Passengers on a tour bus described a terrifying minute or more as a driver lost control before 11-year-old Hannah Francis died.
Extracts of passenger statements were shown in Auckland on Thursday at the inquest into Hannah's death.
And a technical expert told the Coroner's Court the Ruapehu Alpine Lifts bus should not have been on the road on July 28, 2018, the day of the crash.
The bus crashed near the central North Island's Tūroa skifield. Coroner Brigitte Windley has been examining what might prevent a similar tragedy happening in future.
Hannah's father Matt Francis was one of those on board. He previously said problems with the 1994 Mitsubishi Fuso bus started at a sharp hairpin bend.
One passenger said a man jumped from the bus just 10 seconds before the crash.
"The bus started to pick up speed noticeably, due to the gradient of the hill," another witness said.
A woman on the bus said she braced herself in the seat and observed a mother and two girls crouching down on the floor.
"We had no brakes for probably over a minute," a man on board said. "The driver was just trying to steer that bus the whole time."
"The bus was losing control for about one or two minutes before the crash," yet another passenger said in a statement shown to the inquest.
Mike Brown, Transport Specifications managing director, said the gearbox had a fault in need of repair.
Air pressure in the brakes was also discussed.
Brown, whose expertise includes vehicle compliance, said the tour bus had a very different system to car hydraulic brake systems.
He said the bus's air-based system meant the only resistance when applying the brakes came from a spring in a valve.
"If you apply your brake, all you're doing is opening a port on an air system ... to allow air to flow."
"Once you release, then it blocks that off and it allows time for your air to build up again."
Chris Wilkinson-Smith, counsel for NZ Police, asked Brown about technical details including a switch related to air pressure issues and a chain used to enhance grip.
The system had a warning light but the warning light bulb had been removed.
"Is it your firm view that rather than being at the top of this mountain road on that day, it should really be in the workshop getting these things fixed?" Wilkinson-Smith asked.
"Most definitely," Brown replied.
But Brown said brake fade was also a plausible explanation for the catastrophe.
Brake fade, referring to a reduction in stopping power due to repeated use, was discussed last week as a possible cause of the crash.
Some witnesses were unavailable this week and the inquest was adjourned part-heard on Thursday afternoon. It will resume on December 9.
"I know that this is not what any of us anticipated but there has been a lot of information that has come out in the last two weeks," Coroner Windley said.
She said despite much technical evidence being presented at the inquest, it was important to remember the inquest was about Hannah.
"We are thinking very much of her."