AD 2003-25-03

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-400, -401, and -402 airplanes, that requires a one-time inspection of the forward engine mount assemblies on the left and right engine nacelles for installation of pre-production engine mount assemblies, and follow-on corrective actions if necessary. This action is necessary to prevent failure of the forward engine mount, which could result in reduced structural integrity of the nacelle and engine support structure. This action is intended to address the identified unsafe condition.

Final rule.

2003-25-03 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 39-13386. Docket 2002-NM-78-AD.

Applicability: Model DHC-8-400, -401, and -402 airplanes; serial numbers 4005, 4006, 4008 through 4016 inclusive, 4018 through 4051 inclusive, and 4053; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the forward engine mount, which could result in reduced structural integrity of the nacelle and engine support structure, accomplish the following:

Inspection

(a) Within 100 flight cycles after the effective date of this AD: Do a general visual inspection of the forward engine mount assemblies on the left and right engine nacelles for installation of pre-production assemblies (determine the part number and configuration for each assembly), per the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-71-06, Revision "A," dated December 5, 2001. If no pre-production engine mount assembly is installed, no further action is required by this AD.

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."

Follow-on Corrective Actions

(b) If any pre-production engine mount assembly is installed, do all the applicable follow-on corrective actions (including repetitive detailed inspections for cracking, and rework or replacement ofthe pre-production engine mount assembly if necessary), per all the actions specified in the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-71-06, Revision "A," dated December 5, 2001, at the applicable times specified in Paragraph I., Part D., "Compliance," of the service bulletin. Any replacement due to cracking must be done before further flight.

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."

Optional Terminating Action for Follow-on Repetitive Inspections

(c) Installation of production engine mount assemblies on allfour forward engine mounts ends the repetitive inspection requirements of paragraph (b) of this AD.

Part Installation

(d) As of the effective date of this AD, no person may install an engine mount assembly having a pre-production configuration and/ or part number 96042-07 on any airplane, unless the assembly has been reworked per Part B of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-71-06, Revision "A," dated December 5, 2001.

Alternative Methods of Compliance

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

Incorporation by Reference

(f) Unless otherwise provided in this AD, the actions shall be done per Bombardier Alert Service Bulletin A84-71-06, Revision "A," dated December 5, 2001. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFRpart 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; or at the FAA, 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-2002-07, dated January 21, 2002.

Effective Date

(g) This amendment becomes effective on January 22, 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- 400, -401, and -402 airplanes was published in the Federal Register on October 9, 2003 (68 FR 58287). That action proposed to require a one- time inspection of the forward engine mount assemblies on the left and right engine nacelles for installation of pre-production engine mount assemblies, and follow-on corrective actions if necessary.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion

The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact

We estimate that 11 airplanes of U.S. registry will be affected by this AD,that it will take approximately 2 work hours per airplane to accomplish the required inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $1,430, or $130 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: