AD 98-20-23

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes, that requires a one-time inspection to detect discrepancies in the electrical wiring and wiring harness behind the lavatory, and corrective actions. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent chafing of electrical wiring, which could result in severe overheating of the wiring, consequent smoke in the flight deck and cabin, and possible injury to flightcrew or passengers.

Final Rule

98-20-23 BOMBARDIER, INC. (Formerly de Havilland, Inc.): Amendment 39-10789. Docket 98-NM-14-AD.

Applicability: Model DHC-8-100, -200, and -300 series airplanes, serial numbers 003 through 433 inclusive, except 031, 408, and 413; 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 addressit.

Compliance: Required as indicated, unless accomplished previously.

To prevent chafing of electrical wiring, which could result in severe overheating of the wiring, consequent smoke in the flight deck and cabin, and possible injury to flightcrew or passengers, accomplish the following:

(a) Within 9 months after the effective date of this AD, perform a one-time inspection to detect discrepancies in the electrical wiring or wiring harness located behind the lavatory, in accordance with Bombardier Service Bulletin S.B. 8-24-50, dated April 25, 1997.

(1) If no discrepancy is found, prior to further flight, modify the wiring harness and the lavatory forward panel, in accordance with the service bulletin.

(2) If any discrepancy is found, prior to further flight, repair it and modify the wiring harness and the lavatory forward panel, in accordance with the service bulletin.

(b) An alternative method of compliance or adjustment of the compliance time that providesan acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(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.

(d) The actions shall be done in accordance with Bombardier Service Bulletin S.B. 8-24-50, dated April 25, 1997. This incorporation by reference was approved by the Director of the Federal Register 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, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Canadian airworthiness directive CF-97-14, dated July 22, 1997.

(e) This amendment becomes effective on October 27, 1998.

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-8-100, -200, and -300 series airplanes was published in the Federal Register on April 2, 1998 (63 FR 16174). That action proposed to require a one-time inspection to detect discrepancies in the electrical wiring and wiring harness behind the lavatory, and corrective actions.

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.

The commenter requests that the compliance time for the one-time inspection and modification be changed from the proposed 9 months to 5 years. The commenter states that each of its airplanes would have to use weekend maintenance slots for the modification because of the lengthy down time required to accomplish the proposed actions. This would mean the commenter could accomplish two airplanes per week; and at that rate, it would take 6 months of weekends to accomplish the entire fleet. Further, the commenter notes that the proposed 9-month compliance time would result in other needed maintenance/modifications being neglected during that period. The commenter s request to extend the compliance time to 5 years is based on the merits of its history with the airplane model, and the fact that the Bombardier service bulletin recommends accomplishment of the service bulletin "at the operator s earliest opportunity."

The FAA does not concur with the commenter s request to extend the compliance time to 5 years since the commenter provided no technical justification for extending the compliance time. Furthermore, in developing an appropriate compliance time for this action, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the normal maintenance schedules for timelyaccomplishment of the inspection and modification. The FAA also considered the fact that the referenced Bombardier service bulletin (containing the procedures for accomplishing the required actions) has been available to all operators of the Model DHC-8-100, -200, and -300 series airplanes since April 1997; therefore, U.S. operators have had ample time since then to consider initiating those actions, which this AD ultimately mandates. However, under the provisions of paragraph (b) of the final rule, the FAA may approve requests for adjustments to the compliance time if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety.

Change to the Rule

The FAA has revised this final rule to specify the manufacturer s name change from de Havilland to Bombardier.

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 ofthe rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

The FAA estimates that 163 airplanes of U.S. registry will be affected by this proposed AD. It will take approximately 1 work hour per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on this figure, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $9,780, or $60 per airplane.

It will take approximately 20 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $195,600 or $1,200 per airplane.

The cost impact figures discussed above are basedon 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.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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: