An Australian base jumper who watched Alan McCandlish fall to his death says the New Zealander was in "hardcore mode" in a new suit he had not practised making tight turns with.
Mr McCandlish died while base jumping in the Berner Oberland mountain region of Switzerland, on Saturday.
Swiss police said he hit a ledge, plunged over a cliff and fell on to another ledge.
Professional Australian base jumper Chris McDougall - who has also watched his girlfriend fall to her death when her parachute did not open during her 200th jump - this week posted on an online forum his personal account of watching Mr McCandlish fall to his death.
"I was expecting him to fly out from the other side of the ledge but instead there was a very distinct sound of an impact," he said.
Mr McCandlish had only just switched to a new wingsuit, which he was having difficulty with because of its different style of flying.
He had made about 12 jumps in the new suit, but had not practised turning sharply.
"Myself and Benny [a base jumper also at the scene] think that as he was flying so well on this jump that he went back into hardcore mode and decided to fly a tight line to the right.
"He was higher than most people who fly this line and we think he was trying to get over a large ledge that was also wide.
"We think he realised at the last second that he wasn't going to make it over and he initiated a fairly sharp turn to miss the ledge.
'We think that after the initial and fatal impact he either slid or rolled down this ledge and back into free fall and it was this time when we all heard and saw the impacting down to where he came to rest on the ledge."
Mr McDougall said the weather conditions on the day of the accident were perfect.
He shook Mr McCandlish's hand and told him to "have a good one" prior to the fatal jump.
Mr McCandlish's father, Richard, earlier this week said his eldest son loved the outdoors and adventure sports.
"He was a really active guy ... loved anything extreme. But base jumping was his passion ... In 2008, he and some mates pioneered the Kaipo Wall in Fiordland. They were the first ones to do that."
The Te Awamutu man said he and wife, Sue, last spoke to their son two weeks ago.
"He Skyped us on the 30th of June for his mother's birthday. We were also getting emails with photos from him every couple of days."
It was reported last year that 28 base jumpers had died in the Swiss mountain region. About 15,000 jumps were recorded.
