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The flying instructor advised that at 300 feet, after taking off to the north from the eastern grass at Moorabbin, he first heard an odd noise and then felt a violent vibration through the airframe. He also noticed that rotor RPM had begun to diminish. Immediately he lowered the collective, closed the throttle, and carried out an autorotation into an area just outside the airfield boundary. The engine continued to idle from the moment of closing the throttle. Engineers found that the aft bearing on the lower pulley assembly had disintegreated internally and the forward bearing was rough. (This pulley assembly is part of the drive train which transmits engine power to the main gearbox via eight rubber belts.) The bearing (part number 269A5050-78) which failed was lifed at 1800 hours. It failed at 741 hours total time in service and 246 hours since it was last inspected/greased. There was no evidence of lack of grease or overheating of the bearings. Significant Factor The following factor was considered relevant to the development of the incident: 1. The lower pulley aft bearing failed in flight.
Download Final Report
[ Download PDF: 17KB]
General details
Date: 02 July 1993 Investigation status: Completed 
Time: 12:33 EST  
 Investigation type: Occurrence Investigation 
 Occurrence type: Transmission and gearbox 
Release date: 26 October 1994 Occurrence class: Technical 
Report status: Final Occurrence category: Incident 
Aircraft details
Aircraft manufacturer: Hughes Helicopters 
Aircraft model: 269C 
Aircraft registration: VH-IHV 
Sector: Helicopter 
Damage to aircraft: Nil 
Departure point:Moorabbin VIC
Destination:Moorabbin VIC
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Last update 23 July 2015