03-27213. Airworthiness Directives; McDonnell Douglas Model DC-9-31 and DC-9-32 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-9-31 and DC-9-32 airplanes. This proposal would require replacement of certain power relays, and subsequent repetitive cleaning, inspecting, repairing, and testing of certain replaced power relays. This action is necessary to prevent internal arcing of the left and right generator power relays, auxiliary power relays, and external power relays, and consequent smoke and/or fire in the cockpit and cabin. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by December 15, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-32-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. 2003-NM-32-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 or 2000 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:

Elvin Wheeler, Aerospace Engineer, Systems and Equipment Branch, ANM-130L, 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 2003-NM-32-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. 2003-NM-32-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports indicating that the alternating current (AC) cross-tie relay shorted out internally on McDonnell Douglas Model DC-9 series airplanes, which caused severe smoke and burn damage to the relay, aircraft wiring, and adjacent panels. Investigation revealed that the electrical fire originated within the cross-tie relay of the power distribution system. The cause of this incident has been attributed to a phase-to-phase short within the relay. This condition, if not corrected, could result in in-flight electrical fires.

Other Relevant Rulemaking

We have previously issued AD 2002-26-13, amendment 39-13001 (68 FR 33, January 2, 2003), applicable to certain McDonnell Douglas airplane models, as follows:

DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, and DC-9-15F airplanes.

DC-9-21 airplanes.

DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-32F (C-9A, C-9B), DC-9-33F, DC-9-34, and DC-9-34F airplanes.

DC-9-41 airplanes.

DC-9-51 airplanes.

DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) airplanes.

MD-88 airplanes.

That AD requires replacement of certain power relays, and subsequent repetitive cleaning, inspecting, repairing, and testing of certain replaced power relays. The actions specified by that AD are intended to prevent internal arcing of the left and right generator power relays, auxiliary power relays, and external power relays, and consequent smoke and/or fire in the cockpit and cabin.

Since issuance of AD 2002-26-13, we have determined that the same unsafe condition addressed in that AD may exist on four additional Model DC-9 series airplanes. We were advised that Model DC-9-31 airplanes having manufacturer's fuselage numbers 1039 and 1046, and Model DC-9-32 having manufacturer's fuselage numbers 0268 and 0505 were omitted inadvertently from the applicability of that AD because those airplanes had been excluded inadvertently from the effectivity of paragraph 1.A of Boeing Alert Service Bulletin DC9-24A191, Revision 01, dated January 9, 2002, as cited in AD 2002-26-13. Therefore, these additional airplanes are also subject to the same unsafe condition addressed in AD 2002-26-13.

Explanation of Relevant Service Information

We have reviewed and approved Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003. The service bulletin describes procedures for a one-time inspection of the generator power relays, auxiliary power relays, and external power relays to determine if a certain Sundstrand (Westinghouse) part number (P/N) is installed; and corrective actions, if necessary. The corrective actions include modifying and reidentifying the power relay assemblies; installing certain power relay assemblies within service interval limits; replacing the existing power relay assemblies with power relay assemblies that are within service interval limits; and cleaning, inspecting, repairing, and testing of relay assemblies; as applicable. The revised service bulletin adds four fuselage numbers to the effectivity. No more work is necessary on airplanes changed as shown in Revision 01 of this service bulletin. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

The procedures specified by Revision 02 of the service bulletin are essentially the same as those procedures specified in the Revision 01 Boeing Alert Service Bulletin DC9-24A191.

Accomplishment of the actions specified in AD 2002-26-13 is acceptable for compliance with the requirements of this proposed AD.

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 as discussed below.

Since this proposed AD expands the applicability of AD 2002-26-13, we have considered a number of factors in determining whether to issue a new proposed AD or to supersede the “old” AD. We have considered the entire fleet size that would be affected by superseding AD 2002-26-13 and the consequent workload associated with revising maintenance record entries. In light of this, we have determined that a less burdensome approach is to issue a separate AD applicable only to the four additional airplanes. This proposed AD would not supersede AD 2002-26-13; airplanes listed in the applicability of AD 2002-26-13 are required to continue to comply with the requirements of that AD. This proposed AD is a separate AD action, and is applicable only to McDonnell Douglas Model DC-9-31 airplanes having manufacturer's fuselage numbers 1039 and 1046, and Model DC-9-32 airplanes having manufacturer's fuselage numbers 0268 and 0505; certificated in any category.

Differences Between Relevant Service Information and Proposed Rule

Operators should note that, although the procedures described in Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003, specify maintenance (i.e., clean, inspect, repair, and test) of power relays, Sundstrand (Westinghouse) P/N 9008D09 series, when they are beyond service interval limits, this proposed AD would not require those procedures. The design of the main contact arc box for this relay is entirely different than that of power relays, Sundstrand (Westinghouse) P/Ns 914F567-3 and -4, and is not susceptible to the same type of failure in the AC cross-tie position. Therefore, we have determined that power relays having Sundstrand (Westinghouse) P/N 9008D09 series are not subject to the identified unsafe condition of this proposed AD.

