The central support structure of the ride gave way and the swings people were sitting in flew off the ride, injuring seven children and five adults, including a 3-year-old and a pregnant woman. Source
Flying Chairs, Mundo Divertido, Tijuana, Mexico
Accidents
Theme parks and roller coasters are statistically very, very, very safe. Out of the millions of people who ride the thousands of rides every year, there are only a small handful of incidents. You are statistically more likely to be involved in an accident driving to an amusement park than having one at a park. The rarity of accidents is one reason why the media report them, similar to plane crashes.
Every important element of a ride is inspected on a regular basis and every ride is tested every day without passengers before it opens. A ride might not open, or a safety system might activate, if there is an imperfection. For theme parks to operate, they must obtain insurance and one stipulation is their rides are frequently inspected and signed off by a strict Health & Safety governing body. Every theme park does what they can to prevent accidents because the negative press would be bad for business.
Having said all that, theme park accidents still happen…
Phantom Manor, Disneyland Paris, France
A 45-year-old technician was found dead in the park’s Haunted House after he was believed to have been electrocuted. Source
Shake & Roll, Easter Fair Kortrijk, Belgium
Two riders were injured when one of the ride’s gondola’s detached while in full motion and landed in the street next to the attraction. A similar incident happened twice with another Mondial Shake called Commander in 2012 and 2010.
Tiviri, Juárez Fair, Mexico
A 14-year old boy died when he stuck out his head and arms and was thrown from the Rok ‘n’ Roll knockoff carnival ride. Source (in Spanish)
Pirate Ship, Baoding City Temple Fair, China
A 19-year-old man died when he lost his grip and fell into the ride machinery after repeatedly standing in his seat as the boat swung back and forth. Source
Montaña Rusa, Mundo Divertido, Tijuana, Mexico
Nine people, six under 16-years-old, were injured when the brakes failed and one train crashed into the back of the other in the loading area. Source (in Spanish)
Raptor, Cedar Point, Sandusky, Ohio, USA
A 45-year-old man jumped over the fence to retrieve a mobile phone, was struck by the coaster and died. Source
Formosa Water Park, Taipei, Taiwan
More than 500 people were injured in front of the stage at the “Colour Play Asia” event when powder sprayed onto the crowd ignited and seriously injured nearly 200 people with burns up to 40% of their bodies. Source
Eclipse, Gröna Lund, Stockholm, Sweden
A man jumped a fence on the star flyer, fell two stories down and hit a woman. The man died from his injuries at the hospital five days later and the woman who was struck only suffered minor injuries. Source (in Swedish)
Revolution, Six Flags Magic Mountain, California, USA
A 10-year-old girl died in hospital two days after collapsing unconscious in the Revolution station. The girl had just ridden the coaster before collapsing and was airlifted to a local hospital. The coroner determined that she had an underlying medical condition and was not injured on the ride. Source