The follow-on and corrective actions include but are not limited to the following:

• Condition 1—If no corrosion is found, the service bulletin describes procedures to clean, seal, and tape the barrel nut holes per Figure 4 of the service bulletin;
• Condition 2—If corrosion is found that does not exceed the limits specified in Figure 2 of the service bulletin, the service bulletin describes procedures to remove and retain the barrel nuts and bolts, remove the corrosion, and seal and tape the affected barrel nut holes per Figure 2 of the service bulletin; or
• Condition 3—If corrosion is found that does not exceed 0.060 inch on the barrel nut bottom, the service bulletin describes procedures to remove and retain the barrel nuts and bolts, remove the corrosion, fabricate and install bushings, seal and tape the holes, and reinstall the barrel nuts and bolts per Figures 2 of the service bulletin. If corrosion is found in the barrel nut bearing area and/or corrosion exceeds the dimensional limits for each hole, the service bulletin specifies contacting the manufacturer for repair disposition.

The service bulletin also references the procedures in the MD-11 Airplane Maintenance Manual and the Structural Repair Manual for the accomplishment of certain follow-on actions.

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, except that the proposed AD would not require completing the Evaluation Form, and except as discussed below.

Differences Between This Proposed Rule and the Service Information

The service bulletin refers to a “visual” inspection. For the purposes of this AD, we have determined that the procedures in the service bulletin constitute a “detailed inspection.” Note 2 of this proposed AD defines such an inspection.

Although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repairs, this proposed AD would require such repairs to be accomplished per a method approved by the FAA.

Cost Impact

There are approximately 191 airplanes of the affected design in the worldwide fleet. The FAA estimates that 66 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 6 work hours 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 inspection proposed by this AD on U.S. operators is estimated to be $23,760, or $360 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 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.

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.

§ 39.13

[Amended]

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

McDonnell Douglas: Docket 2002-NM-06-AD.

Applicability: Model MD-11 and -11F airplanes, as listed in Boeing Service Bulletin MD11-55-023, dated November 28, 2001, 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 corrosion of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer, which could result in structural damage and consequent reduced controllability of the airplane, accomplish the following:

One-Time Inspection/ Follow-on and Corrective Actions

(a) Within 18 months or 6,000 flight hours after the effective date of this AD, whichever is later: Do a one-time detailed inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, per Boeing Service Bulletin MD11-55-023, including Appendix A, dated November 28, 2001, and excluding Evaluation Form. Before further flight, do the actions required by paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, as applicable.

Note 2:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(1) If no corrosion is found: Clean, seal, and tape the barrel nut holes per Figure 4 of the service bulletin.

(2) If corrosion is found that does not exceed the limits specified in Figure 2 of the service bulletin: Remove and retain the barrel nuts and bolts, remove the corrosion of the barrel nut hole, seal and tape the holes per Figure 4 of the service bulletin, and reinstall the barrel nuts and bolts per Figure 2 of the service bulletin.

(3) If corrosion is found that does not exceed 0.060 inch on the barrel nut bottom: Remove and retain the barrel nuts and bolts, remove the corrosion, fabricate and install bushings, seal and tape the holes per Figure 4 of the service bulletin, and reinstall the barrel nuts and bolts per Figure 2 of the service bulletin.

(4) If corrosion is found in the barrel nut bearing area, and/or corrosion exceeds the dimensional limits for each hole specified in Figure 2 of service bulletin: Repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA.

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, 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.

Special Flight Permit

(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 May 22, 2003.

Vi L. Lipski,

Manager, Transport Airplane Directorate, Aircraft Certification Service.