AD 2002-03-12

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-400 series airplanes, that requires a modification and a replacement affecting the fuel tanks in the wings. All affected airplanes require modification of the clearance of the fuel tank vent lines to the left and the right wing fuel tanks. Some affected airplanes also require replacement of three existing fuel probes from the center fuel tank on the left and right wings with new production fuel probes. This action is prompted by mandatory continuing airworthiness information from a foreign airworthiness authority. The actions specified by this AD are necessary to prevent inadequate clearance between the fuel tank vent lines and the adjacent rib structures of the wings or failure of certain temporary, reworked fuel probes in the center fuel tanks in the wings. Either condition could compromise the airplane's lightning protection system, possibly resulting in a fire or explosion if the airplane were hit by lightning. This action is intended to address the identified unsafe condition.

Final rule.

2002-03-12 Bombardier, Inc. (Formerly de Havilland, Inc.): Amendment 39-12653. Docket 2001-NM-140-AD.

Applicability: Model DHC-8-400 series airplanes; certificated in any category; serial numbers 4005, 4006, 4008 through 4010 inclusive, 4012 through 4015 inclusive, and 4018 through 4040 inclusive.

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 (c) 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 includespecific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent inadequate clearance between the fuel tank vent lines and the adjacent rib structures of the wings or failure of certain temporary, reworked fuel probes in the center fuel tanks in the wings, either of which could compromise the airplane's lightning protection system, possibly resulting in a fire or explosion if the airplane were hit by lightning, accomplish the following:

Modification of Clearance of Fuel Tank Vent Lines

(a) For airplanes having serial numbers 4005, 4006, 4008 through 4010 inclusive, 4012 through 4015 inclusive, and 4018 through 4040 inclusive: Within 120 days after the effective date of this AD, modify the clearance of the fuel tank vent lines to the left and the right wing fuel tanks by wrapping 1 piece of Teflon tube around the vent line at each of 10 stations (2 pieces at station 191.200) and securing it with a clamping band (2clamping bands at station 191.200), in accordance with the Accomplishment Instructions (including Table 1) and Figure 1 of Bombardier Alert Service Bulletin A84-28-02, dated February 7, 2001.

Replacement of Fuel Probes Numbers 1, 2, and 5

(b) For airplanes having serial numbers 4006, 4008, 4012 through 4015 inclusive, and 4018 through 4027 inclusive: Prior to the accumulation of 4,000 total flight hours or within 120 days after the effective date of this AD, whichever occurs later: Replace existing fuel probes numbers 1, 2, and 5 from the center fuel tank on the left and the right wings with new production fuel probes, in accordance with Bombardier Service Bulletin 84-28-01, Revision "A," dated February 8, 2001.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA. 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.

Special Flight Permits

(d) 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.

Incorporation by Reference

(e) The actions shall be done in accordance with Bombardier Alert Service Bulletin A84-28-02, dated February 7, 2001; and Bombardier Service Bulletin 84-28-01, Revision "A," dated February 8, 2001; as applicable. 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 fromBombardier, 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-2001-14, dated March 21, 2001.

Effective Date

(f) This amendment becomes effective on March 27, 2002.

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 series airplanes was published in the Federal Register on November 19, 2001 (66 FR 57905). That action proposed to require two actions--a modification and a replacement--affecting the fuel tanks in the wings. All affected airplanes would require modification of the clearance of the fuel tank vent lines to the left and the right wing fuel tanks. Some affected airplanes would also require replacement of three existing fuel probes from the center fuel tank on the left and right wings with new production fuel probes.

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.

Explanation of Change to Final RuleSince the issuance of the notice of proposed rulemaking (NPRM), the FAA has found that paragraph (b) of the NPRM needs to be clarified. That paragraph requires that replacement of the existing fuel probes 1, 2, and 5 with new production fuel probes be accomplished "Prior to the accumulation of 4,000 flight hours * * *" It was our intent that the replacement be accomplished prior to the accumulation of 4,000 "total" flight hours. Therefore, we have revised paragraph (b) of the final rule to specify total flight hours.

Conclusion

After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the 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

There are approximately 32 airplanes of the affected design in the worldwide fleet. The FAA estimates that 15 airplanes of U.S. registry will be affected by this AD.

Thirteen airplanes of U.S. registry will be affected by the required modification of the clearance of the fuel tank vent line. It will take approximately 12 work hours to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will cost approximately $440 per airplane. Based on these figures, the cost impact of the required modification on U.S. operators is estimated to be $15,080, or $1,160 per airplane.

Seven airplanes of U.S. registry will be affected by the required replacement of the numbers 1, 2, and 5 fuel probes. It will take approximately 2 work hours to accomplish the required replacement, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the required replacement on U.S. operators is estimated to be $840, or $120 per airplane.

The cost impact figures discussedabove 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. 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 continuesto read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive: