83-07-20: Exhaust System

83-07-20 SIAI-MARCHETTI: Amendment 39-4622. Applies to Model S205-22R airplanes with a muffler assembly P/N 870-8 or P/N 870-9 installed, certificated in any category. Compliance: Required as indicated unless already accomplished. To prevent failure of the exhaust system, accomplish the following: (a) Within the next 100 hours time-in-service after the effective date of this AD or when the muffler has accumulated 500 hours time-in-service, whichever occurs later, and at each 100-hour time-in-service interval thereafter, accomplish the following: (1) Perform a fiberscope inspection of the inside baffling of the muffler assembly for cracks by inserting an OLYMPUS ILK-2 type fiberscope (or equivalent) though the exhaust tube into the inside baffling of the muffler assembly in accordance with the "INSTRUCTION" section of SIAI-Marchetti Service Bulletin No. 205B56 dated November 20, 1981, or an FAA-approved equivalent. (i) If cracks are found, prior to further flight, replace the muffler. (ii) If no cracks are found, continue the repetitive inspections as indicated above. (b) The intervals between the repetitive inspections required by this AD may be adjusted up to 10 percent of the specified interval to allow accomplishing these inspections concurrent with other scheduled maintenance of the airplane. (c) Operators who have not kept records of hours time-in-service of the mufflers must substitute airplane hours time-in-service in lieu thereof. (d) Airplane may be flown in accordance with FAR 21.197 to a location where this AD can be accomplished. (e) An equivalent method of compliance with this AD, if used, must be approved by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium. This amendment becomes effective on April 14, 1983.