AD 99-17-09 Airworthiness Directives; Allison Engine Company, Inc AE 2100A and AE 2100C Series Turboprop Engines

Allison Engine Company, Inc. AE 2100A and AE 2100C series turboprop engines, installed on but not limited to SAAB 2000 series and Industri Pesawat Terbang Nusantara (IPTN) N-250 series aircraft. 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 (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.

Required as indicated, unless accomplished previously. To prevent propeller gearbox (PGB) and power section (P/S) strut fitting cracks, which could result in PGB misalignment, in-flight engine shutdown, and possible loss of the propeller, accomplish the following: (a) Perform initial and repetitive visual inspections of the PGB and P/S strut fittings for notches and cracks, and, if necessary, replace with serviceable parts, in accordance with Rolls-Royce Alert Service Bulletin (ASB) AE 2100A-A-72-193, also designated AE 2100C- A-72-143, Revision 1, dated October 20, 1998, as follows: (1) Perform the initial inspection within 100 hours time-in- service (TIS) after the effective date of this AD. Record findings in Table 1 at the end of the ASB to determine the inspection interval. (2) If parts are found cracked, prior to further flight, remove from service cracked propeller gearboxes or power section strut fittings and replace with serviceable parts. (3) If both strut fittings are found notched, thereafter inspect at intervals not to exceed 100 hours timein-service (TIS) since last inspection. (4) If one strut fitting is found notched, thereafter inspect at intervals not to exceed 400 hours TIS since last inspection. (5) If no parts are found cracked and neither strut fitting is found notched, no repetitive inspections are required, and rework the strut fittings in accordance with paragraph(b) of this AD. (b) Perform one of the following in accordance with Rolls-Royce ASB AE 2100A-A-72-197, also designated AE 2100CA-72-149, dated May 19, 1999: (1) Remove the old PGB and P/S strut fittings and install the new serviceable strut fittings in accordance with the strut fittings part number charts in paragraph (4) of the ASB. (2) Rework the existing parts within the schedule determined by the inspection results of paragraph (a) of this AD in accordance with the Rolls-Royce ASB AE 2100A-A-72-193, or AE 2100C-A-72-143, Revision 1, dated October 20, 1998, page 12, Table 1, entries in the ``Answer'' column, as follows: (i) If two ``Yes'' entries are contained in the ``Answer Column'', rework within the next 100 hour TIS after the inspection performed in accordance with paragraph (a) of this AD. (ii) If one ``Yes'' entry is contained in the ``Answer Column'', or there are no ``Yes'' entries in the ``Answer Column'' refer to Section 2 in Rolls-Royce ASB AE 2100A-A-72197, also designated AE 2100C-A-72-149, dated May 19, 1999, for the affected PGB and P/S strut fittings rework or replace instructions. (iii) Following completion of the rework, mark affected parts in accordance with the following configuration chart: ---------------------------------------------------------------------------------------------------------------- New P/N Name Old P/N QTY/ENG ---------------------------------------------------------------------------------------------------------------- 23071762................................. Fitting, Strut (RH), 23055218................... 1 Propeller Gearbox. 23071763................................. Fitting, Strut (LH), 23055217................... 1 Propeller Gearbox. 23071764................................. Fitting, Strut (RH), Power 23055228, 23057098......... 1 Section. 23071765................................. Fitting, Strut (LH), Power 23055229, 23057099......... 1 Section. ---------------------------------------------------------------------------------------------------------------- (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, Chicago Aircraft Certification Office. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Chicago Aircraft Certification Office. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Chicago Aircraft Certification Office. (d) Special flight permits may be issued in accordance with Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a [[Page 45423]] location where the inspection requirements of this AD can be accomplished. (e) The actions required by this AD shall be done in accordance with the following Rolls-Royce ASBs: ---------------------------------------------------------------------------------------------------------------- Document No. Pages Revision Date ---------------------------------------------------------------------------------------------------------------- AE 2100A-A-72-193/AE 2100C-A-72-143 1-12 1............................... October 20, 1998. Total pages: 12. ASB AE 2100A-A-72-197/AE 2100C-A-72- 1-25 Original........................ May 19, 1999. 149. Total pages: 25 ---------------------------------------------------------------------------------------------------------------- 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 Rolls-Royce Allison, P.O. Box 420, Speed Code R-01B, Indianapolis, IN 46202-0420; telephone (317) 230-2720, fax (317) 230-3381. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC. (f) This amendment becomes effective on September 7, 1999. Issued in Burlington, Massachusetts, on August 11, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 99-21330 Filed 8-19-99; 8:45 am] BILLING CODE 4910-13-U