Airworthiness Directive · Amendment 39-10233 · Allison Engine Company Model 250-C40B Turboshaft Engines
Allison Engine Company Model 250-C40B Turboshaft Engines
Allison Engine Company Model 250-C40B turboshaft engines, with engines, gearboxes, and gears identified by serial number (S/N) in Allison Alert Commercial Engine Bulletin (CEB) No. A-72-5009, dated May 21, 1997. The 250-C40B engine is installed on and limited to the twin-engine Bell Helicopter Textron 430 series helicopters.
This amendment adopts a new airworthiness directive (AD) that is applicable to Allison Engine Company Model 250-C40B turboshaft engines. This action requires installation of a placard requiring pilots to record torque level and time in service operating above 86% engine torque until the defective parts have been replaced, no later than December 31, 2000, or when certain maintenance actions are accomplished, or when certain operational restrictions are exceeded, whichever occurs earliest. This amendment is prompted by a report from Allison Engine Company of a manufacturing defect in certain helical power takeoff gearshaft assemblies, identified by serial numbers. The actions specified in this AD are intended to prevent fatigue failure of the helical power takeoff gearshaft assembly, which could result in a loss of engine power and inflight engine shutdown.
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
