AD 2004-06-08

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-401 and -402 airplanes, that requires modifying the wiring of the rudder trim switch, inspecting all wiring on the back of the aileron/rudder trim control panel for chafing, and replacing any chafed wiring with new wiring. This action is necessary to prevent a short circuit on the aileron/ rudder trim control panel that could cause a runaway condition of the rudder trim actuator, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2004-06-08 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 39-13534. Docket 2002-NM-120-AD.

Applicability: Model DHC-8-401 and -402 airplanes; certificated in any category; serial numbers 4005, 4006, 4008 through 4016 inclusive, and 4018 through 4058 inclusive.

Compliance: Required as indicated, unless accomplished previously.

To prevent a short circuit on the aileron/rudder trim control panel that could cause a runaway condition of the rudder trim actuator, which could result in reduced controllability of the airplane, accomplish the following:

Modification, Inspection, and Corrective Action

(a) Within 90 days after the effective date of this AD, do the actions in paragraphs (a)(1) and (a)(2) of this AD, per the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-27-13, Revision "B," dated January 12, 2002.

(1) Modify the wiring of the rudder trim switch.

(2) Before further flight after accomplishing the modification required by paragraph (a)(1) of this AD: Perform a one-time general visual inspection of all wiring on the back of the aileron/rudder trim control panel for chafing. Before further flight, replace any chafed wiring with new wiring.

Note 1: For the purposes of this AD, a general visual inspection is defined as: "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked."

Previously Accomplished Actions

(b) Modifications and inspections accomplished before the effective date of this AD per Bombardier Alert Service Bulletin A84- 27-13, Revision "A," dated January 9, 2002, are acceptable for compliance with the corresponding actions required by paragraph (a) of this AD.

Parts Installation

(c) As of the effective date of this AD, no person may install aileron/rudder trim control panel having part number 82410608-005 on any airplane, unless the control panel has been modified and inspected per the requirements of this AD.

Alternative Methods of Compliance

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

Incorporation by Reference

(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Bombardier Alert Service Bulletin A84-27-13, Revision "B," dated January 12, 2002. This incorporation by reference was approved by the Director of the FederalRegister in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; at the FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 2: The subject of this AD is addressed in Canadian airworthiness directive CF-2002-15, dated February 20, 2002.

Effective Date

(f) This amendment becomes effective on April 29, 2004.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-401 and -402 airplanes was published in the Federal Register on November 17, 2003 (68 FR 64825). That action proposed to require modifying the wiring of the rudder trim switch, inspecting all wiring on the back of the aileron/rudder trim control panel for chafing, and replacing any chafed wiring with new wiring.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received.

Request To Give Credit for Previous Revisions of Service Information

While the commenter states that it has no objection to the proposed AD, it requests that the proposed AD be revised to give credit for actions accomplished previously per the original issue of Bombardier Alert Service Bulletin A84-27-13, dated January 2, 2002; or per Revision "A" of that service bulletin, dated January 9, 2002. (Paragraph (a) of the proposed AD refers to Bombardier Alert Service Bulletin A84-27-13, Revision "B," dated January 12, 2002, as the appropriate source of service information for the actions required by that paragraph.) The commenter states that the original issue and Revision "A" of the service bulletin accomplish the same intent as Revision "B." The commenter notes that this change to the proposed AD would prevent operators from having to request approval of an alternative means of compliance with the proposed AD.

We partially concur with the commenter's request. We note that paragraph (b) of this AD states that actions accomplished before the effective date of this AD per Bombardier Alert Service Bulletin A84-27- 13, Revision "A," are acceptable for compliance with paragraph (a) of this AD. However, with respect to the commenter's request that we also give credit for use of the original issue of the service bulletin, we note that the Accomplishment Instructions of the original issue of the service bulletin omit several steps, including steps pertaining to rework of wiring of spare trim panels and marking the new part number on modified trim panels. We find that these missing instructions could allow improper modification of the affected panels and improper rework of the wiring. Thus, we find that it is not appropriate to give credit for actions accomplished per the original issue of the service bulletin. We have made no change to the final rule.

Conclusion

After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact

The FAA estimates that 12 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required actions, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $780, or $65 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the 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 adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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: