The Plan
The plan was for two lifts 1. mast 2. crown.
Line was Spectra SK75 12mm MBL 17900kgs
Length 30m (as selected by pilot)
Mast lifted to vertical then crew pin base and rig 3 temporary cables and tension. call clear to pilot.
Pilot to release line from top. if failure to release.
1. pull up chopper and load the line. the mast was secure so no problem
2. Two riggers had to go to top of mast to receive second lift anyway so they were to release manually.
3. bring helicopter down to a hover and ground release.
once clear called pilot descended. radio comms between pilot and his spotter no call to rigger( guy under chopper).
As per plan this was condition 3, no radio calls made to indicate a change to this.
Pilot appears to have released the hook as the rigger had hold of it. Should require 5kgs force to release.
rigger under machine had worst location for judging clearance. Relying on pilot and spotter for call on that.
Rigger experience approx 1500 sling loads various machines. approx 2000hrs working with helicopters as loader driver and rigging installations. 47hrs flight training 12hrs pilot in command. lots of hours ferry flights.
CAA preliminary report.
time of accident wrong
line used wrong
height of mast wrong
no mention of spotter
no mention of agreed plan
never interviewed rigger, or any of the 8 crew in the zone that day
hope this helps with the conversation