On 9 May 2011, the pilot of a Robinson Helicopter Company R22 Beta II helicopter, registered VH-DSD, was conducting mustering operations 83km north-west of Julia Creek, Queensland. The helicopter was operating in close proximity to the ground when drive to the rotor system was lost resulting in a high rate of descent at the point of impact. The pilot was fatally injured.
What the ATSB found
The ATSB found that the two v-belts that transfer torque from the engine to the rotor system had failed. The damage to the forward v-belt indicated that it had partially dislodged from the drive sheave, resulting in significant damage to the belt. At some point the v-belt fragmented, compromising the redundancy of the belt-drive system. Once the rear v-belt failed, all drive to the rotors was lost.
As a result of the drive failure and operating conditions at the time, the pilot was faced with the need to conduct an autorotative landing from a low altitude and at minimal speed. As a consequence, there was limited time for the pilot to recognise the condition, respond accordingly, and for the autorotation to develop. This situation resulted in a high rate of descent at the point of impact.
What has been done as a result
Although no organisational or systemic issues that might adversely affect the future of aviation operations were identified, the importance of the correct installation and maintenance of the drive system and v-belts in R22 helicopters, and their operation within the stipulated power limits was reaffirmed. ATSB safety advisory notice AO-2011-060-SAN-001, which was issued as part of the preliminary factual report into this occurrence, reinforced the need for continued vigilance by operators and maintenance organisations regarding the routine inspection of the R22 drive system.
Pilots and operators should pay particular attention to the installation, maintenance, and inspection of R22 drive belts and other components of the helicopter’s drive system. In the event of an aircraft malfunction, pilot proficiency in emergency situations and particularly autorotations is especially important.
Preliminary report released 6 July 2011
On 9 May 2011 a Robinson Helicopter Company R22 Beta II helicopter (R22), registered VH-DSD (DSD), was conducting mustering operations about 85 km north-west of Julia Creek, Queensland in conjunction with another R22 helicopter. A third R22 was operating independently about 15 km away. At about 1445 Eastern Standard Time, the pilot of DSD made a radio transmission indicating that a problem had occurred and that he was unable to continue flying.
The other pilots flew to the area and discovered the wreckage of DSD and that the pilot, the sole occupant had been fatally injured.
Examination of the wreckage revealed that a drive belt had broken. Two belt fragments were found about 60 m from the main wreckage.
Although the circumstances of the accident are still under investigation, the Australian Transport Safety Bureau has, in the interest of transport safety, issued a Safety Advisory Notice stressing the need for continued vigilance by operators and maintenance organisations during the routine inspection of the R22 helicopter's drive system. The attention of pilots is also drawn to the requirement to operate the helicopter within the flight manual limits; specifically, those related to manifold air pressure.
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|Date:||09 May 2011||Investigation status:||Completed|
|Time:||1440 EST||Investigation level:||Complex - click for an explanation of investigation levels|
|Location:||85 km NW of Julia Creek|
|State:||Queensland||Occurrence type:||Transmission and gearbox|
|Release date:||06 December 2012||Occurrence class:||Technical|
|Report status:||Final||Occurrence category:||Accident|
|Highest injury level:||Fatal|
|Aircraft manufacturer||Robinson Helicopter Co|
|Type of operation||Aerial Work|
|Damage to aircraft||Serious|