Investigation number
198801393
Occurrence date
Location
Grass Tree Hill (11 km NW of Cambridge)
Report release date
Report status
Final
Investigation type
Occurrence Investigation
Investigation status
Completed
Aviation occurrence category
Miscellaneous - Other
Occurrence class
Accident
Highest injury level
None

The pilot and the helicopter were involved in a training exercise for trainee fireman. The task was to teach safety around helicopters, especially relating to fire fighting activities. The State Fire Commission provided new sling equipment, purchased from a ship chandler. Experienced fire fighting personnel had prepared several sling loads in advance for the pilot. The strop chosen to lift the 500kg water bladder was 20 metres long. The purpose of the long strop was to enable the helicopter to lower the water bladder to firemen working in low scrub. The strop had been assembled by passing each end of the rope around a metal eyelet and whipping it because the polyester rope was not suitable for splicing. Visually the whipped ends looked satisfactory.

The helicopter lifted the load to about 150 feet above the ground and was accelerating through about 20 knots when the pilot heard a loud bang, felt a vibration through the airframe and realised that the load had detached from the helicopter. He made a precautionary landing nearby. The rope of the strop had slipped through the whipped section at the eyelet where it attached to the water bladder with a shackle. The rope had recoiled, damaged one of the three main rotor blades, ripped the right hand horizontal stabilizer and wrapped around the tail boom.

The known safe working load limits for the individual items comprising the strop were more than adequate for the intended sling loads. The new strop had never been proof tested; nor was there any indication that the helicopter company or the Fire Commission had instructed the manufacturer to proof test the strops.

Aircraft Details
Manufacturer
Aerospatiale Industries
Model
AS350
Registration
VH-AFO
Serial number
1105
Operation type
Aerial Work
Sector
Helicopter
Departure point
Grass Tree Hill TAS
Departure time
1113
Destination
Grass Tree Hill TAS
Damage
Substantial