97-13-05: Horizontal Stabilizer Control Unit (HSCU)

97-13-05 FOKKER: Amendment 39-10051. Docket 96-NM-154-AD. Applicability: Model F28 Mark 0100 series airplanes, as listed in Fokker Service Bulletin SBF100-27-069, dated January 1, 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 (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: Requiredas indicated, unless accomplished previously. To prevent failure of the lower bolts that join the dog-links to the piston of the horizontal stabilizer control unit (HSCU) because of stress corrosion cracking, which could result in loss of control of the horizontal stabilizer and reduced controllability of the airplane, accomplish the following: (a) Within 3 months after the effective date of this AD, loosen the nut [part number (P/N) MS17825-10] on each lower bolt (P/N 23233-1) that joins the dog-links to the piston of the HSCU, in accordance with Part 1 of the Accomplishment Instructions of Fokker Service Bulletin SBF100- 27-069, dated January 1, 1996, as revised by Part 1 of Fokker Service Bulletin Change Notification SBF100-27-069/01, dated January 8, 1996; and Part A of the Accomplishment Instructions of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated November 10, 1995. (b) Within 6 months after the effective date of this AD, inspect each lower bolt (P/N23233-1) that joins the dog-links to the pistons of the HSCU to detect cracking and failure, in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27- 069, dated January 1, 1996, as revised by Part 2 of Fokker Service Bulletin Change Notification SBF100-27-069/01, dated January 8, 1996; and Part B of the Accomplishment Instructions of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated November 10, 1995. (1) If no cracking or failure is detected, prior to further flight, apply corrosion protection to each bolt, and reassemble and reidentify the HSCU, in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-069, dated January 1, 1996, as revised by Part 2 of Fokker Service Bulletin Change Notification SBF100-27-069/01, dated January 8, 1996; and Part B of the Accomplishment Instructions of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated November 10, 1995. (2) If any cracking or failure is detected, prior to further flight, replace the discrepant bolt with a serviceable bolt, apply corrosion protection to each serviceable bolt, and reassemble and identify the HSCU, in accordance with Part 2 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-069, dated January 1, 1996, as revised by Part 2 of Fokker Service Bulletin Change Notification SBF100-27-069/01, dated January 8, 1996; and Part B of the Accomplishment Instructions of Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated November 10, 1995. (c) For airplanes having serial numbers 11500, 11505, and 11511: Within 6 months after the effective date of this AD, reidentify the HSCU in accordance with Part 3 of the Accomplishment Instructions of Fokker Service Bulletin SBF100-27-069, dated January 1, 1996. (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 2: Information concerning the existence of 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 SBF100-27-069, dated January 1, 1996, as revised by Fokker Service Bulletin Change Notification SBF100-27- 069/01, dated January 8, 1996; and Menasco Aerospace Ltd. Service Bulletin 23100-27-19, dated November 10, 1995. 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., Technical Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, 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. (g) This amendment becomes effective on August 1, 1997.