97-24-02: Underfloor Pressure Bulkhead of Fuselage

97-24-02 BOMBARDIER, INC.: Amendment 39-10209. Docket 97-NM-285-AD. Applicability: Model CL-600-1A11 (CL-600) series airplanes, serial numbers 1004 through 1085 inclusive; Model CL-600-2A12 (CL-601) series airplanes, serial numbers 3001 through 3066 inclusive; Model CL-600-2B16 (CL-601-3A/-3R) series airplanes, serial numbers 5001 through 5194 inclusive; Model CL-600-2B16 (CL-604) series airplanes, serial numbers 5301 through 5352 inclusive; 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 (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 detect and correct fatigue cracking in the underfloor pressure bulkhead of the fuselage, which could result in uncontrolled depressurization of the airplane and/or reduced structural integrity of the fuselage, accomplish the following: (a) For Model CL-600-1A11 (CL-600) airplanes: Prior to the accumulation of 1,900 total landings, or within 100 landings after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracks at frame station (FS) 409 of the bulkhead web [part number (P/N) 600-32014-71/-95/-105], in accordance with Canadair Challenger Service Bulletin 600-0679, dated September 12, 1997. (1) If no crack is detected, repeat the detailed visual inspection thereafter at intervals not to exceed 600 landings. (2) If any crack is detected and if all three of the conditions specified in paragraphs (a)(2)(i), (a)(2)(ii), and (a)(2)(iii) of this AD are met, within 600 landings or 12 months after the crack is detected, whichever occurs first, repair the cracking in accordance with a method approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Until the repair is accomplished, repeat the detailed visual inspection at intervals not to exceed 100 landings. (i) No more than one crack exists at each corner radius, as specified in the service bulletin; and (ii) No crack extends under the angles having P/N 600-32014-13 and P/N 600-32014-15 on the aft side of the bulkhead web; and (iii) No crack exists in angles having P/N 600-32014-13 and P/N 600-32014-15 on the aft side of the bulkhead web. (3) If any cracking other than that identified in paragraph (a)(2) of this AD is detected, prior to further flight, repair it in accordance with a method approved by the Manager, New York ACO. (b) For Model CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A/-3R), and CL-600-2B16 (CL-604) series airplanes: Prior to the accumulation of 1,100 total landings, or within 100 landings after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracks at FS 409 of the bulkhead web (P/N 600-32014-105/-137), in accordance with Canadair Challenger Service Bulletin 601-0501, dated September 12, 1997 [for Model CL-600-2A12 (CL-601) and CL-600-2B16 (CL-601-3A/-3R) series airplanes); or Canadair Challenger Service Bulletin 604-53-007, dated September 30, 1997 [for Model CL-600-2B16 (CL-604) series airplanes]; as applicable. (1) If no crack is detected, repeat the detailed visual inspection thereafter at intervals not to exceed 600 landings. (2) If any crack is detected and if allthree of the conditions specified in paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii) of this AD are met, within 600 landings or 12 months after the crack is detected, whichever occurs first, repair the cracking in accordance with a method approved by the Manager, New York ACO. Until the repair is accomplished, repeat the detailed visual inspection at intervals not to exceed 100 landings. (i) No more than one crack exists at each corner radius, as specified in the service bulletin; and (ii) No crack extends under the angles having P/N 600-32014-113 and P/N 600-32014-115 on the aft side of the bulkhead web; and (iii) No crack exists in angles having P/N 600-32014-113 and P/N 600-32014-115 on the aft side of the bulkhead web. (3) If any cracking other than that identified in paragraph (b)(2) of this AD is detected, prior to further flight, repair it in accordance with a method approved by the Manager, New York ACO. (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 ACO. 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. (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. (e) The inspections shall be done in accordance with Canadair Challenger Service Bulletin 600-0679, dated September 12, 1997; Canadair Challenger Service Bulletin 601-0501, dated September 12, 1997; or Canadair Challenger Service Bulletin 604-53-007, dated September 30, 1997; 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 Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, 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-97-16, dated September 25, 1997. (f) This amendment becomes effective on December 3, 1997.