2000-09-05: Cone Shafts

2000-09-05 Allison Engine Company: Amendment 39-11714; Docket 99-NE-46-AD. Applicability: Allison Engine Company Models AE 3007A, AE 3007A1, AE 3007A1/1, AE 3007A1/2, AE 3007A1/3, AE 3007A1P, and AE 3007C turbofan engines, with cone shafts, part numbers (P/Ns) 23050728 and 23070729, installed. These engines are installed on but not limited to EMBRAER EMB-135 and EMB-145 series and Cessna 750 (Citation X) series airplanes. Note 1: This airworthiness directive (AD) applies to each engine 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 engines 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 (h) 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 prevent low cycle fatigue failure of cone shafts, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following: Removal from Service (a) For Allison Engine Company model AE 3007A engines, remove cone shafts from service prior to accumulating 9,500 cycles-since-new (CSN) and replace with serviceable parts. (b) For Allison Engine Company model AE 3007C engines, remove cone shafts from service prior to accumulating 14,500 CSN and replace with serviceable parts. (c) For Allison Engine Company models AE 3007A1, AE 3007A1/1, and AE 3007A1/2 engines, remove cone shafts from service prior to accumulating 7,500 CSN and replace with serviceable parts. (d) For Allison Engine Company model AE 3007A1/3 engines, remove cone shafts from service prior to accumulating 3,500 CSN and replace with serviceable parts. (e) For Allison Engine Company model AE 3007A1P engines, remove cone shafts from service prior to accumulating 2,400 CSN and replace with serviceable parts. New Life Limits (f) Paragraphs (a), (b), (c), (d) and (e) of this AD establish new, lower life limits for cone shafts, P/Ns 23050728 and 23070729. (g) Except for the provisions of paragraph (h) of this AD, no cone shafts, P/Ns 23050728 and 23070729, may remain in service exceeding the life limits established in paragraphs (a), (b), (c), (d) and (e) of this AD. Alternative Method of Compliance (h) 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, Chicago Aircraft Certification Office (ACO). Operators shall submit their requests through an appropriate FAA Principal MaintenanceInspector, who may add comments and then send it to the Manager, Chicago ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Chicago ACO. Ferry Flights (i) No special flight permits will be issued. Effective Date (j) This amendment becomes effective on July 5, 2000.