Airworthiness Directive · Amendment 39-9749 · Allison 250 Series Turbine Engines
Allison 250 Series Turbine Engines
Allison Model 250-B15G,-B17F, -B17F/1, -B17F/2, - C20, -C20B, -C20F, -C20J, -C20S, -C20W, -R, -C20R/1, -C20R/2, -C20R/ 4, -C28B, -C28C, -C30, -C30P, -C30M, and -C30G turbine engines, with Superior Air Parts, Inc. Parts Manufacture Approval (PMA) bearings, Part Number (P/N) A6871505 and P/N A23007152, installed. These engines are installed on but not limited to the following aircraft: Aerospace Technologies of Australia PTY Ltd. N-22 and N-24; Agusta S.p.A A109 series, SF600 series; Beech Aircraft Corp. A36 and T34 (Tradewind Turbines conversion); Bell Helicopter Textron Model 47 (Soloy Conversion), OH58 series, 206 series, 230, 430; Cessna 206 and 207 (Soloy Conversions); Enstrom Helicopter Corp. TH28, 480; Eurocopter Deutschland GmbH BO105 series; Eurocopter France AS355 series; Flugzeugwerke Altenrheim AG (FFA) AS202 series; Hiller Aviation UH12 series (Soloy Conversions); Maule Aerospace Technology Corp. MX-7 series; McDonnell Douglas Helicopter Co. OH6 series, 500 series, MD500 series, MD520N series, MD530 series; Partenavia Costruzioni Aeronautiche S.p.A P68 series; Pilatus Britten-Norman Ltd. BN-2T; and Sikorsky Aircraft Division S76 series. Note: 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 (e) 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.
This amendment adopts a new airworthiness directive (AD) that is applicable to Allison 250 series turbine engines. This action requires initial and repetitive visual inspections of all engine filters for metal particles resulting from premature wear of two bearings produced under Parts Manufacture Approval (PMA) by Superior Air Parts, Inc. In addition, this AD requires replacement of those bearings with bearings that incorporate improved retainers, which constitutes terminating action to the inspection requirements of this AD. This amendment is prompted by a report of a failure during a ground test of an engine with bearings manufactured by Superior Air Parts, Inc. The actions specified in this AD are intended to prevent bearing failure due to bearing separator instability, which can result in subsequent turbine and engine failure.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Engines
