The Australian Transport Safety Bureau encourages all operators of R22 helicopters, and organisations performing installation, inspection, and maintenance activities on the drive belts of R22 helicopters to note the circumstances detailed in this preliminary report. The ATSB reinforces the need for continued vigilance by operators and maintenance organisations during the routine inspection of the R22 drive system as follows:
- Drive belts. Check for defects or damage such as blistering, cracking or delamination.
- Drive sheaves. Check for incorrect alignment, poor sheave surface condition and/or uneven groove wear patterns.
- Clutch actuator. Check for incorrect tension, such as indicated by rotor engagement during engine start.
Attention is also drawn to the detrimental effect on drive belt life of exceeding engine horsepower limits, as measured by manifold air pressure (MAP). To mitigate that risk, pilots should operate the helicopter within the flight manual limits; specifically, those related to MAP.