AD 2001-22-08

This amendment adopts a new airworthiness directive (AD), applicable to all Fokker Model F.28 series airplanes, that requires replacing the main landing gear (MLG) torque link dampers with modified and reidentified dampers. This action is necessary to prevent degradation of the dampers, which could result in MLG high amplitude oscillation in a lateral torsional mode, and consequent MLG damage or separation of the MLG from the airplane. This action is intended to address the identified unsafe condition.

Final rule

2001-22-08 Fokker Services B.V.: Amendment 39-12487. Docket 2001-NM-208-AD.

Applicability: All Model F.28 series airplanes, 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 (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 include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent separation of the main landing gear (MLG) from the airplane due to performance degradation of the torque link damper, accomplish the following:

Modification and Reidentification

(a) Replace MLG torque link dampers having part numbers (P/N) 23700-1 or -3 with dampers having P/N 23700-5, in accordance with the Accomplishment Instructions of Fokker Service Bulletin (SB) SBF28/32-157 (for Models F.28 Mark 1000 through 4000 series airplanes) or Fokker Service Bulletin SBF100-32-114 (for Model F.28 Mark 0070/0100 series airplanes), both dated October 1, 1999, as applicable; at the times specified in the following table:

Table 1.--Compliance Times

Fokker F.28 model (mark) designation
MLG manufactured by
MLG mod. status
Compliance required after the effective date of this AD
(1) Mk.0100
Dowty Aerospace; MD
Pre-Mod SB F100-32-50
Within 15 months.
(2) Mk.0100
Dowty Aerospace; MD
Post-Mod SB F100-32-50
Within 21 months.
(3) Mk.0100
Menasco Aerospace
[Reserved]
Within 24 months.(4) Mk.0070
Menasco Aerospace
[Reserved]
Within 24 months.
(5) Mk.1000 through Mk.4000 series
Dowty Aerospace; MD
[Reserved]
Within 24 months.

Note 2: Installation of torque link dampers with P/N 23700-7 in accordance with Fokker Service Bulletin SBF28/32-159, dated October 1, 1999 (for Models F.28 Mark 1000 through 4000 series airplanes), or SBF100-32-116, dated February 1, 2000 (for Model F.28 Mark 0070/0100 series airplanes), as applicable, is acceptable for compliance with paragraph (a) of this AD.

Spares

(b) As of the effective date of this AD, no person shall install torque link damper having P/N 23700-1 or -3, on any airplane.

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, International Branch, ANM-116, Transport Airplane Directorate, FAA. Operators shall submit their requests through an appropriate FAAPrincipal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

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 Fokker Service Bulletin SBF28/32-157, dated October 1, 1999; or Fokker Service Bulletin SBF100-32-114, dated October 1, 1999; 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 from Fokker Services B.V., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 4: The subject of this AD is addressed in Dutch airworthiness directive 1999-138, dated October 29, 1999.

Effective Date

(f) This amendment becomes effective on December 4, 2001.

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 all Fokker Model F.28 series airplanes was published in the Federal Register on August 17, 2001 (66 FR 43124). That action proposed to require replacing the main landing gear (MLG) torque link dampers with modified and reidentified dampers.

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.

Allow Use of New-Configuration Dampers

The commenter requests that the FAA revise paragraph (a) of the proposed rule to allow an operator to install a torque link damper with a dash number higher than (23700)-5. The commenter states that it has already modified its entire inventory of torque link dampers to the configuration of part number 23700-7. The commenter states that revising the proposed AD to allow installation of parts modified to a configuration subsequent to that of part number 23700-5 would relieve it and other operators of the need to request approval of alternative methods of compliance (AMOCs).

The FAA partially concurs with the commenter's request. Because we cannot approve installation of dampers that do not exist, we do not concur to revise paragraph (a) of the proposed AD in the specific way the commenter suggests.

However, since the issuance of the proposed rule, we have reviewed Fokker Service Bulletins SBF28/32-159, dated October 1, 1999 (for Models F.28 Mark 1000 through 4000 series airplanes), and SBF100-32-116, dated February 1, 2000 (for Model F.28 Mark 0070/0100 series airplanes). Those service bulletins specify replacement of existing torque link dampers with modified dampers, and refer to Menasco Aerospace Service Bulletin 23700-32-15, dated September 3, 1999, as an appropriate source of service information for modifying torque link dampers with part number 23700-1, -3, or -5, to part number 23700-7. In consideration of these service bulletins, we have added a new Note 2 to this final rule to state that installation of torque link dampers with part number 23700-7 in accordance with Fokker Service Bulletin SBF28/32-159 or SBF100-32-116, as applicable, is acceptable for compliance with paragraph (a) of this AD.

Operators should note that, for installation of dampers with part numbers other than 23700-5 or -7, they must submit a request for approval of an AMOC in accordance with paragraph (c) of this AD.

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 147 Model F.28 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the required replacement, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,910 per airplane. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $333,690, or $2,270 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 andthe 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 AmendmentAccordingly, 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.

Sec. 39.13 [Amended]

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