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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-396-AD] 
          - RIN 2120-AA64 

# 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 DC-10-10, -15, -30, -30F (KC-10A military), and -40 series airplanes, and Model MD-10-10F and MD-10-30F series airplanes, that currently requires, among other actions, performing repetitive ultrasonic inspections of the attaching bolts on the inboard and outboard support on the inboard and outboard flap assembly to detect failed bolts, or verifying the torque of the attaching bolts on the inboard support on the outboard flap; and follow-on actions. This action, among other actions, would add a requirement to verify the torque of the attaching bolts on the outboard support on the inboard and outboard flaps, and allow repetitive torque verifications. This proposal is prompted by a review that revealed inadvertent omission of a requirement. The actions specified by the proposed AD are intended to prevent in-flight loss of inboard and outboard flap assemblies due to failure of H-11 attaching bolts, which could result in reduced controllability of the airplane. 

# DATES:

Comments must be received by April 9, 2001. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-396-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-396-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. 

# 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 (562) 627-5224; 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-396-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-396-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

                    On August 10, 2000, the FAA issued AD 2000-16-10, amendment 39-11866 (65 FR 50621, August 21, 2000), applicable to certain McDonnell Douglas Model DC-10-10, -15, -30, -30F (KC-10A military), and -40 series airplanes, and Model MD-10-10F and MD-10-30F series airplanes, to require performing repetitive ultrasonic inspections of the attaching bolts on the inboard and outboard support on the inboard and outboard flap assembly to detect failed bolts, or verifying the torque of the attaching bolts on the inboard support on the outboard flap; and follow-on actions. That AD also requires replacing all bolts with bolts made from Inconel, which constitutes terminating action for the repetitive inspection requirements. That action was prompted by an in-flight loss of the inboard flap assembly on an airplane during approach for landing. The requirements of that AD are intended to prevent in-flight loss of inboard and outboard flap assemblies due to failure of H-11 attaching bolts, which could                           ( print page 10971)                        result in reduced controllability of the airplane.                 

## Actions Since Issuance of Previous Rule 

Since the issuance of that AD, the FAA has reviewed the requirements of AD 2000-16-10 and found that we inadvertently omitted a requirement to verify the torque of the attaching bolts on the outboard support on the inboard and outboard flaps. The procedures for this verification were identified in McDonnell Douglas Alert Service Bulletin DC10-57A143, dated December 20, 1999, which was referenced in AD 2000-16-10 as the appropriate source of service information for accomplishing the requirements of that AD. Also, we inadvertently included a requirement to perform an ultrasonic inspection of the attaching bolts on the inboard support on the inboard flap assembly; this area is not subject to the identified unsafe condition. In addition, under certain conditions, that AD only requires repetitive ultrasonic inspections, rather than repetitive torque verifications or ultrasonic inspections, as indicated in the referenced service bulletin. In light of these findings, we find that AD 2000-16-10 needs to be superseded to correct these inaccuracies and adequately address the identified unsafe condition (i.e., failure of H-11 attaching bolts could result in an in-flight loss of inboard and outboard flap assemblies, and consequent reduced controllability of the airplane). 

## 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 2000-16-10 to continue to require repetitive ultrasonic inspections of the attaching bolts on the inboard and outboard support on the outboard flap assembly and on the outboard support on the inboard flap assembly to detect failed bolts, or verifying the torque of the attaching bolts on the inboard support on the outboard flap; and follow-on actions. The proposed AD also would continue to require replacing all bolts with bolts made from Inconel, which would constitute terminating action for the repetitive inspection requirements. Also, the proposed AD would add a requirement to verify the torque of the attaching bolts on the outboard support on the inboard and outboard flaps, and allow repetitive torque verification in lieu of the repetitive ultrasonic inspections. The actions would be required to be accomplished per McDonnell Douglas Alert Service Bulletin DC10-57A143, dated December 20, 1999. 

## Cost Impact 

There are approximately 412 Model McDonnell Douglas Model DC-10-10, -15, -30, -30F (KC-10A military), and -40 series airplanes, and Model MD-10-10F and MD-10-30F series airplanes of the affected design in the worldwide fleet. The FAA estimates that 244 airplanes of U.S. registry would be affected by this proposed AD. 

The inspection/torque verification that is currently required by AD 2000-16-10, and retained in this proposed AD, takes approximately between 2 and 8 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be between $29,280 and $117,120, or between $120 and $480 per airplane, per inspection cycle. 

The bolt replacement that is currently required by AD 2000-16-10, and retained in this proposed AD, takes approximately 288 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $2,987 per airplane. Based on these figures, the cost impact of the currently required replacement on U.S. operators is estimated to be $4,945,148, or $20,267 per airplane. 

The cost impact of the new torque verification proposed in this AD is included in the cost estimate above for the inspection/torque verification. 

The cost impact figures discussed above are 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. 

§ 39.13 

2. Section 39.13 is amended by removing amendment 39-11866 (65 FR 50621, August 21, 2000), and by adding a new airworthiness directive (AD), to read as follows:

**McDonnell Douglas:**                                 Docket 2000-NM-396-AD. Supersedes AD 2000-16-10, Amendment 39-11866.                            

*Applicability:*                                 Model DC-10-10, -15, -30, -30F (KC-10A military), and -40 series airplanes; and Model MD-10-10F and MD-10-30F series airplanes; as listed in McDonnell Douglas Alert Service Bulletin DC10-57A143, dated December 20, 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)(1) 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                                           ( print page 10972)                                        been eliminated, the request should include specific proposed actions to address it.                                

*Compliance:*                                 Required as indicated, unless accomplished previously.                             

To prevent in-flight loss of inboard and outboard flap assemblies due to failure of H-11 attaching bolts, which could result in reduced controllability of the airplane, accomplish the following: 

## Inspection or Torque Verification, and Corrective Actions, if Necessary 

(a) Within 2 months after September 25, 2000, (the effective date of AD 2000-16-10, amendment 39-11866), do an ultrasonic inspection of the attaching bolts on the inboard and outboard support on the outboard flap assembly and on the outboard support on the inboard flap assembly to detect failed bolts, or verify the torque of the attaching bolts on the inboard support on the outboard flap, per McDonnell Douglas Alert Service Bulletin DC10-57A143, dated December 20, 1999. 

(1) If no failed bolt is found, repeat the ultrasonic inspection or torque verification every 6 months. 

(2) If any failed bolt is found, before further flight, replace the bolt and associated parts with a new Inconel bolt and new associated parts per the service bulletin, except as provided by paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. Accomplishment of the replacement constitutes terminating action for the repetitive requirements of paragraph (a)(1) of this AD for that bolt. 

(i) If an Inconel bolt is not available for accomplishment of the replacement, replacement with a new H-11 steel bolt is acceptable provided that operators repeat the ultrasonic inspection or torque verification every 6 months until the requirements of paragraph (c) of this AD are accomplished. 

(ii) If a PLI washer is not available for accomplishment of the Inconel replacement, a new Inconel bolt can be temporarily installed without a new PLI washer provided that the bolt is torqued to the applicable value specified in the service bulletin. 

Within 6,000 flight hours after an Inconel bolt is torqued, replace the PLI washer with a new washer per the service bulletin. 

## Torque Verification 

(b) For airplanes on which the verification of the torque of the attaching bolts on the inboard support on the outboard flap was done per paragraph (a) of this AD: Within 2 months after the effective date of this AD, verify the torque of the attaching bolts on the outboard support on the inboard and outboard flaps, per McDonnell Douglas Alert Service Bulletin DC10-57A143, dated December 20, 1999; and do the applicable action(s) specified in paragraph (a)(1) or (a)(2) of this AD. 

## Bolt Replacement 

(c) Within 2 years after accomplishing the initial inspection required by paragraph (a) of this AD or the torque verification required by paragraphs (a) and (b) of this AD, do the action specified in paragraph (a)(2) of this AD for all H-11 bolts. 

Accomplishment of the replacement of all H-11 bolts with Inconcel bolts constitutes terminating action for the requirements of this AD. 

## Spares 

(d) As of 2 years after the effective date of this AD, no person shall install, on any airplane, an H-11 steel bolt, part number 71658-8-44, 71658-7-44, 71658-7-54, 71658-7-56, 71658-7-29, 71658-9-31, 71658-9-34, 71658-9-38, 71658-9-41, 71658-10-41, 71658-7-26, 71658-7-27, or 71658-8-29, on the inboard or outboard flap assembly. 

## Alternative Methods of Compliance 

(e)(1) 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.

(2) Alternative methods of compliance, approved previously per AD 2000-16-10, amendment 39-11866, are considered to be approved as alternative methods of compliance with this AD. 

## Special Flight Permits 

(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. 

Issued in Renton, Washington, on February 13, 2001. 

Vi L. Lipski, 

Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 01-4221 Filed 2-20-01; 8:45 am] 

BILLING CODE 4910-13-U