A 21-year-old woman has died in a nightmare accident, after two rope jump instructors threw her from a bridge in Brazil without harnessing her to security equipment.

Maria Eduarda Rodrigues de Freitas was going rope jumping on Saturday at Ponte do Esqueleto or Skeleton Bridge, an abandoned bridge in the municipality of Limeira where tourists practise extreme sports.

The young woman, who wanted to be a physical education teacher, had asked to be launched from the bridge aeroplane style, with two instructors hoisting her above their shoulders as she spread out her arms.

“Who was the crazy person who let me jump off a bridge?” she allegedly joked on her Instagram Stories before the fatal fall.

Footage shared online shows two men in white helmets launching Rodrigues de Freites into a 40-metre abyss without attaching her to any security equipment as an onlooker screams at the instructors to attach her to a cord.

“Guys, the rope!” the witness can be heard yelling.

The instructors are wearing harnesses that appear to be attached to a security rope.

An emergency helicopter was called but Rodrigues de Freites was declared dead at the scene. Her fiance was among the onlookers and fell ill afterwards.

Rope jumping is an extreme sport that differs from bungee jumping in the type of cord used and the resulting motion of the fall.

Bungee jumping uses elastic rubber cords that create a vertical, bouncing effect, whereas rope jumping uses low-stretch climbing ropes that convert the fall into a horizontal, pendulum swing.

The man credited with inventing it, American Dan Osman, died during one of his jumps in 1998. He was 35.

Brazilian publication G1 said six people had been brought in for questioning after Rodrigues de Freites’ fatal fall. It said three men – aged 27, 32 and 42 – had been arrested at the scene and charged with homicide with implied malice.

“It was a team there that wasn’t regulated; they didn’t even have authorisation to be there,” Delegate Andrea Dantas Levy reportedly told G1.

“They ended up organising this event, and this fatality happened today, in my perception, due to a failure to verify and supervise the placement of the rope on the victim’s jump.”

Lawyers for the three men told the publication that they were experienced and it was their first fatality in years of operation.

The video of Rodrigues de Freitas falling to her death has gone viral on social media platforms. Internet users are describing her death as a surreal case of negligence.

-with AAP