2 Injured as ‘Rocketeer’ Movie Stunt Goes Astray : Film: Actors are accidentally catapulted off the front lawn of the Griffith Observatory and over a cliff.

Two stuntmen pretending to be propelled by an out-of-control rocket backpack for a movie scene were injured early Saturday when they were catapulted off the front lawn of the Griffith Observatory and over a cliff.

Jim Madieras, 50, was critically injured when he was thrown headfirst into a tree about 50 feet down the steep embankment, authorities said. Michael Sarna, 25, suffered less serious cuts to his face when he landed in bushes 25 feet down the slope.

The two men were performing a chase scene in front of the observatory for the Walt Disney Co. movie, “The Rocketeer,” when the accident occurred about 3:20 a.m. They were airlifted to County-USC Medical Center by a Los Angeles Fire Department helicopter.

Madieras, who was unconscious for several hours, was listed in critical but stable condition late Saturday afternoon, said hospital spokeswoman Adelaida De La Cerda. Sarna was treated and released.

Police investigators said the stuntmen, both residents of the Santa Clarita Valley, were being pulled across the observatory lawn by a hidden wire for the scene, which depicted a man holding onto another man who was wearing a jet-powered backpack.

The pair were supposed to skim across the lawn near the famous planetarium sundial before crashing through a special balsa wood “breakaway” fence a few steps west of the observatory building, investigators said.

“The scene was set up where one man was wearing a rocket backpack and the other was holding on, a comedy-type sequence,” said Police Sgt. John Johnston.

“They were being pulled by an invisible cable, like the rocket pack was out of control, sending them into a fence. The cable was hooked to a pulley accelerated by a truck.”

The stuntmen were supposed to land on a mattress beyond the fence, just out of camera range, Johnston said.

“There were people there to grab them, but they went up in the air, over the mattress and over the people.”

In a statement issued late Saturday, Disney production executive Mario Iscovich described what happened as “an extremely unfortunate and unforeseeable accident.” He said it was “a routine stunt that had been rehearsed ahead of time to be performed by professionals and all precautions were taken to safeguard these men.”

The accident came hours after state safety investigators announced they had found no evidence of wrongdoing in the case of a movie stuntman who died Sept. 24 after landing improperly on an air bag. Stuntman Jay Currin, 34, was working on the film “Bikini Island” when he jumped 55 feet off a Malibu cliff and landed on a corner of the bag.

The famed Griffith Observatory, used for years in films such as “Rebel Without a Cause,” was decorated 1930s style for the movie. Camouflage netting and fake trees obscured its snack bar, and half a dozen 50-year-old automobiles were parked in front of the planetarium building.

The film, which is being produced by Disney’s Touchstone Pictures in conjunction with the Gordon Co., is set in 1938 Los Angeles and features a ruggedly handsome racing-plane pilot named Cliff Secord who uses the rocket pack to zoom after criminals.

In the story, the main character, played by Bill Campbell, reportedly comes into possession of the rocket pack from a scientist who is on the run from the Nazis.

Campbell, 31, who said he once considered becoming a comic book artist before turning to acting and roles in television shows such as “Dynasty,” said in September that he would let stuntmen do the flying in the film.

“Since the Rocketeer wears a helmet, I think there’s going to be a stuntman. I have no desire to hang from wires,” Campbell told an interviewer.