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Summary

Summary

What happened

Following a number of accidents and serious incidents involving Robinson R22 helicopters where a failure of either one or both rotor drive v-belts has led to the occurrence event, the Australian Transport Safety Bureau (ATSB) initiated a Safety Issues investigation into the broader question of Robinson R22 v-belt operational reliability.

What the ATSB found

There were no systemic safety issues identified as a result of the ATSB investigation. However, drive belt reliability was found to be negatively influenced by a broad range of operational and maintenance-related factors, including:

  • high gross or overweight operations
  • high or excessive engine power settings (manifold pressures)
  • sheave misalignment and/or poor drive system condition
  • inadequate or infrequent inspections of the rotor drive system.

What's been done as a result

In July 2011, the ATSB issued safety advisory notice AO-2011-060-SAN-001, reinforcing the need for continued vigilance by operators and maintenance organisations regarding the routine inspection of the R22 drive system.

During the course of this investigation, the Robinson Helicopter Company released an updated ‘Revision-Z’ v-belt. Since that change, R22 industry feedback has indicated an overall improvement in the stability of the drive system and a reduction in failure rates.

Safety message

The Robinson R22 helicopter is the most popular light utility helicopter used in Australia and has a reputation for being an extremely reliable machine. Owners and operators should fully appreciate the nature and effects of the operational stresses placed on the helicopter, particularly if the machine is utilised in a dynamic and demanding manner such as required for cattle mustering operations.

Pilots, operators and maintainers should pay particular attention to the installation and condition of R22 drive belts and other components of the drive system, and should ensure that the manufacturer’s requirements for inspection and maintenance of the drive system are adhered to at all times.

The continued safe flight of an R22 helicopter that has sustained a v-belt failure can be assisted by the pilot’s awareness of the indications of a drive system malfunction, and the appropriate management of the emergency autorotation in accordance with published procedures.

 
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