98-08-19: Wing to Fuselage Attachment Brackets and Straps

98-08-19 TWIN COMMANDER AIRCRAFT CORPORATION: Amendment 39-10468; Docket No. 95-CE-92-AD. Applicability: Models 500, 500A, 500B, 500S, 500U, 520, 560, 560A, 560E, 560F, 680, 680E, 680F, 680FL, 680FLP, 680FP, 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B and 720 airplanes, all serial numbers, 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 (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 in the body of this AD after the effective date of this AD, unless already accomplished. To prevent cracks at the wing to fuselage attach points, which, if not detected and corrected, could cause structural failure and loss of control of the airplane, accomplish the following: (a) For all models except Models 520, 560, 690C and 695, accomplish the actions in the following table in accordance with the Compliance section and PART I, II, and III of the ACCOMPLISHMENT INSTRUCTIONS sections of Twin Commander Service Bulletin No. 223, dated October 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997: A B C PART I Upon the accumulation of 6,000 hours total time-in-service (TIS) or within the next 100 hours TIS, whichever occurs later, install access holes in left andright wing leading edges and inspect the forward attach brackets and straps for cracks. For any airplanes that have wings modified with titanium leading edges through an STC, remove the wing root farings to accomplish the required inspections, in lieu of installing the access holes. (Accomplish in accordance with PART I of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) If cracked, prior to further flight, replace the brackets and straps or repair the part by an approved repair scheme (see paragraph (b) of this AD). Then, accomplish PART II of this AD. (Accomplish in accordance with PART I of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) If no cracks are found, repeat inspection at 1,000 hour (hr.) intervals until cracks arefound, replace the cracked part or repair by an approved repair scheme (see paragraph (b) of this AD), then accomplish PART II. (Accomplish in accordance with PART I of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) PART II Inspect for cracks at the wing leading edge close-outs, upper & lower return flange radius, fuselage frame where tee bracket attaches, inboard side of attach bracket and frame tee bracket. (Accomplish in accordance with PART II of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997, and Revision Notice No. 2, dated August 18, 1997.) If cracked, prior to further flight, replace any cracked part or repair the part with an approved repair scheme (see paragraph (b) of this AD). If no cracks are found, continue to repetitively inspect at 1,000 hour TIS intervals. (Accomplish in accordance with PART II of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) After repair or replacement is accomplished, continue to inspect at 6,000 hr. intervals. (Accomplish in accordance with PART II of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) PART III For pressurized airplanes, at 6,000 hr. total TIS or within the next 100 hours TIS whichever occurs later, inspect fuselage station (F.S.) 100 for cracks. For non-pressurized airplanes, at 12,000 hr. total TIS or within the next 100 hours TIS whichever occurs later, inspect F.S. 100 for cracks. (Accomplish in accordance with PART III of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No.1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) If cracked, prior to further flight, repair with an approved repair scheme (see paragraph (b) of this AD), and continue to inspect at 1,000 hr. intervals. (Accomplish in accordance with PART III of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) If no cracks, repeat inspection at 1,000 hr. intervals until cracks are found, then accomplish PART III B of this AD. (Accomplish in accordance with PART III of Compliance Section in Twin Commander SB 223, dated Oct. 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997.) (b) Obtain an FAA-approved repair scheme from the manufacturer through the Manager of the Seattle Aircraft Certification Office at the address specified in paragraph (f) of this AD. (c) For Twin Commander Models 520 and 560 airplanes, upon the accumulation of 6,000 hours total TIS or within the next 100 hours TIS, whichever occurs later, accomplish PART II of the table in paragraph (a) of this AD. Accomplish PART III in accordance with the compliance times in the above table of paragraph (a). These models are excluded from the wing leading edge access hole installation in PART I of the table in paragraph (a) of this AD. (d) For Twin Commander Models 690C and 695 airplanes, accomplish PARTS I and II in accordance with the compliance times in the above table of paragraph (a). These Models are excluded from PART III of the table in paragraph (a) of this AD. (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) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Seattle Aircraft Certification Office, 1601 Lind Ave. S.W., Renton, Washington, 98055-4056. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Seattle Aircraft Certification Office. NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle Aircraft Certification Office. (g) The inspections and installations required by this AD shall be done in accordance with the Twin Commander Service Bulletin No. 223, dated October 24, 1996 as amended by Revision Notice No. 1, dated May 8, 1997 and Revision Notice No. 2, dated August 18, 1997. 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 Twin Commander Aircraft Corporation, P.O. Box 3369, Arlington, Washington, 98223. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC. (h) This amendment becomes effective on May 18, 1998.