VANCOUVER -- A final report into a fatal 2020 helicopter crash concluded that the cause of the incident in Northern B.C. will never be determined for certain.

The Transportation Safety Board of Canada was tasked with investigating the death of a pilot on Aug. 17 in a crash near a mine about 250 kilometres north of Stewart.

The helicopter went down near the Eskay Creek Mine in an area accessible by air only.

The pilot was the only person on board, and died as a result of the crash.

In its report, the TSB says the pilot of the Aberdeen Helicopters Ltd. Airbus AS 350 B2 helicopter had been tasked with flying a day shift crew to their drilling sites on Nickel Mountain, and bringing the night crew back to camp.

The board's review says the pilot, who was not publicly identified by the TSB, picked up two more workers from camp and brought them to a worksite, refuelled and prepared for their next task: moving a dismantled drill rig to another area using a longline.

During this process, the TSB said, the weather began to worsen. It is not clear what the pilot had planned, but as heavy rain started to fall, the aircraft accelerated and rose into the air and started to turn, GPS data suggests. Then it crashed into a steep slope on the side of the mountain.

The pilot's injuries have not been detailed, but they did not survive. The helicopter caught fire on impact and was destroyed.

Later, workers tried to contact the pilot by radio. They searched the area, and another pilot working on the project helped search the area by air.

Poor weather conditions hampered the search, but eventually the wreckage was found. The pilot of the other company helicopter reported that the crash was not survivable.

The TSB looked into what information was available on the incident, and wrote in the report released Tuesday that the aircraft was built in 1996, but there was no indication of any deficiencies or issues.

It was equipped with an emergency locater transmitter, but strangely, no signal was detected by the other helicopter. Because the aircraft was destroyed in the crash, it is not known why the signal wasn't sent out.

The wreckage was examined, and there was nothing to suggest an airframe failure or malfunction had occurred, the TSB said.

The pilot had a proper licence and had accumulated more than 2,800 flight hours, the TSB said. At least 900 of those hours were on that type of helicopter, and more than 200 were on the specific aircraft he was flying at the time of the crash.

It was his second summer flying in the area and working with the exploration company, the board's report said.

The pilot had also completed an annual training program for low-visibility flight. And fatigue is not considered to be a factor based on his work and rest schedule.

While weather was a factor in the job the pilot was trying to complete, the forecast data for the area was limited.

The TSB could not determine whether the pilot had looked online for information on the conditions before his flight. Generally, this type of information is passed on between day and night crews, as the nearest weather stations are some distance from the site itself.

Rain on the windshield may have caused poor visibility and refraction errors, meaning it's possible the pilot couldn't properly see the horizon or the mountainside.

But ultimately, the report says, "an investigation may never be able to determine the exact causes and contributing factors," as there were no survivors or witnesses, and no on-board recording devices.