AD 97-25-14

This amendment adopts a new airworthiness directive (AD), applicable to certain de Havilland Model DHC-8-100, -200, and -300 series airplanes, that requires repetitive inspections of certain refuel/defuel tube assemblies in the engine nacelles for fuel leakage, and corrective action, if necessary. This amendment will also require eventual modification of all tube assemblies, which will terminate the repetitive inspections. 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 fuel leaks and consequent increased risk of engine fires.

Final Rule

97-25-14 DE HAVILLAND, INC.: Amendment 39-10238. Docket 97-NM-120-AD.

Applicability: Model DHC-8-100, -200, and -300 series airplanes; as listed in Bombardier Alert Service Bulletin S.B. A8-28-20, Revision `A,' dated September 10, 1996; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (f) 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 fuel leaks and consequent increased risk of engine fires, accomplish the following:

(a) Within 30 days after the effective date of this AD, inspect the five refuel/defuel tube assemblies in the engine nacelles to detect fuel leaks, in accordance with Part 1 of the Accomplishment Instructions of Bombardier Alert Service Bulletin S.B. A8-28-20, Revision `A', dated September 10, 1996. If any fuel leak is found, prior to further flight, replace the refuel/defuel tube assembly with an improved assembly, in accordance with the alert service bulletin. Thereafter, repeat the inspection at intervals not to exceed 6 months.

(b) Within 12 months after the effective date of this AD, modify the refuel/defuel tube assembly located under the exhaust fingernail on the engine nacelle, as specified in Part 2 of the Accomplishment Instructions of Bombardier Alert Service Bulletin S.B.A8-28-20, Revision `A,' dated September 10, 1996, in accordance with the procedures specified in the alert service bulletin.

(c) Within 24 months after the effective date of this AD, modify the remaining refuel/defuel tube assemblies, as specified in Part 3 of the Accomplishment Instructions of Bombardier Alert Service Bulletin S.B. A8-28-20, Revision `A,' dated September 10, 1996, in accordance with the procedures specified in the alert service bulletin.

(d) Accomplishment of the modifications required by paragraphs (b) and (c) of this AD constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD.

(e) As of the effective date of this AD, no person shall install a refuel/defuel tube assembly having part number 82820107-007, 82821015-003, 82820108-005, 82820245-001, 82820246-001, 82820247-001, or 82821014-001, on any airplane.

(f) An alternative method of compliance or adjustment of the compliance time that provides an acceptablelevel 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.

(g) 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.

(h) The actions shall be done in accordance with Bombardier Alert Service Bulletin S.B. A8-28-20, Revision `A,' dated September 10, 1996. 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., Canadair, Aerospace Group, P.O. Box 6087, Station A, Montreal, Quebec H3C 3G9, 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- 96-14, dated August 20, 1996.

(i) This amendment becomes effective on January 14, 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 de Havilland Model DHC-8-100, -200, and -300 series airplanes was published in the Federal Register on October 6, 1997 (62 FR 52051). That action proposed to require repetitive inspections of certain refuel/defuel tube assemblies in the engine nacelles for fuel leakage, and corrective action, if necessary. It also proposed to require eventual modification of all tube assemblies, which would terminate the repetitive inspections.

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

The FAA estimates that 95 Model DHC-8-100, -200, and -300 series airplanes of U.S. registry will be affected by this AD.

The inspection will take approximately 6 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $34,200, or $360 per airplane, per inspection cycle.

The modification (specified in Part 2 of the Accomplishment Instructions in the referenced alert service bulletin) will take approximately 15 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $500. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $133,000, or $1,400 per airplane.

The modification (specified in Part 3 of the Accomplishment Instructions in the referenced service bulletin) will take approximately 36 work hours per airplaneto accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,600 per airplane. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $357,200, or $3,760 per airplane.

The cost impact figures discussed above are 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.

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: