02-21508. Airworthiness Directives; McDonnell Douglas Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F, DC-10-30F (KC10A and KDC-10), MD-10-10F, and MD-10-30F 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-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F, DC-10-30F (KC10A and KDC-10), MD-10-10F, and MD-10-30F airplanes. This proposal would require inspections of the linear variable differential transducers (LVDTs) of the autopilot for discrepancies, and follow-on actions, if necessary. This action is necessary to prevent failure of the LVDTs, which could result in an automatic pitch trim malfunction or an autopilot disconnect, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 7, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-358-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. 2001-NM-358-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:

Technical Information: 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].

Other Information: Sandi Carli, Airworthiness Directive Technical Editor/Writer; telephone [phone], fax [phone]. Questions or comments may also be sent via the Internet using the following address: [e-mail]. Questions or comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

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 2001-NM-358-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. 2001-NM-358-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has been informed by the manufacturer that certain McDonnell Douglas Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F, DC-10-30F (KC10A and KDC-10), MD-10-10F, and MD-10-30F airplanes having linear variable differential transducers (LVDT) were delivered with an undersize nylok element on the threaded extension end. If such undersizing is not corrected, the LVDT plunger jamnut could become loose causing an automatic pitch trim malfunction, an elevator stand-off resulting in automatic pitch trim operation in one direction only, or an autopilot disconnect.

Also, we received one report of a pitch trim incident in flight that resulted in an uncommanded nose-down pitch of the airplane. Investigation revealed that the cause of that incident was loose shear rivets in the drive assembly of the automatic pitch trim LVDT. The loose shear rivets allowed the automatic pitch trim LVDT to shift enough to command the horizontal stabilizer to put the airplane in a nose-down direction. Further investigation revealed additional airplanes with loose rivets, and one airplane with an additional problem with the attachment to the automatic pitch trim LVDT. Binding between the plunger and body of the LVDT due to loose rivets can cause failure of the LVDT shear rivets. Such conditions, if not corrected, could result in an automatic pitch trim malfunction and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin DC10-22A126, dated October 31, 2001, which describes procedures for a visual inspection of the shear rivets of the LVDTs of the drive assembly of the automatic pitch trim for discrepancies (sheared and/or loose rivets), and these six follow-on conditions:

• Condition 1: If no sheared or loose rivets are found, no further action is needed.
• Condition 2: If any sheared and/or loose rivets are found, repair the drive assembly and repeat visual inspection of the LVDT for further discrepancies (misalignment, corrosion, bent plunger, restricted movement, or hangar binding). If no discrepancy is found, no further action is needed.
• Condition 3: If a discrepancy is found after doing Condition 2, do the corrective actions specified in Conditions 4 through 6, as applicable.
• Condition 4: If the LVDT is misaligned, realign.
• Condition 5: If any corrosion, a bent plunger, or restricted movement of the LVDT is found, replace the existing LVDT with a new LVDT.
• Condition 6: If hangar binding of the LVDT is found, replace the LVDT hangar assembly with a new assembly.

We also have reviewed and approved Boeing Alert Service Bulletin DC10-22A127, dated December 17, 2001, which describes procedures for a visual inspection of the LVDTs for affected serial numbers (with an undersize nylok element) and these two options for follow-on actions:

• Option 1: Replace any affected LVDT with a new LVDT; then do the automatic pitch trim adjustment/test.
• Option 2: Install a heat shrinkable sleeve over the LVDT jamnut; then do repetitive inspections for loose LVDT jamnuts until the LVDT is replaced.

Accomplishment of the actions specified in the service bulletins 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 bulletins described previously, except as discussed below.

Difference Between This Proposed AD and the Service Information

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

Explanation of AD Applicability

We have specified model designations in the applicability of this proposed AD as published in the most recent type certificate data sheet for the affected models. These model designations differ in the referenced service bulletins.

Cost Impact

There are approximately 394 airplanes of the affected design in the worldwide fleet. The FAA estimates that 252 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 1 work hour per airplane to accomplish the inspection specified in Boeing Alert Service Bulletin DC10-22A126, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this proposed inspection on U.S. operators is estimated to be $15,120, or $60 per airplane.

It would take approximately 1 work hour per airplane to accomplish the inspection specified in Boeing Alert Service Bulletin DC10-22A127, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this proposed inspection on U.S. operators is estimated to be $15,120, or $60 per airplane.

The cost impact figures discussed above are 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.

Should an operator be required to perform the follow-on actions specified in Boeing Alert Service Bulletin DC10-22A126, the cost estimates are as follows:

• Condition 2—Repair/inspect: 1 work hour per airplane at $60 per work hour.
• Condition 4—Realign: 1 work hour per airplane at $60 per work hour.
• Condition 5—Replace LVDT: 1 work hour per airplane at $60 per work hour; estimated parts cost of $900.
• Condition 5—Replace hangar: 1 work hour per airplane at $60 per work hour; estimated parts cost of $100.

Should an operator be required to perform the follow-on actions specified in Boeing Alert Service Bulletin DC10-22A127, the cost estimates are as follows:

• Option 1—Replace LVDT and do adjustment/test: 2 work hours per airplane at $60 per work hour; estimated parts cost of $900.
• Option 2—Install a heat shrinkable sleeve and inspect: 2 work hours per airplane at $60 per work hour.

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 2001-NM-358-AD.

Applicability: Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F, DC-10-30F (KC10A and KDC-10), MD-10-10F, and MD-10-30F airplanes; as listed in Boeing Alert Service Bulletin DC10-22A126, dated October 31, 2001; and Boeing Alert Service Bulletin DC10-22A127, dated December 17, 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 (c) 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 the linear variable differential transducers (LVDTs) of the autopilot, which could result in an automatic pitch trim malfunction or an autopilot disconnect, and consequent reduced controllability of the airplane, accomplish the following:

Detailed Inspections/Follow-On Actions

(a) Within 90 days after the effective date of this AD: Do the detailed inspections of the LVDTs of the autopilot for discrepancies as required by paragraphs (a)(1) and (a)(2) of this AD.

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) Inspect the LVDTs for affected serial numbers (with undersize nylok elements) per Figure 1 of Boeing Alert Service Bulletin DC10-22A127, dated December 17, 2001. If any affected serial number is found, before further flight, do either Option 1 (including replacing the LVDT with a new LVDT and doing an automatic pitch trim adjustment/test), or Option 2 (including installing a heat-shrinkable sleeve over the LVDT jamnut and doing repetitive inspections for any loose jamnut every 500 flight hours until the LVDT is replaced with a new LVDT), of Condition 1 of the service bulletin, per the service bulletin. If any discrepancy is found, before further flight, replace the LVDT with a new LVDT. If no discrepancy is found, install a shield assembly per Condition 2 of the service bulletin.

(2) Inspect the shear rivets of the LVDTs of the drive assembly of the automatic pitch trim for discrepancies (shearing and/or looseness), per Boeing Alert Service Bulletin DC10-22A126, dated October 31, 2001. If any discrepancy is found, before further flight, do Conditions 2 through 6 (including repairing the driver assembly and inspecting the LVDT within 9 months after doing the repair; doing an automatic pitch trim adjustment/test; aligning the LVDT; replacing the existing LVDT with a new LVDT; and replacing the hangar assembly with a new assembly), as applicable, of the service bulletin, per the service bulletin. If no discrepancy is found, no further action is required by this paragraph.

Spares

(b) As of the effective date of this AD, no one may install an LVDT with a serial number listed in the “Affected Serial Numbers” table in Figure 1 of Boeing Alert Service Bulletin DC10-22A127, dated December 17, 2001, on any airplane.

Alternative Methods of Compliance

(c) 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, 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 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

(d) 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 August 19, 2002.

Vi L. Lipski,

Manager, , Transport Airplane Directorate, Aircraft Certification Service.