Operators should also note that the proposed AD would not require installation of certain power relays or replacement of the existing power relays with power relays that are “within service interval limits” (i.e., 7,000 flight hours) as described in the service bulletin. The FAA has determined that any generator power relay, auxiliary power relay, or external power relay having Sundstrand (Westinghouse) P/N 914F567-4 that is removed from the airplane must go through maintenance and be made serviceable before the power relay can be reinstalled on an airplane. Therefore, the proposed AD would require cleaning, inspecting, repairing, and testing of power relays having Sundstrand (Westinghouse) P/N 914F567-4, or replacing those power relays with serviceable power relays having Sundstrand (Westinghouse) P/N 9008D09 series or 914F567-4. The proposed AD also would require subsequent repetitive cleaning, inspecting, repairing, and testing of power relays having Sundstrand (Westinghouse) P/N 914F567-4.

Cost Impact

There are approximately 4 airplanes of the affected design in the worldwide fleet. The FAA estimates that 2 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 2 work hours per airplane to accomplish the proposed inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $260, or $130 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 2003-NM-32-AD.

Applicability: Model DC-9-31 airplanes having manufacturer's fuselage numbers 1039 and 1046, and Model DC-9-32 airplanes having manufacturer's fuselage numbers 0268 and 0505; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent internal arcing of the left and right generator power relays, auxiliary power relays, and external power relays, and consequent smoke and/or fire in the cockpit and cabin, accomplish the following:

Inspection

(a) Within 24 months after the effective date of this AD, perform a one-time inspection of the left and right generator power relays, auxiliary power relays, and external power relays, to determine if Sundstrand (Westinghouse) part number (P/N) 914F567-3 or -4 is installed, per Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003.

Replacement or Modification/Reidentification of Any Generator Power Relay, Auxiliary Power Relay, or External Power Relay, P/N 914F567-3

(b) If any generator power relay, auxiliary power relay, or external power relay, Sundstrand (Westinghouse) P/N 914F567-3, is found installed during the inspection required by paragraph (a) of this AD, within 24 months after the effective date of this AD, do either action specified in paragraph (b)(1) or (b)(2) of this AD per the Accomplishment Instructions of Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003.

(1) Replace the power relay having Sundstrand (Westinghouse) P/N 914F567-3 with either a serviceable power relay having Sundstrand (Westinghouse) P/N 9008D09 series or 914F567-4.

(2) Modify the power relay, Sundstrand (Westinghouse) P/N 914F567-3, to a -4 configuration.

Maintenance or Replacement of Any Generator Power Relay, Auxiliary Power Relay, or External Power Relay, P/N 914F567-4

(c) If any generator power relay, auxiliary power relay, or external power relay, Sundstrand (Westinghouse) P/N 914F567-4, is found installed during the inspection required by paragraph (a) of this AD, clean, inspect, repair, and test the relay, or replace the power relay with a serviceable power relay having Sundstrand (Westinghouse) P/N 9008D09 series or 914F567-4; per Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003; at the time specified in paragraph (c)(1) of this AD, except as provided by paragraph (c)(2) of this AD.

(1) Within 7,000 flight hours after installation of the generator power relay, auxiliary power relay, or external power relay, Sundstrand (Westinghouse) P/N 914F567-4, or within 24 months after the effective date of this AD, whichever occurs later.

(2) For airplanes on which the flight hours since installation of any generator power relay, auxiliary power relay, or external power relay, Sundstrand (Westinghouse) P/N 914F567-4, cannot be determined: Within 24 months after the effective date of this AD.

Repetitive Maintenance of Generator Power Relay, Auxiliary Power Relay, or External Power Relay, Sundstrand (Westinghouse) P/N 914F567-4

(d) Before or upon the accumulation of 7,000 flight hours on any generator power relay, auxiliary power relay, or external power relay, Sundstrand (Westinghouse) P/N 914F567-4 since accomplishing the action(s) required by either paragraph (b) or (c) of this AD, as applicable, clean, inspect, repair, and test; per Boeing Alert Service Bulletin DC9-24A191, Revision 02, dated January 7, 2003. Thereafter, repeat these actions at intervals not to exceed the accumulation of 7,000 flight hours on the power relay.

Credit for AD 2002-26-13, Amendment 39-13001

(e) Accomplishment of the actions specified in AD 2002-26-13 is acceptable for compliance with the requirements of this AD.

Alternative Methods of Compliance

(f) In accordance with 14 CFR 39.19, the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.

Issued in Renton, Washington, on October 23, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.