AD 96-26-05

This amendment adopts a new airworthiness directive (AD), applicable to all Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes, that requires an inspection to detect cracking of the torque tube assembly of the left-hand (LH) elevator and surrounding structure; and to detect loose or sheared rivets in that assembly. This amendment also requires either replacement or repair of discrepant parts, as appropriate. This amendment is prompted by a report of fatigue cracking found on the torque tube support of the LH elevator. The actions specified by this AD are intended to ensure that cracking is detected and corrected in a timely manner so as to prevent failure of the torque tube or its support structure, which could result in reduced controllability of the airplane.

Final rule

96-26-05 FOKKER: Amendment 39-9869. Docket 96-NM-88-AD.
Applicability: All Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 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 (d) 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 ensure that cracking is detected and corrected in a timely manner so as to prevent failure of the torque tube of the left-hand (LH) elevator or its support structure, which could result in reduced controllability of the airplane, accomplish the following:

(a) Prior to the accumulation of 45,000 total flight cycles, or within 4 months after the effective date of this AD, whichever occurs later, perform an inspection to detect cracking of the torque tube assembly and the surrounding structure of the LH elevator, and to detect any loose or sheared rivets of that assembly, in accordance with "Part 1" of the Accomplishment Instructions of Fokker Service Bulletin F27/55-66, dated December 21, 1994.

(b) If no cracking is detected, and if no loose or sheared rivet is detected, during the inspection required by paragraph (a) of this AD: No further action is required by this AD.

(c) If any discrepancy is detected during the inspection required by paragraph (a) of this AD: Accomplish the applicable requirements of paragraph (c)(1), (c)(2), or (c)(3) of this AD at the time specified in that paragraph, and in accordance with Fokker Service Bulletin F27/55-66, dated December 21, 1994.

(1) If any cracking of the torque tube is detected, or if any loose or sheared rivet is detected: Prior to further flight, replace the discrepant part(s) in accordance with "Part 2," paragraph A., of the Accomplishment Instructions of the service bulletin.

NOTE 2: Fokker Service Bulletin F27/55-66 references Fokker Service Bulletin F27/55-40 as an additional source of service information for procedures to replace the torque tube assembly with a serviceable assembly.

(2) If any cracking of the rib at station 300 is detected: Prior to further flight, repair in accordance with "Part 2," paragraph B., of the Accomplishment Instructions of the service bulletin.

(3) If any cracking in the torque tube support is detected: Prior to further flight, accomplishthe requirements of either paragraph (c)(3)(i) or (c)(3)(ii) of this AD, as applicable.

(i) If the crack length does not exceed 30 mm, stop drill the crack and, thereafter, repeat the inspection specified in paragraph (a) of this AD at intervals not to exceed 50 flight hours, in accordance with "Part 2," paragraph C., of the Accomplishment Instructions of the service bulletin.

(ii) If the crack length exceeds 30 mm, repair in accordance with a method approved by the Manager, Standardization Branch, ANM-113.

(d) 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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 3: Information concerning the existenceof approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) 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.

(f) The actions shall be done in accordance with Fokker Service Bulletin F27/55-56, dated December 21, 1994. 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 Aircraft USA, Inc., 1199 North Fairfax Street, Alexandria, Virginia 22314. 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.

(g) This amendment becomes effective on February 12, 1997.

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 F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes was published in the Federal Register on September 13, 1996 (61 FR 48439). That action proposed to require a one-time inspection to detect fatigue cracking of the torque tube of the left-hand (LH) elevator and its surrounding structure, and repair, if necessary. That action also proposed to require an inspection to detect loose or sheared rivets of the same torque tube assembly, and replacement with serviceable rivets, if necessary.

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 theadoption of the rule as proposed.

Cost Impact
The FAA estimates that 34 Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $8,160, or $240 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.

Should an operator be required to replace the torque tube assembly of the LH elevator, the FAA estimates that it will take approximately 2 work hours per airplane to accomplish, and that the average labor rate is $60 per work hour. Replacement of the assembly will cost approximately $1,500 per airplane. Based on these figures, the cost impact of the replacement is estimated to be $1,620 per airplane.

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 FlexibilityAct. 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: