81-24-03: Engine Power Loss Prevention

81-24-03 GULFSTREAM AMERICAN CORPORATION: Amendment 39-4257. Applies to Model AA5, Serial Numbers AA5-0641 through AA5-0834; Model AA5A, Serial Numbers AA5A-0001 through AA5A-0900; Model AA5B, Serial Numbers AA5B-0001 through AA5B- 1323, airplanes certificated in all categories. Compliance required as indicated, unless already accomplished. To prevent an engine power loss, accomplish the following: PART I For Model AA5 Serial Numbers AA5-0641 through AA5-0834; Model AA5A Serial Numbers AA5A-0001 through AA5A-0900, accomplish the following: For airplanes with 400 or more hours time in service on the effective date of this AD, comply with paragraphs (a) and (c) within 25 hours time in service from the effective date of this AD. Thereafter comply with paragraph (a) at intervals not to exceed 25 hours time in service from the last inspection until paragraph (b) has been accomplished and with paragraph (d) within the next 50 hours time in service from the effectivedate of this AD. For airplanes with less than 400 hours time in service on the effective date of this AD, comply with paragraph (d) within the next 50 hours time in service from the effective date of this AD and with paragraphs (a) and (c) prior to the accumulation of 425 hours total time in service. Thereafter comply with paragraph (a) at intervals not to exceed 25 hours time in service from the last inspection until paragraph (b) has been accomplished. (a) Inspect both forward and aft carburetor airbox screens (Gulfstream American P/N 5503006-9) to determine if any of the wires are broken. (1) If there are less than five broken wires per screen, inspect the induction system and the carburetor throat for filter material and correct, if necessary. Comply with paragraph (b) within 50 hours time in service from the first inspection under this paragraph. (2) If there are five or more broken wires per screen, inspect the induction system and the carburetor throat forfilter material and correct, if necessary. Comply with paragraph (b) before further flight. (b) Install the improved filter retention screens (Gulfstream American P/N 5503006- 20). (c) Inspect the carburetor airbox for damage and the carburetor air filter for deterioration. (1) If the airbox is found to have cracks, or loose or missing fasteners, replace or repair, as necessary, before further flight. (2) If the air filter is found to be separated and/or deteriorated, replace with an appropriate serviceable filter before further flight. (d) Within the next 50 hours time in service from the effective date of the AD, install a permanent warning placard, Gulfstream P/N 5503014, on exterior of the airbox which reads: "WARNING Air Filter deterioration can cause engine power loss. Consult Aircraft Maintenance Manual for air filter servicing and replacement requirements." Part II For Model AA5B, Serial Numbers AA5B-0001 through AA5B-1323, accomplishthe following: For airplanes with 400 or more hours time in service on the effective date of this AD, comply with paragraph (a) within 25 hours time in service from the effective date of this AD. For airplanes with less time than 400 hours time in service on the effective date of this AD, comply with paragraph (a) prior to the accumulation of 425 hours time in service. (a) Inspect the carburetor airbox for damage and the carburetor air filter for deterioration. (1) If the airbox is found to have cracks, or loose or missing fasteners, replace or repair, as necessary, before further flight. (2) If the air filter is found to be separated and/or deteriorated, replace with an appropriate serviceable filter before further flight. (b) Within the next 50 hours time in service from the effective date of the AD, install a permanent warning placard, Gulfstream P/N 5503014, on exterior of the airbox which reads: "WARNING Air Filter deterioration can cause enginepower loss. Consult Aircraft Maintenance Manual for air filter servicing and replacement requirements." An equivalent method of compliance may be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Southern Region. The airplane may be flown in accordance with FAR 21.197 and FAR 21.199 to a base where these repairs and/or replacements can be performed. Make the appropriate maintenance record entry for Parts I and II. Gulfstream American Service Bulletin No. 170 dated July 23, 1981, pertains to Part I of this AD. Gulfstream American Service Letter No. 81-1 dated October 9, 1981, pertains to Part II of this AD. This amendment becomes effective November 16, 1981.