The Transportation Safety Board says there is no indication that mechanical problems were a factor in the fatal Ornge helicopter accident near Moosonee, Ont. last Friday.
The Ontario air ambulance went down shortly after take-off, killing two paramedics and two pilots.
The TSB investigator in charge, Daryl Collins, said his team was able to access information from the cockpit voice recorder but he did not provide any further details.
"What will happen now is the investigation team is going to be extensively looking at company procedure, still continuing to look at technical records as well, talking with the company and conducting numerous interviews,” he said.
Collins added investigators were able to obtain several other pieces of evidence from the crash site, which are expected to help in the investigation.
On Friday, Ornge confirmed the names of the four who died in the crash:
"Their lives were lost serving the public, and we owe a deep debt of gratitude," said Dr. Andrew McCallum, president and CEO of Ornge.
The helicopter, one of six Sikorsky S76 choppers in Ornge's fleet, was built in 1980 and was certified by Transport Canada, McCallum said at news conference Friday.
Ornge's five remaining S76 helicopters were taken out of service out of an "abundance of caution," he added.
But on Tuesday, Ornge announced it would return them to service after the TSB "did not raise concerns regarding the S76 fleet." The S76 helicopter is flown out of bases in Thunder Bay and Kenora.
Ornge said it is developing alternative plans to restore helicopter service in Mooseonee but, in the interim, fixed-wing aircraft is being used for patient transport in the James Bay region.
The TSB probe is expected to take a year to complete.