"The investigators will make a preliminary assessment of the wreckage and will speak to witnesses, including the hunters who were on board and the pilot, once he has recovered from his injuries.
"The CAA would like to thank police and the RCCNZ (Rescue Co-ordination Centre New Zealand) who have provided preliminary information on the accident.
"We hope to give a further update on Thursday afternoon."
The pilot, who left from Franz Joseph, was flying an Alpine Adventurers Hughes 369 and a spokesman for the firm said the crash hit the helicopter community hard.
"It's quite a tight-knit fraternity anyway so whether people work for the same company or not, it's a tight industry down here.
"Everyone knows everyone so it certainly has an effect on everyone and gives everyone a fright," the spokesman said.
Two men from a hunting group had already been flown out when an unknown "mishap" occurred during the second trip's take off, he said.
A RCCNZ spokeswoman said the pilot and hunters were rescued about 12pm on Saturday.
The centre responded to two distress beacon activations and notification from the helicopter firm its chopper was overdue and should have returned by 9.30am, the spokeswoman said.
"As the RCCNZ was arranging for the Garden City Rescue helicopter from Greymouth to fly to the site it received information from the company about the problem at take-off and that three men were injured," she said.
"Another company helicopter had been flown to the glacier to check the situation and was able to pass on information about what had happened on the ground."
