Engine failure - 28 km west-south-west of Warialda, New South Wales, on 2 February 2007, VH-HRT, Bell 407

Interim Factual report released 18 September 2007

On 2 February 2007, at about 1530 Eastern Daylight-saving Time, a Bell Helicopter Company model 407 (B407) medical helicopter with a pilot, a crewman, a doctor and a paramedic on board departed Tamworth, NSW enroute to a car accident. At about 1610, the pilot broadcast on both the area and common traffic advisory frequency (CTAF) radio frequencies that they were inbound to Warialda at 28 km south-west and on descent from 6,500 ft above mean sea level. The pilot later reported that soon after the broadcast, the engine chip detector advisory capsule illuminated on the master caution panel. He reported that approximately 5 seconds later, he heard a loud noise, and the helicopter developed a severe high frequency vibration with a complete loss of engine power. The pilot then broadcast a distress advisory on the area and CTAF frequencies with position, altitude, passenger information and the problem. During the ensuing autorotation emergency landing, the helicopter landed heavily and rolled onto its side. None of the occupants were injured, but the helicopter was destroyed. The investigation determined that the engine sustained an in-flight catastrophic failure of the engine accessory gearbox. The failure of the gearbox was determined to be a fracture and separation of a section of the helical torquemeter gear, which resulted in complete loss of engine power.

On 2 February 2007, at about 1530 Eastern Daylight-saving Time, a Bell Helicopter 407 (407) emergency medical helicopter with a pilot, a crewman, a doctor and a paramedic on board departed Tamworth, NSW enroute to a car accident. At about 1610, the pilot broadcast on both the area and common traffic advisory frequency (CTAF) radio frequencies that they were inbound to Warialda at 28 km south-west and on descent from 6,500 ft [above mean sea level].

The pilot later reported that soon after the broadcast, the engine chip detector advisory capsule illuminated on the master caution panel. He reported that approximately 5 seconds later, he heard a loud noise, and the helicopter developed a severe high frequency vibration with a complete loss of engine power. The pilot then broadcast a distress advisory on the area frequency with position, altitude, passenger information and the problem. During the subsequent autorotation emergency landing, the helicopter landed heavily and rolled onto its side. None of the occupants were injured, but the helicopter was seriously damaged.

The investigation determined that the engine sustained an in-flight catastrophic failure of the engine gearbox. The gearbox failure was due to the fracture and separation of a section of the helical torquemeter gear, which resulted in the complete loss of engine power.