98-04-13: Propeller Low Torque Switch

98-04-13 Rolls-Royce Limited: Amendment 39-10325. Docket 94-ANE-43. Supersedes AD 90-08-12, Amendment 39-6473. Applicability: Rolls-Royce Limited (R-R) Dart Mk. 506, 510, 511 series, 514 series, 525 series, 526, 527, 528 series, 529 series, 530, 531, 532 series, 535 series, 542 series, 551 series, and 552 series turboprop engines, installed on but not limited to the following aircraft: Gulfstream Aerospace Corp. G-159, British Aerospace HS 748, Fokker Aircraft F.27, Mitsubishi Heavy Industries YS-11, General Dynamics (Convair) 580 and 600 series, and Vickers Armstrongs (Aircraft Limited) Viscount. Note 1: Rolls-Royce Limited engine models Mk. 515, 520, 533, 534, 536, and 543 were removed in this final rule from the NPRM as these engine models were not U.S.-validated. Note 2: Other changes to the final rule's applicability from the NPRM's applicability are as follows: Mk. 511 was changed to Mk. 511 series Mk. 514 was changed to Mk. 514 series Mk. 525 was changed to Mk.525 series Mk. 528 was changed to Mk. 528 series Mk. 529 was changed to Mk. 529 series Mk. 532 was changed to Mk. 532 series Mk. 535 was changed to Mk. 535 series Mk. 542 was changed to Mk. 542 series Mk. 551 was changed to Mk. 551 series Mk. 552 was changed to Mk. 552 series. Note 3: 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 (f) 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 cracking of the snap diaphragm in the propeller low torque switch, which could delay propeller auto-feathering and thereby adversely affect aircraft controllability, remove from service propeller low torque switch part numbers (P/N) 3700892, 3700895, 3701232, 3500355, 3500356, 3500410 through 3500412, L944707 through L944709, L944738 through L944740, L944742 through L944744, L944769, L944772, and L944774, in accordance with R-R Dart Aero Engines Service Bulletin (SB) No. Da61-12, Revision 2, dated September 1978, as follows: (a) Remove from service propeller low torque switches that have accumulated 5 or more calendar years time in service (TIS) on the effective date of this AD, within 30 days after the effective date of this AD, and replace with a serviceable part. (b) Remove from service propeller low torque switches that have accumulated less than 5 calendar years TIS on the effective date of this AD, within 5 calendar years total TIS, or within 30 days after the effective date of this AD, whichever occurs later, and replace with a serviceable part. (c) Remove from service propeller low torque switches that cannot have their in-service calendar time established within 30 days after the effective date of this AD, and replace with a serviceable part. (d) Thereafter, remove from service new or overhauled propeller low torque switches at or prior to accumulating 5 calendar years TIS since initial installation on an engine. This limit includes storage or on-shelf time accumulated after initial installation on an engine. Overhaul of the propeller low torque switch zero-times the part. (e) For the purpose of this AD, a serviceable part is defined as a new or overhauled propeller low torque switch with less than 5 calendar years TIS since first entry into service. (f) 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, Engine 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, Engine Certification Office. Note 4: Information concerning the existence of approved alternative method of compliance with this AD, if any, may be obtained from the Engine Certification Office. (g) 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 aircraft to a location where the requirements of this AD can be accomplished. (h) The actions required by this AD shall be done in accordance with the following R-R SB: Document No. Pages Revision Date Dart Aero Engines SB No. Da61-12 1-4 2 September 1978 5-6 Original May 1976 Total pages: 6. This incorporationby 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 plc, Attn.: Dart Engine Service Manager, East Kilbride, Glasgow G74 4PY, Scotland. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief 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. (i) This amendment becomes effective on March 24, 1998.